Materiały źródłowe

• #1 Microcephaly Causes, a pediatric clinical case review and discussion 

  https://pediatriceducation.org/2017/09/25/what-causes-microcephaly/

  Microcephaly is usually defined as an occipitofrontal head circumference (OFC) more than 2 standard deviations (SD) below the mean for sex, age and ethnicity. Severe microcephaly is used for OFC 3 standard deviations. Rates of microcephaly range from 0.5-12 patients/10,000 live births. […] While the OFC reflects the skull size and growth over time, the main determinant of normal growth of the skull is the brain and therefore, the OFC is considered a marker of brain growth. However, the extent of the microcephaly does not significantly correlate with the degree of developmental delay. […] In Brazil in March 2015, Zika virus became identified as a likely cause of primary microcephaly and an emerging, urgent public health concern, although the virus was identified in 1947. […] Known cause = 59%

• #2 Microcephaly

  https://www.mdpi.com/2227-9067/4/6/47

  Microcephaly is defined as a head circumference more than two standard deviations below the mean for gender and age. Congenital microcephaly is present at birth, whereas postnatal microcephaly occurs later in life. Genetic abnormalities, syndromes, metabolic disorders, teratogens, infections, prenatal, perinatal, and postnatal injuries can cause both congenital and postnatal microcephaly. […] Microcephaly can also be seen as an isolated finding. Outcomes and prognosis vary based on the type (congenital vs. postnatal) and cause of microcephaly. However, without universally accepted standards in defining and reporting microcephaly, studies vary, and some authors separate etiologies and outcomes while others keep them combined, making predicting prognosis for affected patients difficult. […] Microcephaly has been stratified and studied differently based on the etiology and the timing of onset. For example, microcephaly can be stratified into genetic causes, those associated with syndromes or a known constellation of symptoms, secondary to insults to neuronal development including toxins, metabolites, and infections, and proportional microcephaly.

• #3 Microcephaly – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/microcephaly/symptoms-causes/syc-20375051

  Microcephaly can be caused by a variety of genetic and environmental factors. […] Microcephaly usually is the result of a problem with brain development, which can occur in the womb (congenital) or during infancy. Microcephaly may be genetic. Other causes may include: […] Craniosynostosis (kray-nee-o-sin-os-TOE-sis). Early fusing of the joints (sutures) between the bony plates that form an infant’s skull keeps the brain from growing. […] Genetic changes. Down syndrome and other conditions may result in microcephaly. […] Decreased oxygen to the fetal brain (cerebral anoxia). Certain complications of pregnancy or delivery can impair oxygen delivery to a baby’s brain. […] Infections passed to the fetus during pregnancy. These include toxoplasmosis, cytomegalovirus, German measles (rubella), chickenpox (varicella) and Zika virus.

• #3 Microcephaly – Symptoms & causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/microcephaly/symptoms-causes/syc-20375051

  Exposure to drugs, alcohol or certain toxic chemicals in the womb. Any of these may affect fetal brain development during pregnancy. […] Severe malnutrition. Not getting enough nutrients during pregnancy may hurt fetal brain development. […] Uncontrolled phenylketonuria (fen-ul-kee-toe-NU-ree-uh), also known as PKU, in the mother. phenylketonuria (PKU) hampers the mother’s ability to break down the amino acid phenylalanine and may affect brain development of the fetus during pregnancy.

• #4 Microcephaly | Birth Defects | CDC

  https://www.cdc.gov/birth-defects/about/microcephaly.html

  Microcephaly can occur because a babys brain has not developed properly during pregnancy or stopped growing after birth. […] The causes of microcephaly in most babies are unknown. Some known causes of microcephaly are: Infections during pregnancy, such as Zika, toxoplasmosis, or cytomegalovirus. […] Problems with blood supply to the baby’s brain during development.

• #5 Microcephaly

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5483622/

  Microcephaly is defined as a head circumference more than two standard deviations below the mean for gender and age. […] Genetic abnormalities, syndromes, metabolic disorders, teratogens, infections, prenatal, perinatal, and postnatal injuries can cause both congenital and postnatal microcephaly. […] Microcephaly has been stratified and studied differently based on the etiology and the timing of onset. For example, microcephaly can be stratified into genetic causes, those associated with syndromes or a known constellation of symptoms, secondary to insults to neuronal development including toxins, metabolites, and infections, and proportional microcephaly. […] Studies have shown that abnormal neuronal development and migration involving many genes may lead to microcephaly. […] Congenital microcephaly can also result from insults during pregnancy that stop the brain from growing and developing normally. Environmental insults including hypoxic injury, maternal metabolic abnormalities such as Phenylketonuria (PKU), teratogen exposure, and infections can interfere with brain development and lead to congenital microcephaly.

• #6 Microcephaly – Wikipedia

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

  Microcephaly is a type of cephalic disorder. It has been classified in two types based on the onset: […] The disorder is caused by a disruption to the genetic processes that form the brain early in pregnancy, though the cause is not identified in most cases. […] Many genetic syndromes can result in microcephaly, including chromosomal and single-gene conditions, though almost always in combination with other symptoms. […] External toxins to the embryo, such as alcohol during pregnancy or vertically transmitted infections, can also result in microcephaly. […] Genetic mutations cause most cases of microcephaly. […] The spread of Aedes mosquito-borne Zika virus has been implicated in increasing levels of congenital microcephaly by the International Society for Infectious Diseases and the US Centers for Disease Control and Prevention.

• #7 Microcephaly

  https://www.mdpi.com/2227-9067/4/6/47

  Autosomal recessive primary microcephaly (MCPH) is associated with single gene mutations resulting in isolated microcephaly with often normal magnetic resonance imaging (MRIs) and no other physical examination findings. […] Congenital microcephaly can also result from insults during pregnancy that stop the brain from growing and developing normally. Environmental insults including hypoxic injury, maternal metabolic abnormalities such as Phenylketonuria (PKU), teratogen exposure, and infections can interfere with brain development and lead to congenital microcephaly. […] Recently a rise in the number of prenatal Zika virus infections has been linked with microcephaly and other serious brain abnormalities. […] While the majority of cases of microcephaly are congenital, there are cases where insults occur postnatally that affect brain development.

• #8 Autosomal recessive primary microcephaly: MedlinePlus GeneticsLock

  https://medlineplus.gov/genetics/condition/autosomal-recessive-primary-microcephaly/

  Autosomal recessive primary microcephaly (often shortened to MCPH, which stands for „microcephaly primary hereditary”) is a condition in which infants are born with a very small head and a small brain. […] MCPH can result from mutations in at least seven genes. Mutations in the ASPM gene are the most common cause of the disorder, accounting for about half of all cases. […] The genes associated with MCPH play important roles in early brain development, particularly in determining brain size. […] Mutations in any of the genes associated with MCPH impair early brain development. As a result, affected infants have fewer nerve cells (neurons) than normal and are born with an unusually small brain. The reduced brain size underlies the small head size, intellectual disability, and developmental delays seen in many affected individuals.

• #9 WHAT IS MICROCEPHALY? – CAUSES, IMPACT ON DEVELOPMENT AND THE IMPORTANCE OF EARLY DETECTION | Mya Care

  https://myacare.com/blog/what-is-microcephaly-causes-impact-on-development-and-the-importance-of-early-detection

  Microcephaly is a neurological condition that affects infants and children, characterized by an abnormally small head size for their age and gender that negatively impacts brain development. It is a rare condition and according to research, about 1 in every 1,150 babies is born with microcephaly in the United States. […] Multiple causes can lead to microcephaly, all of which interfere with brain growth. Common mechanisms involve factors that cause brain cells to die off or genetic mutations that disrupt cell division. Understanding the causes is essential for early detection and prevention. Well-known microcephaly causes are described below. […] Microcephaly can be a standalone genetic disorder called autosomal recessive primary microcephaly. At least 7 genes have been implicated in causing this disorder, with one of the main mutations known to occur on the X chromosome from each parent. Other inherited conditions that disrupt normal brain growth can also cause microcephaly.

• #10 Microcephaly: Background, Anatomy, Pathophysiology

  https://emedicine.medscape.com/article/2500048-overview

  Microcephaly has recently gained notoriety in the popular press because of its association with the Zika virus, one of many viruses that may lead to microcephaly by first damaging the brain. However, causality has not definitely been proven. […] The etiology of microcephaly can be broadly divided into two categories: premature fusion of cranial sutures (ie, craniosynostosis) or poor brain growth. […] Genetic conditions that can cause microcephaly include the following: Trisomy 21, 13, 18; Cri du Chat syndrome – 5p deletion; Wolf-Hirschhorn syndrome – 4p deletion; Williams syndrome – 7q11.23 deletion; Cornelia de Lange syndrome; Smith-Lemli-Opitz syndrome; Seckel syndrome; Primary autosomal recessive microcephaly (microcephaly primary hereditary [MCPH]) – mutation in the abnormal spindle microtuble assembly (ASPM) gene, which impacts cell division of neural progenitor cells.

• #11 Microcephaly – UF Health

  https://ufhealth.org/conditions-and-treatments/microcephaly

  Microcephaly most often occurs because the brain does not grow at a normal rate. The growth of the skull is determined by brain growth. Brain growth takes place while a baby is in the womb and during infancy. […] Conditions that affect brain growth can cause smaller than normal head size. These include infections, genetic disorders, and severe malnutrition. […] Genetic conditions that cause microcephaly include: Cornelia de Lange syndrome, Cri du chat syndrome, Down syndrome, Rubinstein-Taybi syndrome, Seckel syndrome, Smith-Lemli-Opitz syndrome, Trisomy 18, Trisomy 21. […] Other problems that may lead to microcephaly include: Uncontrolled phenylketonuria (PKU) in the mother, Methylmercury poisoning, Congenital rubella, Congenital toxoplasmosis, Congenital cytomegalovirus (CMV), Use of certain drugs during pregnancy, especially alcohol and phenytoin. […] Becoming infected with the Zika virus while pregnant can also cause microcephaly.

• #12 Microcephaly in Children | Phoenix Children’s Hospital

  https://phoenixchildrens.org/specialties-conditions/microcephaly-children

  Your healthcare provider may advise genetic counseling. You can learn more about the risk of microcephaly in a future pregnancy. […] Parents who have one child with autosomal recessive microcephaly have a 1 in 4 (25%) chance for another child with microcephaly with each pregnancy. For X-linked microcephaly, mothers who are carriers have a 1 in 2 chance that a son will have the disorder. […] If your provider believes the microcephaly was caused by environmental factors and you are still exposed to the toxic substances, ask for referrals to agencies that can help change the situation.

• #13 Zika crisis: What is microcephaly? And what does this mean for babies? – The Washington Post

  https://www.washingtonpost.com/news/to-your-health/wp/2016/02/01/zika-virus-and-microcephaly-scientists-investigate-mystery-of-whether-mosquito-bite-is-responsible-for-brain-defect/

  What is microcephaly and what causes it? The term refers to a rare neurological condition in which children have unusually small heads. In many cases it also means a baby’s brain is smaller and may not have developed properly. The condition can be caused by hundreds of factors, both genetic and environmental. Genetic disorders associated with microcephaly include Down’s syndrome and other chromosomal disorders. Possible environmental factors include lack of oxygen to a baby’s brain in utero or during birth, drug/alcohol use during pregnancy, malnutrition, injury to the brain, exposure to radiation or toxins. Infections such as chicken pox or rubella have also been documented to lead to the condition. […] Mochida said that the prognosis often depends on the cause of the microcephaly. In the cases of viruses, which may also apply to Zika, he said that babies with more severe effects may have been infected during the first trimester because that is when the brain is forming.

• #14 Microcephaly | Boston Children’s Hospital

  https://www.childrenshospital.org/conditions/microcephaly

  Microcephaly has a variety of causes. Knowing the cause is important in predicting what symptoms a child with microcephaly will have. For example, some forms of microcephaly are linked with severe developmental delay or a high risk for seizures, while others are not. Some forms can impair motor function or affect other organs in the body. Microcephaly linked to prenatal infections such as Zika sometimes causes with vision and hearing problems. […] Causes of congenital microcephaly include: […] Prenatal infections: Exposure to the Zika virus, especially in the first trimester of pregnancy, can damage nerve cells in the brain. Other infectious agents can also cause microcephaly, including rubella (German measles), chickenpox, toxoplasma, and cytomegalovirus. […] Genetic mutations: Several hundred genes have been linked with microcephaly, and more are still being discovered. Defects in these genes can interfere with the brains growth. In some cases, microcephaly may be related to Down syndrome or certain neurometabolic disorders.

• #14 Microcephaly | Boston Children’s Hospital

  https://www.childrenshospital.org/conditions/microcephaly

  Other causes during pregnancy: There is evidence that alcohol and substance abuse, inadequate nutrition, untreated phenylketonuria (PKU) or exposure to toxic chemicals and certain prescription drugs during pregnancy can cause microcephaly in a baby. […] Causes of microcephaly during infancy include: […] Genetic mutations […] Traumatic brain injury […] Lack of oxygen to the brain […] An infection in the brain.

• #15 Zika causes microcephaly and other birth defects, CDC concludes | ScienceDaily

  https://www.sciencedaily.com/releases/2016/04/160413194228.htm

  Scientists at the U.S. Centers for Disease Control and Prevention (CDC) have concluded, after careful review of existing evidence, that Zika virus is a cause of microcephaly and other severe fetal brain defects. […] The finding that Zika virus infection can cause microcephaly and other severe fetal brain defects means that a woman who is infected with Zika during pregnancy has an increased risk of having a baby with these health problems. […] Establishing this causal relationship between Zika and fetal brain defects is an important step in driving additional prevention efforts, focusing research activities, and reinforcing the need for direct communication about the risks of Zika.

• #16 Zika Causes Microcephaly and Birth Defects, CDC Says | TIME

  https://time.com/4292697/zika-birth-defects-microcephaly/

  Theres no longer doubt that Zika causes birth defects like microcephaly and other severe brain abnormalities, United States health officials announced on Wednesday. […] The agency published its review in the New England Journal of Medicine. […] It is now clear, the CDC has concluded, that Zika does cause microcephaly, said CDC director Dr. Tom Frieden during a call with reporters. […] The CDC says theres no single piece of evidence that proves the link, but that by reviewing many studies and implementing criteria used to determine a link between an environmental exposure and birth defect, the agency is now certain. […] The researchers felt that the available evidence lined up with the criteria to prove the causal link. […] Now that weve confirmed the causal relationship between Zika and birth defects, we can use this information to redouble our efforts to prevent Zika, more narrowly focus our research and communicate even more directly about the risks of Zika, says Dr. Sonja Rasmussen, lead author of the study and director of the division of public health information and dissemination at the CDC. […] All the evidence supports a causal link, but many questions remain. […] The CDC says brain defects may be just one disorder in a range of health problems caused by the virus.

• #17 Microcephaly: Causes, Complications, and Diagnosis

  https://www.healthline.com/health/microcephaly

  If you contract the cytomegalovirus while youre pregnant, you can transmit it to your fetus through your placenta. […] If youre pregnant and have phenylketonuria (PKU), its important to follow a low-phenylalanine diet. […] Microcephaly may also be caused by certain complications during delivery.

• #18 Microcephaly: Causes, Complications, and Diagnosis

  https://www.healthline.com/health/microcephaly

  Most of the time, abnormal brain development causes this condition. […] Often, the cause of abnormal brain development is unknown. Some genetic conditions can cause microcephaly. […] Microcephaly can also occur when your child is exposed to certain viruses, drugs, or toxins in the womb. For example, using alcohol or drugs while pregnant can cause microcephaly in children. […] The following are other potential causes of microcephaly: […] Zika virus may cause microcephaly and several other serious birth defects. […] If your baby is exposed to this poison, they may develop brain and spinal cord damage. […] If you contract the virus that causes German measles, or rubella, within the first 3 months of pregnancy, your baby may develop severe problems. […] If youre infected with the parasite Toxoplasma gondii while youre pregnant, it can harm your developing baby.

• #19 Azthena logo with the word Azthena

  https://www.news-medical.net/health/Causes-of-Microcephaly.aspx

  Microcephaly is a congenital condition in which the newborn baby’s head is abnormally small head for his or her age or stage of development. […] Various causes of microcephaly include the following: […] Viruses can cause brain developmental issues as well as cell death which can lead to microcephaly. […] If a pregnant woman has rubella, also known as German measles, it can cause congenital microcephaly in the developing child alongside other symptoms such as eye, hearing, and heart issues. […] If a pregnant woman contracts the congenital cytomegalovirus infection, her child has a high chance of contracting the virus too. This can cause neurological issues in infected fetuses leading to microcephaly. […] Similarly, pregnant women infected with the varicella-zoster virus, which causes chicken pox, can pass the infection on to the developing fetus, which can lead to many neurological problems including microcephaly.

• #20 Proving that the Zika virus causes microcephaly

  https://theconversation.com/proving-that-the-zika-virus-causes-microcephaly-53716

  When the Zika virus was first discovered in Uganda in the 1940s, it was thought to be harmless. […] But in the past few months in Brazil, it has been linked with something far worse: microcephaly (an abnormally small brain and head) in newborn babies. […] There is a strong correlation between the spread of Zika in Brazil and the growing number of babies born with microcephaly. […] While this does not prove that the Zika virus is the direct cause of the microcephaly, genetic material from the virus has been detected in both mothers and in their amniotic fluid (a pregnant womans waters), indicating Zika has the potential to infect an unborn baby while in the womb. […] Given that other members of this virus family cause microcephaly in newborn animals, there is good reason to believe that microcephaly and the Zika virus epidemic are linked.

• #21 Zika virus infection during the period of maximal brain growth causes microcephaly and corticospinal neuron apoptosis in wild type mice | Scientific Reports

  https://www.nature.com/articles/srep34793

  Zika virus (ZIKV) infection in pregnant women has been established as a cause of microcephaly in newborns. […] A prospective study of ZIKV-infected pregnant women has reported abnormalities, including microcephaly and intrauterine growth restriction, in 29% of fetuses. […] Initial reports indicate that all trimesters of pregnancy are vulnerable to the effects of maternal ZIKV infection on fetal development, with the most severe phenotypes associated with infection during the first or second trimester. […] This indicates that a variety of brain regions and cell types are vulnerable to apoptosis induced by ZIKV infection during early postnatal development. […] Given the case report of Wallerian degeneration of the descending corticospinal tract in a ZIKV infected fetus, we performed immunohistochemistry for CC3 and CTIP2, a marker for subcortical-projecting neurons, including corticospinal motor neurons.

• #22 Microcephaly: Symptoms, Causes & Outlook

  https://my.clevelandclinic.org/health/diseases/9843-microcephaly

  Microcephaly causes your babys head to be smaller than expected. […] Microcephaly happens when your babys brain needs more time to grow or doesnt develop completely. […] A lack of brain growth or changes to how your childs brain grows can cause microcephaly. […] Some causes of microcephaly include: Genetic changes (mutations) or an underlying genetic condition (such as Down syndrome). […] A lack of oxygen to their brain (cerebral hypoxia or anoxia). […] Their skull fusing together too soon (craniosynostosis). […] Viral infections such as rubella, toxoplasmosis, cytomegalovirus and Zika virus. […] Brain injury or trauma. […] Your child may be more at risk of developing microcephaly if they had exposure to the following during fetal development: Alcohol use disorder or substance use disorder. […] Mercury or lead poisoning. […] Complications of gestational diabetes. […] Malnutrition. […] Complications of metabolic conditions such as phenylketonuria. […] Infections.

• #23 Microcephaly | Pregnancy Birth and Baby

  https://www.pregnancybirthbaby.org.au/microcephaly

  Microcephaly is linked to: […] If you catch Zika virus while pregnant, this can cause microcephaly for your baby. […] Microcephaly can be a sign of fetal alcohol spectrum disorder (FASD). […] Often, the cause of microcephaly is unknown. […] If you get Zika virus while pregnant, it can cause birth differences for your baby, including microcephaly. […] Some cases of microcephaly may be prevented. You can lower the chance of your baby having microcephaly by:

• #24 Microcephaly: Causes & Symptoms | Live Science

  https://www.livescience.com/53699-microcephaly.html

  Microcephaly is a condition in which a child’s brain doesn’t develop properly. The most obvious symptom is that the child has a smaller head than others of the same age and gender. Because the brain doesn’t grow at a normal rate, the skull doesn’t either. There are a number of possible causes; recently an outbreak of the Zika virus in mothers has been linked with microcephaly in babies in Brazil. […] Slower brain growth can be caused by a number of factors. According to the World Health Organization (WHO), the most common causes include: infections in the womb: toxoplasmosis (caused by a parasite found in undercooked meat), rubella, herpes, syphilis, cytomegalovirus and HIV […] exposure to toxic chemicals: maternal exposure to heavy metals like arsenic and mercury, alcohol, radiation, and smoking

• #24 Microcephaly: Causes & Symptoms | Live Science

  https://www.livescience.com/53699-microcephaly.html

  genetic abnormalities such as Down syndrome […] severe malnutrition during fetal life. […] Although the Zika virus has been linked with microcephaly, a definite cause has not been proven, according to Dr. Robert Amler, vice president for government affairs, dean and professor of public health and professor of pediatrics and environmental health science at the New York Medical College in Valhalla, New York. „A sizeable increase in newborns with microcephaly, a serious birth defect, has occurred in Brazil in babies born to mothers who were infected during their pregnancies with Zika virus.”

• #25 Microcephaly | Causes, Symptoms & Treatment | Britannica

  https://www.britannica.com/science/microcephaly

  microcephaly, congenital condition in which an infants head is smaller than the typical size for its age and sex. A microcephalic individual usually also has a brain of diminished size, though often normal in structure. Microcephaly is rare, generally occurring in anywhere from 1 in 10,000 to 1 in 250,000 births globally. […] Two different types of microcephaly are recognized: primary and secondary. Primary microcephaly occurs when the brain does not grow to the normal size in utero. Irradiation of the abdomen in pregnant women or maternal infection with cytomegalovirus, rubella (German measles), toxoplasmosis, varicella (chickenpox), or Zika virus during the first three months of pregnancy may sometimes result in primary microcephaly in the infant. Evidence suggests that maternal alcohol consumption during pregnancy and poor nutrition may also contribute to primary microcephaly. Genetic factors also play a role. For example, autosomal recessive primary microcephaly is caused by mutations of any of at least seven different genes.

• #26 WHAT IS MICROCEPHALY? – CAUSES, IMPACT ON DEVELOPMENT AND THE IMPORTANCE OF EARLY DETECTION | Mya Care

  https://myacare.com/blog/what-is-microcephaly-causes-impact-on-development-and-the-importance-of-early-detection

  Infections like Zika virus, Chickenpox, Toxoplasmosis, Rubella, and Cytomegalovirus contracted during pregnancy can increase the risk of microcephaly in the unborn child. Zika virus is currently the most common infection known to cause microcephaly. […] Exposure to radiation, harmful substances or toxic chemicals during pregnancy, such as heavy metals, smoking, and alcohol, can also contribute to microcephaly. These exposures are often coupled with fetal malnourishment that increase the risk of birth defects. […] Children who experience traumatic brain injuries or brain oxygen deprivation after birth can develop secondary microcephaly. A stroke during pregnancy can deprive the fetus of sufficient oxygen that contributes to microcephaly.

• #27 Microcephaly: Background, Anatomy, Pathophysiology

  https://emedicine.medscape.com/article/2500048-overview

  Maternal deprivation problems can also lead to microcephaly (eg, folate deficiency, malnutrition, and hypothyroidism). […] Postanatal onset microcephaly can result from inborn errors of metabolism including congenital disorders of glycosylation, mitochondrial disorders, peroxisomal disorders, and Menkes disease. Disruptive injuries such as traumatic brain injury, hemorrhagic and ischemic stroke, and hypoxic-ischemic encephalopathy can also lead to microcephaly.

• #28 Azthena logo with the word Azthena

  https://www.news-medical.net/health/Causes-of-Microcephaly.aspx

  A recent outbreak of Zika virus in Brazil has been linked to a spike in the number of cases of microcephaly in newborns, showing that infected pregnant women can pass the virus onto the baby. […] Scientists have observed that a poor diet in mothers during pregnancy can lead to microcephaly in newborn babies. […] Abuse of drugs and alcohol during pregnancy can stunt the development of a child’s brain in the womb and result in microcephaly. […] A condition called craniosynostosis in which bones in the skull start to fuse together while the infant is still growing can prevent the brain from developing properly. […] Downs Syndrome and other diseases resulting from chromosome abnormalities can trigger microcephaly. […] A pregnant mother with phenylketonuria can have phenylalanine building up to dangerous levels in the blood and brain. This can be passed on to the developing child and stunt the development of his or her brain resulting in microcephaly. […] Reduced oxygen supply to the baby’s brain due to any reason during pregnancy and delivery can also result in microcephaly.

• #29 Can a Child With Microcephaly Be Normal?

  https://www.medicinenet.com/can_a_child_with_microcephaly_be_normal/article.htm

  Chromosomal abnormalities: Chromosomal abnormalities such as Down syndrome (trisomy 21) or Patau syndrome (trisomy 13) and other conditions can present with microcephaly. […] Cerebral anoxia (decreased oxygen to the fetal brain): This can occur during pregnancy or at the time delivery, where there is decreased oxygen supply to the fetal brain. […] Severe malnutrition: Inadequate nutrition during pregnancy can affect the baby’s development. […] Craniosynostosis: This is the premature fusing of the joints between the bony plates of the skull. This prevents the brain from growing and developing normally. […] Uncontrolled phenylketonuria (PKU): PKU in the mother can affect the baby’s development. PKU is a birth defect that affects the body’s ability to break down an amino acid called phenylalanine.

• #30 Secondary Microcephaly and HIE – Hope for HIE – Hypoxic Ischemic Encephalopathy

  https://www.hopeforhie.org/secondary-microcephaly-and-hie/

  Secondary microcephaly is a condition where a child’s head grows more slowly than expected after birth, leading to a smaller head size compared to children of the same age and sex. Translated, microcephaly means small head and secondary refers to it happening from something else (vs. congenital). In this case, secondary because HIE caused it. […] This condition can occur due to a brain injury like HIE, infections, or other factors that affect brain development after birth. Unlike primary microcephaly, where a baby is born with a small head, secondary microcephaly develops over time. […] Hypoxic-ischemic encephalopathy (HIE) is a type of brain injury caused by a lack of oxygen and blood flow to the brain around the time of birth. This injury can affect brain development, potentially leading to secondary microcephaly. Babies with moderate to severe HIE are more likely to develop secondary microcephaly due to the impact the brain injury may have on the brain structure itself and its growth and development.

• #31 Microcephaly Birth Injuries | Gilman & Bedigian

  https://www.gilmanbedigian.com/microcephaly-birth-injuries/

  Microcephaly may also develop after birth. During the early years, a child’s head and brain continue to develop. Genetic conditions, syndromes, or acquired injuries during the early stages of life can also cause microcephaly. Causes of postnatal onset microcephaly include: Metabolic disorders, Chromosomal syndromes, Genetic birth defects, Traumatic brain injury, Hypoxic-ischemic encephalopathy (HIE), Stroke, Infections, Meningitis, Kidney failure, Anemia, Congenital heart disease, Malnutrition. […] Genetic mutations in the genes or chromosomes are the most common cause of microcephaly. Genetic testing during pregnancy may identify a number of chromosomal or genetic mutations that may be associated with an increased risk of microcephaly or other conditions.

• #32 Microcephaly: Causes, symptoms, and treatment

  https://www.medicalnewstoday.com/articles/305880

  Microcephaly is a rare neurological condition. A range of genetic conditions, infections, and diseases can cause it. The cause of microcephaly is not always clear. The condition may develop at birth or in the first few years of life. However, certain conditions might have a relationship with its development. Conditions that increase the risk of developing microcephaly include: genetic or chromosomal abnormalities, such as Down syndrome […] infections during pregnancy, such as rubella, toxoplasmosis, cytomegalovirus, chickenpox, and possibly the Zika virus […] severe malnutrition […] craniosynostosis, or premature fusing of the skull suture line […] cerebral anoxia, a condition involving a decrease in oxygen delivery to the brain of a fetus […] maternal uncontrolled phenylketonuria (PKU), a congenital anomaly that restricts the body’s ability to break down a specific amino acid. Environmental factors can also increase the risk of microcephaly. If, while in the womb, the mother exposes a fetus is exposed to illicit drugs, alcohol, or toxins, the risk of the infant developing a brain abnormality is higher. A condition called craniosynostosis can cause microcephaly. In cases of craniosynostosis, the joints between the bones of an infant skull fuse together prematurely, preventing the brain from growing fully. However, this condition is typically reversible with surgery that helps reshape the skull. The Zika virus has links to microcephaly.

• #33 Microcephaly (Chapter 50) – The Causes of Epilepsy

  https://www.cambridge.org/core/books/causes-of-epilepsy/microcephaly/5E8B9EFBC9CA89BC1DC53147959A367D

  Virtually all forms of microcephaly display some degree of simplification of the cortical gyral pattern, with fewer gyri and shallow sulci. […] Disruption of neural progenitor proliferation is but one path leading to microcephaly. […] The ability to distinguish between congenital microcephaly and postnatal microcephaly will be helpful in prioritizing the possible etiologies.

• #34 Microcephaly | Causes, Symptoms & Treatment | Britannica

  https://www.britannica.com/science/microcephaly

  Secondary microcephaly occurs when the brain, roughly normal in size at birth, does not grow thereafter. Brain infection, traumatic brain injury, and oxygen deprivation in the brain are causes of postnatal onset. Secondary microcephaly also can occur in association with certain metabolic disorders or genetic syndromes, such as Rett syndrome.

• #35 Causes of microcephaly in human—theoretical considerations

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10701273/

  As is evident from the theme of the Research Topic Small Size, Big Problem: Understanding the Molecular Orchestra of Brain Development from Microcephaly, the pathomechanisms leading to mirocephaly in human are at best partially understood. […] Understanding the causes that underlie human microencephaly is a fundamental challenge, as it is key for an early diagnosis of this neurodevelopmental disorder and, potentially, for appropriate therapeutic approaches. Here, we present a number of theoretical considerations dissecting proven, as well as possible, causes of human microencephaly as detected at birth. […] Our treatise focuses on the development of the neocortex and comprises two classes of theoretical considerations, addressing (i) a reduced generation of cortical stem and progenitor cells (CSPCs), neurons, and/or macroglial cells (astrocytes, oligodendrocytes); and (ii) a reduced survival of newly generated CSPCs, neurons, and/or macroglial cells.

• #36 Microcephaly from prenatal infection: Clues from Zika study – Boston Children’s Answers

  https://answers.childrenshospital.org/microcephaly-zika/

  Zika infection lowered the levels of RNA and proteins related to the cell cycle — the process by which cells grow, replicate their DNA, and divide. By disrupting normal cell-cycle progression, Zika infection makes it impossible for the developing brain to grow properly. […] Zika infection disrupted transcription factor signaling, altering the expression of genes involved in brain development. In Zika-infected brains, the team found abnormally low levels of many transcription factors that regulate the differentiation of neurons. […] The team identified 61 potentially targetable genes. Molecules targeting them could be tested in the mouse model at different stages to see if the disturbances the team observed are normalized, and whether any potential therapeutics would be safe for developing embryos.

• #36 Microcephaly from prenatal infection: Clues from Zika study – Boston Children’s Answers

  https://answers.childrenshospital.org/microcephaly-zika/

  Prenatal exposure to viruses capable of infecting the fetal brain, particularly in the first trimester, can cause a range of developmental defects in the baby. The Zika epidemic in Brazil during 2015-2016 posed an extreme case, causing hundreds of babies to be born with microcephaly, or an abnormally small head. […] Multiple viruses, including chickenpox, measles, cytomegalovirus, West Nile, and herpes simplex viruses can cause congenital brain diseases in newborns in the U.S. […] Zika infection significantly up-regulated levels of immune proteins in the developing mouse brains, including MHC-1 proteins. This suggests that the virus triggers a substantial immune response that contributes to microcephaly. […] The immune system attacks cells infected with virus. If you can kill those cells, the outcome is usually good. But, if you start killing brain cells that are actively dividing brain cells, especially early in gestation, that can be devastating to brain development.

• #37 Causes of microcephaly in human—theoretical considerations

  https://pmc.ncbi.nlm.nih.gov/articles/PMC10701273/

  There are two principal causes underlying a reduced generation of CSPCs, both of which result in a decreased abundance of specific types of CSPCs, or even of all CSPCs. […] Both causes underlying reduced CSPC abundance ultimately lead to a reduced generation of neurons and/or macroglial cells. […] A reduction in the pool size of either bRG, bIPs, or both types of BPs can result from alterations in the CSPC lineages due to changes in the modes of CSPC divisions that affect the abundance of either bRG, bIPs, or both types of BPs; or a reduced proliferative capacity of either bRG, bIPs, or both types of BPs. […] Microencephaly in human may, of course, also be associated with impaired survival of neurons and/or macroglial cells. […] These examples illustrate the spectrum of disorders that lead to neuronal apoptosis and thus result in microcephaly in human. […] The theoretical considerations about possible causes of microcephaly that we have presented in this treatise make it evident that there likely exists a plethora of pathomechanisms leading to human microcephaly.

• #38 Zika virus infection during the period of maximal brain growth causes microcephaly and corticospinal neuron apoptosis in wild type mice | Scientific Reports

  https://www.nature.com/articles/srep34793

  This observation has clear relevance to a prior report of corticospinal tract pathology in a fetus with microcephaly associated with ZIKV infection. […] We interpret this as indicating that periods of high growth rate may be particularly vulnerable to neurological effects of ZIKV infection. […] This P7 intracranial infection model recapitulates aspects of human neuropathology associated with ZIKV infection, including degeneration of corticospinal neurons, and provides relatively easy to score phenotypes to study neurodevelopmental mechanisms of ZIKV infection.

• #39 Microcephaly: Understanding the Causes, Symptoms, and Treatment Options

  https://www.doctorshubnepal.com/diseases-conditions/microcephaly

  Microcephaly is a rare neurological condition characterized by an infant’s head being significantly smaller than the heads of other children of the same age and sex. […] The causes of microcephaly can be varied and include: […] Genetic mutations can cause microcephaly. […] Environmental factors such as exposure to toxins or radiation during pregnancy can cause microcephaly. […] Maternal health conditions such as hypertension or diabetes can increase the risk of microcephaly. […] Pregnancy complications such as preeclampsia or placental abruption can increase the risk of microcephaly. […] A family history of microcephaly can increase the risk of developing the condition. […] Maternal age greater than 35 years can increase the risk of microcephaly. […] Exposure to environmental toxins or radiation during pregnancy can increase the risk of microcephaly.

• #40 Microcephaly

  https://www.mdpi.com/2227-9067/4/6/47

  Determining the etiology of microcephaly can help further research into the prevention of this condition. It can also provide means for predicting a prognosis and planning early interventions that can aid patients and their families. […] The rise in Zika infections (transmitted by mosquitos) in Brazil during pregnancy became the leading hypothesis for the dramatic increase in microcephaly cases. In April 2016, the CDC released a statement that, after extensive review of the evidence and literature and using criteria to establish causality when evaluating teratogens, it had concluded that a causal relationship exists between prenatal Zika virus infection and microcephaly and other serious brain defects.

• #41 Microcephaly Differential Diagnoses

  https://emedicine.medscape.com/article/2500048-differential

  The main differential consideration is to first determine if the patient has craniosynostosis, a problem with brain growth, or no issues beyond head size. If the etiology is determined to be a problem of brain growth, the clinician should then differentiate between a progressive or static insult. […] The degree of microcephaly may play a role in the physicians likelihood to pursue further workup. Children with a head circumference more than 3 standard deviations below normal are more likely to have underlying structural abnormalities than children with a head circumference between 2 and 3 standard deviations below normal.

• #42 Microcephaly | March of Dimes

  https://www.marchofdimes.org/find-support/topics/planning-baby/microcephaly

  Cerebral anoxia. This is when a babys brain doesnt get enough oxygen. […] Craniosynostosis. This is a birth defect in which the joints (also called sutures) between the bones in a babys skull fuse together too early, before the brain stops growing. […] Traumatic brain injury. This happens when a head injury causes brain damage. […] Metabolic disorders. These are health conditions that affect a bodys metabolism. […] Severe malnutrition in the womb. […] Some babies with microcephaly may have long-term or lifelong health problems, including: […] Congenital Zika syndrome. This is a group of health conditions present at birth associated with Zika infection during pregnancy. Congenital Zika syndrome includes birth defects (like microcephaly) and other health and development problems.

• #43 Microcephaly | March of Dimes

  https://www.marchofdimes.org/find-support/topics/planning-baby/microcephaly

  Intellectual and developmental disabilities. These are problems with how the brain works that can cause a person to have trouble or delays in physical development, learning, communicating, taking care of himself or getting along with others. […] Babies with severe microcephaly can have more of these problems than babies with mild microcephaly. Severe mirocephaly may be life-threatening. […] Theres no cure for microcephaly. Treatment options depend on how severe your babys condition is. […] Babies with severe microcephaly may need special care and treatment.

• #44 Microcephaly | MedLink Neurology

  https://www.medlink.com/articles/microcephaly

  The outcome for intelligence in microcephalic children is generally guarded, and many will have a significant chance of functioning in the low intelligence range. However, it is important to keep in mind that the prognosis of each individual case should be made not on the basis of the head circumference alone but through careful evaluation of the history, physical examination, brain imaging, and laboratory studies, including genetic testing.

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