Cerebellar granular layer aplasia in congenital hydrocephalus.

An unusual case of cerebellar granular layer aplasia is reported. A 5-year-old boy was born with hydrocephalus and a peritoneal drainage shunt was placed after the delivery. Symptoms of cerebral paralysis, impaired mental function and cerebellar ataxia had developed gradually. Patient's karyotype was 46,XY. Laboratory tests for cytomegalovirus, Herpes simplex virus, Toxoplasma gondii, human immunodeficiency virus, rubella and hepatitis B virus were negative. Further laboratory investigation showed no signs of Tay-Sachs disease, Niemann-Pick disease, Gaucher disease, phenylketonuria, galactosemia or glycogen storage disease. No congenital malformations were traced in other family members for three generations. Radiation exposure and infections during the pregnancy were refuted.