Microcephaly is a characteristic in which the circumference of the head is smaller than normal due to improper development of the brain. It is caused by genetic disorders, infections, radiation, medications or alcohol use during pregnancy. Defects in the growth of the cerebral cortex lead to many of the features associated with microcephaly. Microcephaly has a vast range of prognoses: some patients experience little to very mental retardation and can reach regular age-appropriate milestones. Others may experience severe mental retardation and neuromuscular side effects.
Dubowitz syndrome
Keppen–Lubinsky syndrome
XXYY syndrome
Foster Kennedy syndrome
Ring chromosome 20 syndrome
XYYYY syndrome
Goldberg–Shprintzen syndrome
XYYY syndrome