Microcephaly

Microcephaly is a neurological condition in which a person's head circumference is significantly smaller than typical for their age and sex, most often reflecting reduced growth of the brain itself. It may be evident at birth or emerge during the first years of life. The condition arises from many different causes: inherited genetic mutations and chromosomal abnormalities account for a large share of cases, while prenatal exposure to certain viral infections, including Zika virus, cytomegalovirus and rubella, or to toxins such as alcohol and ionizing radiation during pregnancy, can also restrict fetal brain growth. Affected individuals commonly show intellectual disability, delayed motor and speech development, distinctive facial features, seizures and short stature. Severity varies widely, from mild learning differences to profound disability, depending on the underlying cause. Diagnosis rests on measuring head circumference against standardized growth charts and, where an infectious or genetic cause is suspected, targeted testing; no cure exists, so care focuses on developmental support and treating associated complications such as seizures.