Materiały źródłowe

• #1 Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14510623/

  It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. […] Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. […] Twenty percent of patients have no detectable genetic abnormality. […] Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. […] Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. […] Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy.

• #2 Angelman syndrome – wikidoc

  https://www.wikidoc.org/index.php/Angelman_syndrome

  Angelman syndrome was first discovered by Dr. Harry Angelman, a British pediatrician, in 1965 during his seminar, where he described three children with the typical facies of the syndrome. […] In 1987, maternal allele deletion in chromosome 15 was first identified in the pathogenesis of Angelman syndrome. […] In 1994 point mutations in UBE3A gene was known to be the gene responsible for Angelman syndrome. […] In 70% of the cases, Angelman syndrome is caused by a sporadic (de novo) maternal deletion in chromosomal region 15q11-13 causing an absence of UBE3A gene, involving the ubiquitin pathway. […] Other causes include paternal uniparental disomy, impringting error, translocation, or single gene mutation in UBE3A. […] 3-5% of cases of Angelman syndrome can be inherited. […] In approximately 10% of cases, no cause can be identified. […] There are no risk factors for developing Angelman syndrome, since most of the cases occur due to a de novo deletion and there is a very small chance for this condition to be hereditary transmitted.

• #3 Angelman Syndrome | Embryo Project Encyclopedia

  https://embryo.asu.edu/pages/angelman-syndrome

  Angelman syndrome is a disorder in humans that causes neurological symptoms such as lack of speech, jerky movements, and insomnia. But in the case of Angelman syndrome, the maternal chromosome numbered 15 has a mutation or deletion in its DNA and a gene on the paternal chromosome 15 is inactivated in some parts the brain. The result is the paternal gene is silenced during development of the sperm, which is called genetic imprinting. Angelman syndrome was one of the first disorders described as caused by genetic imprinting. […] In 1987, Ellen Magenis, a doctor at the Oregon Health Science Center in Portland, Oregon, identified a genetic cause of Angelman Syndrome. She identified children with deletions of genetic material on their 15th chromosomes. The deletions occurred only on the maternal copy of chromosome 15, and not the paternal copy.

• #4 Angelman Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK560870/

  Angelman syndrome is a rare disorder caused by loss of function of the maternal UBE3A. […] One of the causes of AS was found in 1987 through high-resolution chromosome banding technique, which revealed de novo microdeletions in the long arm of chromosome 15 in the region 11-13 (15q11-13). Later it was shown that there are multiple mechanisms other than deletions that can cause AS involving the region 15q11-13. We know now that the primary cause of Angelman syndrome is a selective loss of function of ubiquitin-ligase E3A(UBE3A) in the brain, which is usually expressed maternally. […] Angelman syndrome (AS) is caused by a pathologic lack of expression of the UBE3A gene on the maternal chromosome in combination with physiologic genomic imprinting or silencing on the paternal chromosome in neurons. UBE3A gene is an example of an imprinted gene because it is expressed in a parent of origin-specific manner. The paternal UBE3A gene is imprinted mainly in the neurons and has some level of expression in the rest of the body.

• #5 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Angelman syndrome is caused by the loss of function of a gene called UBE3A. This gene is located on chromosome 15 (humans have 46 chromosomes in total). It carries instructions for making a protein thought to play an important role in the development and function of the nervous system. When the UBE3A gene does not work correctly or is absent, the nervous system does not develop or function in a normal way, which can cause Angelman syndrome. […] There are four genetic mechanisms that affect the maternal copy of the UBE3A gene or the section of chromosome 15 where the UBE3A gene is located, which can cause Angelman syndrome: […] Deletion of the segment of the maternally inherited chromosome 15, where the maternal copy of UBE3A is located. This accounts for around 70% to 75% of cases of Angelman syndrome.

• #6 Angelman Syndrome: What It Is, Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/17978-angelman-syndrome

  Angelman syndrome causes distinct facial characteristics in addition to other symptoms. […] A genetic variant of the UBE3A gene causes Angelman syndrome. This gene provides instructions to make an enzyme called ubiquitin protein ligase E3A, which regulates how your nervous system works. Any loss or damage to this gene causes symptoms of Angelman syndrome. […] If the maternal copy of the UBE3A gene is lost or damaged for any reason, youll have no active copies of the gene in some parts of your brain. This can affect how your nervous system functions. […] Some cases of Angelman syndrome are the result of a yet-to-be-identified genetic variant that isnt the UBE3A gene. […] Most cases arent inherited and happen randomly, without any history of the condition in your biological family. […] Angelman syndrome cant be prevented because it happens due to random genetic changes during fetal development. In most cases, this happens without a known cause.

• #7 Angelman syndrome | Description, Cause, Symptoms, & Treatment | Britannica

  https://www.britannica.com/science/Angelman-syndrome

  Angelman syndrome is caused by loss-of-function mutations in a gene known as UBE3A. Most often, these mutations occur as sporadic (random) deletions of base pairs within the gene. In rare instances, such mutations are inherited on the maternal allele of UBE3A. […] The mechanism by which mutations in UBE3A result in Angelman syndrome is not fully understood. UBE3A expression, however, is known to be essential for normal brain development. The gene encodes ubiquitin protein ligase E3A, an enzyme that targets other proteins for destruction. This activity serves a critical role in maintaining protein homeostasis and appears to have an especially important function at synapses (junctions of communication between neurons).

• #8 Angelman Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK560870/

  Angelman syndrome is a rare disorder caused by loss of function of the maternal UBE3A. […] One of the causes of AS was found in 1987 through high-resolution chromosome banding technique, which revealed de novo microdeletions in the long arm of chromosome 15 in the region 11-13 (15q11-13). Later it was shown that there are multiple mechanisms other than deletions that can cause AS involving the region 15q11-13. We know now that the primary cause of Angelman syndrome is a selective loss of function of ubiquitin-ligase E3A(UBE3A) in the brain, which is usually expressed maternally. […] Angelman syndrome (AS) is caused by a pathologic lack of expression of the UBE3A gene on the maternal chromosome in combination with physiologic genomic imprinting or silencing on the paternal chromosome in neurons. UBE3A gene is an example of an imprinted gene because it is expressed in a parent of origin-specific manner. The paternal UBE3A gene is imprinted mainly in the neurons and has some level of expression in the rest of the body.

• #9 Angelman syndrome: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/angelman-syndrome/

  Many of the characteristic features of Angelman syndrome result from the loss of function of a gene called UBE3A. People normally inherit one copy of the UBE3A gene from each parent. Both copies of this gene are turned on (active) in most of the body’s tissues. However, in nerve cells (neurons) in the brain and spinal cord (central nervous system), only the copy inherited from a person’s mother (the maternal copy) is active. This parent-specific gene activation is caused by a phenomenon called genomic imprinting. If the maternal copy of the UBE3A gene is lost because of a chromosomal change or a gene variant (also known as a mutation), a person will have no active copies of the gene in most parts of the brain. […] Several different genetic mechanisms can inactivate or delete the maternal copy of the UBE3A gene. Most cases of Angelman syndrome (about 70 percent) occur when a segment of the maternal chromosome 15 containing this gene is deleted. In other cases (about 10 to 20 percent), Angelman syndrome is caused by a variant in the maternal copy of the UBE3A gene.

• #10 Angelman Syndrome – Child Neurology Foundation

  https://www.childneurologyfoundation.org/disorder/angelman-syndrome/

  Angelman syndrome is a genetic disorder. It involves a region of chromosome 15. Although it is genetic, it does not have to be inherited from a parent. Usually, it is caused by random genetic changes. These occur very early in the development of an embryo. […] AS is associated with the UBE3A genes. The UBE3A genes are located on chromosome 15. Humans inherit one UBE3A gene from each parent. In AS, the UBE3A gene that comes from the mother is accidentally deleted. […] UBE3A makes a protein important to brain development. In most humans, the UBE3A gene from the father cannot make this protein. This means the UBE3A gene from the mother is essential for normal development. AS occurs when the mother’s copy is deleted. In these cases, there is no functioning gene copy. […] AS can have other causes, too. For instance, AS can result when: Both copies of chromosome 15 are inherited from the father instead of the mother; A mutated variant of UBE3A appears; The UBE3A gene is turned off through a process known as imprinting; The UBE3A gene is missing for any other reason.

• #11 Angelman syndrome | Beacon Health System

  https://www.beaconhealthsystem.org/library/diseases-and-conditions/angelman-syndrome?content_id=CON-20251923

  Angelman syndrome is a condition caused by a change in a gene, called a genetic change. […] Angelman syndrome is caused by changes in a gene, called a genetic change. It’s most often caused by changes in a gene on chromosome 15 called the ubiquitin protein ligase E3A (UBE3A) gene. […] Most often, the maternal copy of the UBE3A gene helps the brain develop. Angelman syndrome happens when part of the maternal copy is missing or damaged. So the brain can’t get the information it needs to develop and control speech and movement. […] Rarely, Angelman syndrome is caused when two paternal copies of the gene are passed down instead of one from each parent.

• #12 Symptoms and Causes – Angelman Syndrome Foundation

  https://www.angelman.org/what-is-as/symptoms-and-causes/

  Some genes on the chromosome are turned on or expressed and others are turned off or silent. In typical humans, the UBE3A gene from our father is silent and the UBE3A gene from our mother helps our brain develop. However, in individuals with Angelman syndrome, there is a problem with the UBE3A gene from the mother and the brain cannot get the information it needs to develop and control speech, movement and learning. All of this action in the chromosomes takes place during fetal development, and thus is part of a person’s genetic makeup. […] When the UBE3A gene does not function normally, the individual has Angelman syndrome. Scientists around the world, are studying the UBE3A gene and trying to find ways to turn on or unsilence the copy from the father.

• #13 Genetics of AS – Angelman Syndrome Foundation

  https://www.angelman.org/what-is-as/genetics-of-angelman-syndrome/

  Angelman syndrome is caused by a problem with the UBE3A gene located at the 15th chromosome. It’s important to keep in mind that in typical humans, the UBE3A gene from our father is silent and the brain uses the UBE3A gene from our mother during development. […] There are 4 ways that Angelman syndrome can occur. These are called genotypes. Each genotype has a different mechanism that results in AS. […] The most common (70% of cases of AS) and occurs when the mother’s copy of UBE3A has been deleted and is not present. […] (11% of cases of AS) occurs when there is a mutation or alteration in the 15th chromosome inherited from the mother. This mutation or alteration either prevents the expression of UBE3A or alters its function. […] 6% of cases of AS occurs when there is an abnormality in the imprinting center of the 15th chromosome inherited from the mother. The imprinting center is the area of the chromosome that controls whether genes are turned on or off. So, even though UBE3A from the mother may be present, the problem in the imprinting center makes the UBE3A gene unavailable to the brain. […] 3% of cases of AS occurs when there are two, number 15 chromosomes from the father, but not one from the mother. Since the UBE3A from the father is silenced or turned off, and the one from the mother is absent, the brain cannot get the information it needs from UBE3A.

• #14 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Angelman syndrome is caused by the loss of function of a gene called UBE3A. This gene is located on chromosome 15 (humans have 46 chromosomes in total). It carries instructions for making a protein thought to play an important role in the development and function of the nervous system. When the UBE3A gene does not work correctly or is absent, the nervous system does not develop or function in a normal way, which can cause Angelman syndrome. […] There are four genetic mechanisms that affect the maternal copy of the UBE3A gene or the section of chromosome 15 where the UBE3A gene is located, which can cause Angelman syndrome: […] Deletion of the segment of the maternally inherited chromosome 15, where the maternal copy of UBE3A is located. This accounts for around 70% to 75% of cases of Angelman syndrome.

• #15 Orphanet: Angelman syndrome

  https://www.orpha.net/en/disease/detail/72

  Different genetic mechanisms may cause Angelman syndrome, such as deletion of the 15q11.2-q13 critical region (60-75%), paternal uniparental disomy (2-5%), imprinting defect (2-5%) and mutation in the UBE3A gene (10%). In a group representing 5-26% of patients, the genetic defect remains unidentified.

• #16 Angelman Syndrome | Genetic Disorder | ForPatients by Roche

  https://forpatients.roche.com/en/trials/neurodevelopmental-disorder/angelman-syndrome.html

  Angelman syndrome (also called AS) is a rare genetic disorder that affects the normal development of the nervous system of an infant. The main cause is a genetic problem with the UBE3A gene, but some children can have problems with additional genes, too. […] In people without Angelman syndrome, the UBE3A gene, which is located on chromosome 15, is turned on (expressed) on the mothers copy, and is turned off (silenced) on the fathers copy. However, in people with Angelman syndrome, the mothers copy is missing or malfunctioning, and the fathers copy is turned off. This means that neither copy is creating the UBE3A protein, and the material that the developing brain needs is missing. This leads to problems with developing, controlling speech, movement, learning and sleeping. […] There are four different genetic types of Angelman syndrome: Deletion: Part of chromosome 15 is deleted, causing the maternal copy of UBE3A and single copies of a few other neighbouring genes important for development to be physically missing (so-called deletion AS)

• #17 Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14510623/

  It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. […] Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. […] Twenty percent of patients have no detectable genetic abnormality. […] Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. […] Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. […] Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy.

• #18 Medical Definition of Angelman syndrome

  https://www.rxlist.com/angelman_syndrome/definition.htm

  Angelman syndrome is due in most cases to a chromosome deletion involving loss of material from chromosome region 15q11-q13. The loss is consistently of the contribution of chromosome region 15q11-q13 from the mother. This loss is due to a new deletion in most cases. […] Deletion of chromosome region 15q11-q13 causes both Angelman syndrome and a totally different disorder called Prader-Willi syndrome. However, while the deleted chromosome is of maternal origin in Angelman syndrome, it is the paternal chromosome that is partially deleted in the Prader-Willi syndrome. […] There are rare families with more than one child with Angelman syndrome. The mode of inheritance in these families is autosomal dominant modified by imprinting.

• #19 Angelman syndrome – Wikipedia

  https://en.wikipedia.org/wiki/Angelman_syndrome

  In an individual with AS, however, the maternal UBE3A gene is absent or not functioning normally. […] This can be due to genetic errors such as the deletion or mutation of a segment of chromosome 15, uniparental disomy, or translocation. […] While Angelman syndrome can be caused by a single mutation in the UBE3A gene, the most common genetic defect leading to Angelman syndrome is a 5- to 7-Mb (megabase) maternal deletion in chromosomal region 15q11.2-q13. […] Region 15q11-13 is implicated in both Angelman syndrome and Prader-Willi syndrome (PWS). […] While AS results from mutation, loss or abnormal imprinting involving the UBE3A gene within this region on the maternal chromosome, loss of a different cluster of genes within the same region on the paternal chromosome causes PWS.

• #20 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Certain mutations in the maternal copy of the UBE3A gene, which account for about 10% to 20% of cases. […] Paternal uniparental disomy (UPD) of chromosome 15, which accounts for around 3% to 7% of Angelman syndrome cases. […] Imprinting center defects on chromosome 15, which account for 3% to 5% of cases of Angelman syndrome. The symptoms and features of Angelman syndrome may vary based on the genetic mechanism that causes the condition. […] In rare cases, with a partial genetic deficiency of UBE3A due to mosaic mutations of UBE3A or an imprinting mutation, their presentations are significantly milder.

• #21 Angelman syndrome (AS, MIM 105830) | European Journal of Human Genetics

  https://www.nature.com/articles/ejhg200967

  A small percentage of patients (25%) have paternal UPD for chromosome 15. […] Mutations in the imprinting centre (IC) (imprinting centre defect) are present in about 25% of the patients. […] Mutations in the UBE3A gene were first described in 1997 by Kishino et al and Matsuura et al and are present in about 10% of the patients.

• #22 Angelman syndrome genotypes manifest varying degrees of clinical severity and developmental impairment | Molecular Psychiatry

  https://www.nature.com/articles/s41380-020-0858-6

  Angelman Syndrome (AS) is a severe neurodevelopmental disorder due to impaired expression of UBE3A in neurons. There are several genetic mechanisms that impair UBE3A expression, but they differ in how neighboring genes on chromosome 15 at 15q11q13 are affected. AS is due to the lack of expression of the maternal copy of UBE3A in the chromosome 15q11q13 region. In AS, UBE3A expression is impaired either through deletions including the maternal copy of UBE3A or through one of several other mechanisms: pathogenic variants of the maternal copy of UBE3A (Mut), imprinting defects (IPD), and paternal uniparental disomy (UPD) of chromosome 15. Deletions account for ~70% of all AS diagnoses, UBE3A pathogenic variants, IPD, and UPD for ~10% each. Individuals with UPD have two paternal copies of the chromosome 15q11q13 segment and therefore two silenced copies of UBE3A, resulting in a near-complete lack of expression in neurons. Imprinting center defects (IPDs) can result from epigenetic events (~85%) or deletions within the AS imprinting center (~15%) and effectively cause the maternal chromosome 15q11q13 region to behave like the paternal copy. UBE3A pathogenic variants lead to a selective impairment of expression of functional UBE3A protein, leaving expression of other genes presumably intact. Many of these variants occur de novo, but a substantial portion are inherited from a mother who carries the mutation on her paternally inherited gene. UBE3A pathogenic variants can be further grouped into missense mutations (MutM) and truncating mutations (MutT). Our results revealed that individuals with UPD are more severely impaired than other non-deletion types and, in particular, more impaired than MutT, the genetic group that highly likely leads to a specific and complete impairment of UBE3A expression. This raises the question of whether UPD would be phenotypically closer to deletion AS compared with other non-deletion AS genotypes. In summary, the analysis of non-deletion AS revealed a complex picture suggesting different degrees of clinical severity that can be plausibly related to differences in the genetic irregularities.

• #23 Angelman syndrome genotypes manifest varying degrees of clinical severity and developmental impairment | Molecular Psychiatry

  https://www.nature.com/articles/s41380-020-0858-6

  Angelman Syndrome (AS) is a severe neurodevelopmental disorder due to impaired expression of UBE3A in neurons. There are several genetic mechanisms that impair UBE3A expression, but they differ in how neighboring genes on chromosome 15 at 15q11q13 are affected. AS is due to the lack of expression of the maternal copy of UBE3A in the chromosome 15q11q13 region. In AS, UBE3A expression is impaired either through deletions including the maternal copy of UBE3A or through one of several other mechanisms: pathogenic variants of the maternal copy of UBE3A (Mut), imprinting defects (IPD), and paternal uniparental disomy (UPD) of chromosome 15. Deletions account for ~70% of all AS diagnoses, UBE3A pathogenic variants, IPD, and UPD for ~10% each. Individuals with UPD have two paternal copies of the chromosome 15q11q13 segment and therefore two silenced copies of UBE3A, resulting in a near-complete lack of expression in neurons. Imprinting center defects (IPDs) can result from epigenetic events (~85%) or deletions within the AS imprinting center (~15%) and effectively cause the maternal chromosome 15q11q13 region to behave like the paternal copy. UBE3A pathogenic variants lead to a selective impairment of expression of functional UBE3A protein, leaving expression of other genes presumably intact. Many of these variants occur de novo, but a substantial portion are inherited from a mother who carries the mutation on her paternally inherited gene. UBE3A pathogenic variants can be further grouped into missense mutations (MutM) and truncating mutations (MutT). Our results revealed that individuals with UPD are more severely impaired than other non-deletion types and, in particular, more impaired than MutT, the genetic group that highly likely leads to a specific and complete impairment of UBE3A expression. This raises the question of whether UPD would be phenotypically closer to deletion AS compared with other non-deletion AS genotypes. In summary, the analysis of non-deletion AS revealed a complex picture suggesting different degrees of clinical severity that can be plausibly related to differences in the genetic irregularities.

• #24 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Certain mutations in the maternal copy of the UBE3A gene, which account for about 10% to 20% of cases. […] Paternal uniparental disomy (UPD) of chromosome 15, which accounts for around 3% to 7% of Angelman syndrome cases. […] Imprinting center defects on chromosome 15, which account for 3% to 5% of cases of Angelman syndrome. The symptoms and features of Angelman syndrome may vary based on the genetic mechanism that causes the condition. […] In rare cases, with a partial genetic deficiency of UBE3A due to mosaic mutations of UBE3A or an imprinting mutation, their presentations are significantly milder.

• #25 Angelman syndrome (AS, MIM 105830) | European Journal of Human Genetics

  https://www.nature.com/articles/ejhg200967

  A small percentage of patients (25%) have paternal UPD for chromosome 15. […] Mutations in the imprinting centre (IC) (imprinting centre defect) are present in about 25% of the patients. […] Mutations in the UBE3A gene were first described in 1997 by Kishino et al and Matsuura et al and are present in about 10% of the patients.

• #26 Genetics of AS – Angelman Syndrome Foundation

  https://www.angelman.org/what-is-as/genetics-of-angelman-syndrome/

  Angelman syndrome is caused by a problem with the UBE3A gene located at the 15th chromosome. It’s important to keep in mind that in typical humans, the UBE3A gene from our father is silent and the brain uses the UBE3A gene from our mother during development. […] There are 4 ways that Angelman syndrome can occur. These are called genotypes. Each genotype has a different mechanism that results in AS. […] The most common (70% of cases of AS) and occurs when the mother’s copy of UBE3A has been deleted and is not present. […] (11% of cases of AS) occurs when there is a mutation or alteration in the 15th chromosome inherited from the mother. This mutation or alteration either prevents the expression of UBE3A or alters its function. […] 6% of cases of AS occurs when there is an abnormality in the imprinting center of the 15th chromosome inherited from the mother. The imprinting center is the area of the chromosome that controls whether genes are turned on or off. So, even though UBE3A from the mother may be present, the problem in the imprinting center makes the UBE3A gene unavailable to the brain. […] 3% of cases of AS occurs when there are two, number 15 chromosomes from the father, but not one from the mother. Since the UBE3A from the father is silenced or turned off, and the one from the mother is absent, the brain cannot get the information it needs from UBE3A.

• #27 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Certain mutations in the maternal copy of the UBE3A gene, which account for about 10% to 20% of cases. […] Paternal uniparental disomy (UPD) of chromosome 15, which accounts for around 3% to 7% of Angelman syndrome cases. […] Imprinting center defects on chromosome 15, which account for 3% to 5% of cases of Angelman syndrome. The symptoms and features of Angelman syndrome may vary based on the genetic mechanism that causes the condition. […] In rare cases, with a partial genetic deficiency of UBE3A due to mosaic mutations of UBE3A or an imprinting mutation, their presentations are significantly milder.

• #28 Orphanet: Angelman syndrome

  https://www.orpha.net/en/disease/detail/72

  Different genetic mechanisms may cause Angelman syndrome, such as deletion of the 15q11.2-q13 critical region (60-75%), paternal uniparental disomy (2-5%), imprinting defect (2-5%) and mutation in the UBE3A gene (10%). In a group representing 5-26% of patients, the genetic defect remains unidentified.

• #29 Angelman syndrome genotypes manifest varying degrees of clinical severity and developmental impairment | Molecular Psychiatry

  https://www.nature.com/articles/s41380-020-0858-6

  Angelman Syndrome (AS) is a severe neurodevelopmental disorder due to impaired expression of UBE3A in neurons. There are several genetic mechanisms that impair UBE3A expression, but they differ in how neighboring genes on chromosome 15 at 15q11q13 are affected. AS is due to the lack of expression of the maternal copy of UBE3A in the chromosome 15q11q13 region. In AS, UBE3A expression is impaired either through deletions including the maternal copy of UBE3A or through one of several other mechanisms: pathogenic variants of the maternal copy of UBE3A (Mut), imprinting defects (IPD), and paternal uniparental disomy (UPD) of chromosome 15. Deletions account for ~70% of all AS diagnoses, UBE3A pathogenic variants, IPD, and UPD for ~10% each. Individuals with UPD have two paternal copies of the chromosome 15q11q13 segment and therefore two silenced copies of UBE3A, resulting in a near-complete lack of expression in neurons. Imprinting center defects (IPDs) can result from epigenetic events (~85%) or deletions within the AS imprinting center (~15%) and effectively cause the maternal chromosome 15q11q13 region to behave like the paternal copy. UBE3A pathogenic variants lead to a selective impairment of expression of functional UBE3A protein, leaving expression of other genes presumably intact. Many of these variants occur de novo, but a substantial portion are inherited from a mother who carries the mutation on her paternally inherited gene. UBE3A pathogenic variants can be further grouped into missense mutations (MutM) and truncating mutations (MutT). Our results revealed that individuals with UPD are more severely impaired than other non-deletion types and, in particular, more impaired than MutT, the genetic group that highly likely leads to a specific and complete impairment of UBE3A expression. This raises the question of whether UPD would be phenotypically closer to deletion AS compared with other non-deletion AS genotypes. In summary, the analysis of non-deletion AS revealed a complex picture suggesting different degrees of clinical severity that can be plausibly related to differences in the genetic irregularities.

• #30 Angelman Syndrome – Angelman Syndrome Ireland

  https://www.angelman.ie/angelman-syndrome-causes/

  Angelman Syndrome (AS) is a rare neurodevelopmental disorder caused by genetic alterations that primarily affect the nervous system. […] AS results from the loss of function of the maternal UBE3A gene on chromosome 15q11.2-q13, which plays a critical role in brain development and synaptic function. […] There are a few ways that Angelman Syndrome can occur. These are called genotypes. Each genotype has a different mechanism that results in AS. […] Large deletion of maternal UBE3A and other genes. The most common variation and unfortunately, this tends to be the most severe, in terms of symptoms or characteristics. […] Maternal UBE3A gene is silenced due to an imprinting defect. The imprinting center is the area of the chromosome that controls whether genes are turned on or off. […] Mutation in maternal UBE3A gene, preventing function.

• #31 Angelman syndrome: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/angelman-syndrome/

  In a small percentage of cases, Angelman syndrome results when a person inherits two copies of chromosome 15 from his or her father (paternal copies) instead of one copy from each parent. This phenomenon is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a variant or other defect in the region of DNA that controls activation of the UBE3A gene. These genetic changes can abnormally turn off (inactivate) UBE3A or other genes on the maternal copy of chromosome 15. […] The causes of Angelman syndrome are unknown in 10 to 15 percent of affected individuals. Changes involving other genes or chromosomes may be responsible for the disorder in these cases. […] In some people who have Angelman syndrome, the loss of a gene called OCA2 is associated with light-colored hair and fair skin. The OCA2 gene is located on the segment of chromosome 15 that is often deleted in people with this disorder. However, loss of the OCA2 gene does not cause the other signs and symptoms of Angelman syndrome. The protein produced from this gene helps determine the coloring (pigmentation) of the skin, hair, and eyes.

• #32 Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14510623/

  It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. […] Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. […] Twenty percent of patients have no detectable genetic abnormality. […] Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. […] Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. […] Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy.

• #33 Angelman syndrome

  https://www.nhs.uk/conditions/angelman-syndrome/

  Angelman syndrome usually happens when the gene known as UBE3A is either missing or not working properly. […] Most cases of Angelman syndrome are caused by the child not getting a copy of the UBE3A gene from its mother, or the gene not working. This means there’s no active copy of the gene in the child’s brain. […] In a small number of cases, Angelman syndrome happens when a child gets 2 inactive copies of the gene from their father, rather than 1 from each parent. […] Sometimes the cause of Angelman syndrome is unknown. Most children in these unexplained cases have different conditions involving other genes or chromosomes.

• #34 What Causes It? – Foundation For Angelman Syndrome Therapeutics

  https://cureangelman.org.au/what-causes-it/

  The majority of AS cases are caused by deletions on the maternal copy of Chromosome 15. Due to genomic imprinting, only the maternal copy of UBE3A is expressed in the brain. The deletion thus removes the normal expression of this gene in individuals with AS. […] In these individuals, mutations in the UBE3A gene either prevent its expression or function. Thus these individuals do not have the appropriate levels of functional UBE3A in the brain. […] In UPD, the individual has two copies of paternal Chromosome 15. Because UBE3A is not expressed from the paternal copy, these individuals lack normal levels of UBE3A in the brain. […] These individuals may have a deletion of the imprinting centre on Chromosome 15, but cases can also be cause by loss of imprinting information during the mothers oogenesis. Loss of imprinting will prevent expression of the maternal UBE3A gene in the brain. […] In these individuals, all testing for Angelman syndrome is normal, but they still meet the diagnostic criteria for AS. These individuals may have as yet unrecognised mutations that affect UBE3A or genomic imprinting on Chromosome 15.

• #35 Angelman Syndrome: What It Is, Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/17978-angelman-syndrome

  Angelman syndrome causes distinct facial characteristics in addition to other symptoms. […] A genetic variant of the UBE3A gene causes Angelman syndrome. This gene provides instructions to make an enzyme called ubiquitin protein ligase E3A, which regulates how your nervous system works. Any loss or damage to this gene causes symptoms of Angelman syndrome. […] If the maternal copy of the UBE3A gene is lost or damaged for any reason, youll have no active copies of the gene in some parts of your brain. This can affect how your nervous system functions. […] Some cases of Angelman syndrome are the result of a yet-to-be-identified genetic variant that isnt the UBE3A gene. […] Most cases arent inherited and happen randomly, without any history of the condition in your biological family. […] Angelman syndrome cant be prevented because it happens due to random genetic changes during fetal development. In most cases, this happens without a known cause.

• #36 Genetics 101 for Angelman Syndrome

  https://cureangelman.org/genetics-101

  In most cases, Angelman syndrome isn’t inherited. Instead, the genetic differences that cause AS occur as random events during the formation of sperm or egg cells or in early embryonic development. In more rare instances, it is inherited from a parent who carries a UBE3A mutation or a chromosome difference.

• #37 Symptoms, Causes, and Treatments of Angelman Syndrome

  https://www.verywellhealth.com/angelman-syndrome-overview-4171630

  Angelman syndrome is caused by an error in a gene located on chromosome 15 known as the ubiquitin protein ligase E3A (UBE3A) gene. […] With Angelman syndrome, the UBE3A gene is unique in that only the mother’s contribution is active in the brain; the fathers are not. As such, if the maternal gene is missing or damaged, there will be no working copy of the UBE3A gene in the brain. If this happens, Angelman syndrome will invariably occur. […] In around 70 percent of cases, a chromosomal error will cause the complete deletion of chromosome 15, including the UBE3A gene. This error appears random and can affect any pregnancy, whether there is a history of Angelman syndrome or not. […] The remainder of cases would involve either a mutation of the UBE3A gene, the translocation (switching of position) of UBE3A and another gene, or the inheritance of two paternal UBE3A. In cases of UBE3A mutation, mothers with Angelman syndrome have a 50 percent chance of passing the mutation to her baby. […] With that being said, as many as 10 percent of cases have no known cause.

• #38 Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14510623/

  It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. […] Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. […] Twenty percent of patients have no detectable genetic abnormality. […] Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. […] Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. […] Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy.

• #39 Symptoms, Causes, and Treatments of Angelman Syndrome

  https://www.verywellhealth.com/angelman-syndrome-overview-4171630

  Angelman syndrome is caused by an error in a gene located on chromosome 15 known as the ubiquitin protein ligase E3A (UBE3A) gene. […] With Angelman syndrome, the UBE3A gene is unique in that only the mother’s contribution is active in the brain; the fathers are not. As such, if the maternal gene is missing or damaged, there will be no working copy of the UBE3A gene in the brain. If this happens, Angelman syndrome will invariably occur. […] In around 70 percent of cases, a chromosomal error will cause the complete deletion of chromosome 15, including the UBE3A gene. This error appears random and can affect any pregnancy, whether there is a history of Angelman syndrome or not. […] The remainder of cases would involve either a mutation of the UBE3A gene, the translocation (switching of position) of UBE3A and another gene, or the inheritance of two paternal UBE3A. In cases of UBE3A mutation, mothers with Angelman syndrome have a 50 percent chance of passing the mutation to her baby. […] With that being said, as many as 10 percent of cases have no known cause.

• #40 Genetics 101 for Angelman Syndrome

  https://cureangelman.org/genetics-101

  Angelman syndrome is caused by not enough functional UBE3A protein in the brain. […] People living with Angelman syndrome have a genetic difference that affects the maternal UBE3A gene. That difference results in not enough functional UBE3A protein in the brain. […] Most often, this is because the maternal UBE3A gene is missing (Deletion) but it can also happen because of an error inside the gene (Mutation), because a person has two copies of the paternal UBE3A gene (Uniparental disomy (UPD)) or because the maternal UBE3A gene was incorrectly turned off (Imprinting center defect (ICD)). […] The bottom line is that when the maternal UBE3A gene is absent or nonfunctional, there is no UBE3A protein made in the brain. This is what causes Angelman syndrome. […] UBE3A protein helps control how brain cells communicate with each other. It works by marking certain other proteins for removal, which is important for keeping our brain cells healthy and functioning properly. When UBE3A is absent, other proteins can build up, interfering with how brains cells communicate, which then affects learning and muscle control.

• #41 Angelman syndrome | Description, Cause, Symptoms, & Treatment | Britannica

  https://www.britannica.com/science/Angelman-syndrome

  Angelman syndrome is caused by loss-of-function mutations in a gene known as UBE3A. Most often, these mutations occur as sporadic (random) deletions of base pairs within the gene. In rare instances, such mutations are inherited on the maternal allele of UBE3A. […] The mechanism by which mutations in UBE3A result in Angelman syndrome is not fully understood. UBE3A expression, however, is known to be essential for normal brain development. The gene encodes ubiquitin protein ligase E3A, an enzyme that targets other proteins for destruction. This activity serves a critical role in maintaining protein homeostasis and appears to have an especially important function at synapses (junctions of communication between neurons).

• #42 Genetics 101 for Angelman Syndrome

  https://cureangelman.org/genetics-101

  Angelman syndrome is caused by not enough functional UBE3A protein in the brain. […] People living with Angelman syndrome have a genetic difference that affects the maternal UBE3A gene. That difference results in not enough functional UBE3A protein in the brain. […] Most often, this is because the maternal UBE3A gene is missing (Deletion) but it can also happen because of an error inside the gene (Mutation), because a person has two copies of the paternal UBE3A gene (Uniparental disomy (UPD)) or because the maternal UBE3A gene was incorrectly turned off (Imprinting center defect (ICD)). […] The bottom line is that when the maternal UBE3A gene is absent or nonfunctional, there is no UBE3A protein made in the brain. This is what causes Angelman syndrome. […] UBE3A protein helps control how brain cells communicate with each other. It works by marking certain other proteins for removal, which is important for keeping our brain cells healthy and functioning properly. When UBE3A is absent, other proteins can build up, interfering with how brains cells communicate, which then affects learning and muscle control.

• #43 Genetics 101 for Angelman Syndrome

  https://cureangelman.org/genetics-101

  Angelman syndrome is caused by not enough functional UBE3A protein in the brain. […] People living with Angelman syndrome have a genetic difference that affects the maternal UBE3A gene. That difference results in not enough functional UBE3A protein in the brain. […] Most often, this is because the maternal UBE3A gene is missing (Deletion) but it can also happen because of an error inside the gene (Mutation), because a person has two copies of the paternal UBE3A gene (Uniparental disomy (UPD)) or because the maternal UBE3A gene was incorrectly turned off (Imprinting center defect (ICD)). […] The bottom line is that when the maternal UBE3A gene is absent or nonfunctional, there is no UBE3A protein made in the brain. This is what causes Angelman syndrome. […] UBE3A protein helps control how brain cells communicate with each other. It works by marking certain other proteins for removal, which is important for keeping our brain cells healthy and functioning properly. When UBE3A is absent, other proteins can build up, interfering with how brains cells communicate, which then affects learning and muscle control.

• #44 Angelman syndrome | Description, Cause, Symptoms, & Treatment | Britannica

  https://www.britannica.com/science/Angelman-syndrome

  Angelman syndrome is caused by loss-of-function mutations in a gene known as UBE3A. Most often, these mutations occur as sporadic (random) deletions of base pairs within the gene. In rare instances, such mutations are inherited on the maternal allele of UBE3A. […] The mechanism by which mutations in UBE3A result in Angelman syndrome is not fully understood. UBE3A expression, however, is known to be essential for normal brain development. The gene encodes ubiquitin protein ligase E3A, an enzyme that targets other proteins for destruction. This activity serves a critical role in maintaining protein homeostasis and appears to have an especially important function at synapses (junctions of communication between neurons).

• #45 Angelman syndrome – ThinkGenetic Foundation

  https://thinkgenetic.org/diseases/angelman-syndrome/

  Angelman syndrome is caused by the lack of a protein called E6AP, that is made by a gene called ubiquitin-protein ligase E3A (UBE3A). […] A small protein called ubiquitin is known to play a role in neurologic development and neurologic disorders. In Angelman syndrome, a protein that interacts with ubiquitin, called ubiquitin ligase E3A (E6AP) is not produced. […] It is not known exactly how this disruption to the protein breakdown process causes Angelman syndrome, although this is a topic of active research. […] Most of the genetic changes that cause Angelman syndrome happen randomly, during the formation of an egg or sperm, or very early during pregnancy. […] Very rarely, a genetic mutation in the UBE3A gene may be passed on from an unaffected parent to a child. […] Unlike conditions such as autism, which are thought to be the result of a combination of genetic and environmental factors, Angelman syndrome is a genetic disorder that is caused by the loss of function of a gene called UBE3A. […] Although the type of genetic change that causes UBE3A to not work have been correlated with mild differences in severity, there is no indication that environment plays a role in the severity of the major features of Angelman syndrome.

• #46 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Certain mutations in the maternal copy of the UBE3A gene, which account for about 10% to 20% of cases. […] Paternal uniparental disomy (UPD) of chromosome 15, which accounts for around 3% to 7% of Angelman syndrome cases. […] Imprinting center defects on chromosome 15, which account for 3% to 5% of cases of Angelman syndrome. The symptoms and features of Angelman syndrome may vary based on the genetic mechanism that causes the condition. […] In rare cases, with a partial genetic deficiency of UBE3A due to mosaic mutations of UBE3A or an imprinting mutation, their presentations are significantly milder.

• #47 Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14510623/

  It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. […] Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. […] Twenty percent of patients have no detectable genetic abnormality. […] Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. […] Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. […] Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy.

• #48 Angelman syndrome genotypes manifest varying degrees of clinical severity and developmental impairment | Molecular Psychiatry

  https://www.nature.com/articles/s41380-020-0858-6

  Angelman Syndrome (AS) is a severe neurodevelopmental disorder due to impaired expression of UBE3A in neurons. There are several genetic mechanisms that impair UBE3A expression, but they differ in how neighboring genes on chromosome 15 at 15q11q13 are affected. AS is due to the lack of expression of the maternal copy of UBE3A in the chromosome 15q11q13 region. In AS, UBE3A expression is impaired either through deletions including the maternal copy of UBE3A or through one of several other mechanisms: pathogenic variants of the maternal copy of UBE3A (Mut), imprinting defects (IPD), and paternal uniparental disomy (UPD) of chromosome 15. Deletions account for ~70% of all AS diagnoses, UBE3A pathogenic variants, IPD, and UPD for ~10% each. Individuals with UPD have two paternal copies of the chromosome 15q11q13 segment and therefore two silenced copies of UBE3A, resulting in a near-complete lack of expression in neurons. Imprinting center defects (IPDs) can result from epigenetic events (~85%) or deletions within the AS imprinting center (~15%) and effectively cause the maternal chromosome 15q11q13 region to behave like the paternal copy. UBE3A pathogenic variants lead to a selective impairment of expression of functional UBE3A protein, leaving expression of other genes presumably intact. Many of these variants occur de novo, but a substantial portion are inherited from a mother who carries the mutation on her paternally inherited gene. UBE3A pathogenic variants can be further grouped into missense mutations (MutM) and truncating mutations (MutT). Our results revealed that individuals with UPD are more severely impaired than other non-deletion types and, in particular, more impaired than MutT, the genetic group that highly likely leads to a specific and complete impairment of UBE3A expression. This raises the question of whether UPD would be phenotypically closer to deletion AS compared with other non-deletion AS genotypes. In summary, the analysis of non-deletion AS revealed a complex picture suggesting different degrees of clinical severity that can be plausibly related to differences in the genetic irregularities.

• #49 Angelman Syndrome > Fact Sheets > Yale Medicine

  https://www.yalemedicine.org/conditions/angelman-syndrome

  Certain mutations in the maternal copy of the UBE3A gene, which account for about 10% to 20% of cases. […] Paternal uniparental disomy (UPD) of chromosome 15, which accounts for around 3% to 7% of Angelman syndrome cases. […] Imprinting center defects on chromosome 15, which account for 3% to 5% of cases of Angelman syndrome. The symptoms and features of Angelman syndrome may vary based on the genetic mechanism that causes the condition. […] In rare cases, with a partial genetic deficiency of UBE3A due to mosaic mutations of UBE3A or an imprinting mutation, their presentations are significantly milder.

• #50 Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14510623/

  It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. […] Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. […] Twenty percent of patients have no detectable genetic abnormality. […] Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. […] Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. […] Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy.

• #51 Angelman syndrome: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/angelman-syndrome/

  In a small percentage of cases, Angelman syndrome results when a person inherits two copies of chromosome 15 from his or her father (paternal copies) instead of one copy from each parent. This phenomenon is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a variant or other defect in the region of DNA that controls activation of the UBE3A gene. These genetic changes can abnormally turn off (inactivate) UBE3A or other genes on the maternal copy of chromosome 15. […] The causes of Angelman syndrome are unknown in 10 to 15 percent of affected individuals. Changes involving other genes or chromosomes may be responsible for the disorder in these cases. […] In some people who have Angelman syndrome, the loss of a gene called OCA2 is associated with light-colored hair and fair skin. The OCA2 gene is located on the segment of chromosome 15 that is often deleted in people with this disorder. However, loss of the OCA2 gene does not cause the other signs and symptoms of Angelman syndrome. The protein produced from this gene helps determine the coloring (pigmentation) of the skin, hair, and eyes.

• #52 Angelman syndrome: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/angelman-syndrome/

  In a small percentage of cases, Angelman syndrome results when a person inherits two copies of chromosome 15 from his or her father (paternal copies) instead of one copy from each parent. This phenomenon is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a variant or other defect in the region of DNA that controls activation of the UBE3A gene. These genetic changes can abnormally turn off (inactivate) UBE3A or other genes on the maternal copy of chromosome 15. […] The causes of Angelman syndrome are unknown in 10 to 15 percent of affected individuals. Changes involving other genes or chromosomes may be responsible for the disorder in these cases. […] In some people who have Angelman syndrome, the loss of a gene called OCA2 is associated with light-colored hair and fair skin. The OCA2 gene is located on the segment of chromosome 15 that is often deleted in people with this disorder. However, loss of the OCA2 gene does not cause the other signs and symptoms of Angelman syndrome. The protein produced from this gene helps determine the coloring (pigmentation) of the skin, hair, and eyes.

• #53 ANGELMAN SYNDROME: CAUSES, SYMPTOMS, COMPLICATIONS, TREATMENT AND LATEST RESEARCH | Mya Care

  https://myacare.com/blog/angelman-syndrome-causes-symptoms-complications-treatment-and-latest-research

  Research suggests that assisted reproductive technology (ART) may be linked to a slightly increased risk of rare genetic conditions like AS. This condition is related to how genes are „marked” or tagged in the body, a process called methylation. This tagging is especially important in early development. Fertility treatments might interfere with this tagging process. However, the reason why this happens is still under research, including which ART methods might increase the risk.

• #54 ANGELMAN SYNDROME: CAUSES, SYMPTOMS, COMPLICATIONS, TREATMENT AND LATEST RESEARCH | Mya Care

  https://myacare.com/blog/angelman-syndrome-causes-symptoms-complications-treatment-and-latest-research

  Research suggests that assisted reproductive technology (ART) may be linked to a slightly increased risk of rare genetic conditions like AS. This condition is related to how genes are „marked” or tagged in the body, a process called methylation. This tagging is especially important in early development. Fertility treatments might interfere with this tagging process. However, the reason why this happens is still under research, including which ART methods might increase the risk.

• #55 Angelman syndrome – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/angelman-syndrome/diagnosis-treatment/drc-20355627

  A blood test can almost always diagnosis Angelman syndrome. This gene testing can find changes in a child’s chromosomes that indicate Angelman syndrome. […] Rarely, Angelman syndrome happens when a person’s maternal copy of the UBE3A gene is active but changed. […] There’s no cure for Angelman syndrome. Research is looking at targeting certain genes for treatment. Current treatment focuses on managing symptoms and addressing the developmental delays in children with Angelman syndrome.

• #56 Unmet clinical needs and burden in Angelman syndrome: a review of the literature | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/s13023-017-0716-z

  Angelman syndrome (AS) is a rare neurodevelopmental disorder caused by lack of expression of the maternal ubiquitin-protein ligase E3A (UBE3A) gene in the brain. There are 4 known etiologies of AS responsible for the silencing of the UBE3A gene: deletion in chromosome 15q11-q13 (70% of cases), paternal uniparental disomy (UPD; 2% of cases), imprinting defect (3% of cases), and point mutation (10% of cases). […] There are currently no AS-specific systematic treatment approaches; treatment and management is symptomatic with no therapy that addresses the underlying etiology. […] The lack of standardized treatment protocols or approved therapies, combined with the severity of the condition, results in high unmet clinical needs in the areas of motor functioning, communication, behavior, and sleep for individuals with AS and their families.

• #57 What is Angelman Syndrome – Angelman Syndrome Foundation

  https://www.angelman.org/what-is-as/

  Angelman syndrome (AS) is a rare neuro-genetic disorder that occurs in one in 15,000 live births or 500,000 people worldwide. It is caused by a loss of function of the UBE3A gene in the 15th chromosome derived from the mother. […] It is believed that there is a high chance of finding a cure for Angelman syndrome, due to the fact that scientists know what causes AS and have been able to reverse it in mouse models.

• #58 Angelman Syndrome: Symptoms, Causes, Treatment, & More – Care Options for Kids

  https://careoptionsforkids.com/blog/angelman-syndrome

  Angelman syndrome is caused by a mutation in the ubiquitin-protein ligase (UBE3A) gene that causes a loss of function in the 15th chromosome. […] While there currently isnt a cure for AS, there is a high likelihood of finding one due to knowing its root cause. […] In fact, researchers have been able to reverse it in laboratory studies.

• #59 Symptoms and Causes – Angelman Syndrome Foundation

  https://www.angelman.org/what-is-as/symptoms-and-causes/

  Some genes on the chromosome are turned on or expressed and others are turned off or silent. In typical humans, the UBE3A gene from our father is silent and the UBE3A gene from our mother helps our brain develop. However, in individuals with Angelman syndrome, there is a problem with the UBE3A gene from the mother and the brain cannot get the information it needs to develop and control speech, movement and learning. All of this action in the chromosomes takes place during fetal development, and thus is part of a person’s genetic makeup. […] When the UBE3A gene does not function normally, the individual has Angelman syndrome. Scientists around the world, are studying the UBE3A gene and trying to find ways to turn on or unsilence the copy from the father.

• #60 Angelman syndrome Market and Epidemiology forecast

  https://www.delveinsight.com/blog/angelman-syndrome-market

  Angelman syndrome causes are due to genetic abnormalities that involve the chromosome 15q11-13 region, which is subjected to genomic imprinting. These include maternal deletion, paternal uniparental disomy, imprinting defects, point mutations or small deletions within the UBE3A gene, which lies within this region. […] The treatment for the disease include Speech therapy, Behavior modification (to address hyperactivity, aggressive behaviour, sleep disorders, self-injury), Communication therapy (to assess speech development), Occupational therapy (to teach self-care), Physical therapy (to achieve functional mobility), Special education, Social skills training and Anti-epileptic medication- the available treatment targets on managing seizures and the physical and behavioural symptoms of the disease. […] Other than this, the future therapy of Angelman syndrome involves gene therapy candidates like GTX-101 by GeneTx Biotherapeutics; GT-AS/AGIL-AS by PTC Therapeutics. It is expected that it will capture the Angelman syndrome market share.

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