Microcephaly
A neurological condition marked by a smaller-than-normal head.
Microcephaly is a medical condition involving a smaller-than-normal head. It may be present at birth or develop in the first few years of life, and brain development is often affected, leading to intellectual disability, poor motor function, poor speech, abnormal facial features, seizures, and dwarfism. The disorder serves as an important neurological warning sign, though no uniformity exists in its definition.
Quick Facts
- Pronounce
- m · ai · k · r · ou · ' · s · E · f · @ · l · i
- Field
- Medical genetics, psychiatry, neurology
- Symptoms
- Abnormally small head and brain, neurological impairments
- Complications
- Neurological impairments
- Onset
- Congenital
- Duration
- Lifelong
- Causes
- Usually genetic or toxin exposure during pregnancy
- Prevention
- Avoiding alcohol consumption while pregnant
- Frequency
- 2–12 per 10,000 births
Facts from the source article.
Lore & Background
Microcephaly 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, 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. There is no specific treatment that returns the head size to normal, and life expectancy is generally reduced, with poor prognosis for normal brain function, though occasional cases develop normal intelligence.
Reader's Guide
Microcephaly is a significant indicator of underlying neurological or developmental issues, often linked to genetic mutations, infections, or environmental exposures during pregnancy. Its definition remains debated, with some advocating a stricter threshold of three standard deviations below the mean. The condition highlights the vulnerability of the developing brain to genetic and environmental insults, as seen in historical cases such as those following the atomic bombings in Hiroshima and Nagasaki, where in utero radiation exposure led to microcephaly. Research into genes like microcephalin (MCPH1) and others has advanced understanding of brain size regulation, while viral infections like Zika have been implicated in recent outbreaks of congenital microcephaly. Despite no cure, microcephaly serves as a critical warning sign for clinicians and researchers.
Did You Know?
- Microcephaly is usually defined as a head circumference more than two standard deviations below the mean for age and sex.
- The disorder can be caused by genetic mutations, vertically transmitted infections, or toxins such as alcohol during pregnancy.
- After the atomic bombings of Hiroshima and Nagasaki, several pregnant women close to ground zero gave birth to children with microcephaly.
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