Glucose-6-phosphate dehydrogenase deficiency: a preventable cause of mental retardation.

Over two years cord blood from 27 879 babies was screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency. The overall incidence was 3.1% in boys and 1.6% in girls. Sixty nine babies had severe jaundice (bilirubin concentration greater than 380 mmol/l (20 mg/100 ml], and exchange transfusion was performed. Parents were given written and verbal instructions to avoid herbs and drugs that trigger kernicterus, which reduced the incidence of kernicterus and thereby prevented mental retardation. G6PD deficiency is common in all three ethnic groups (Malays, Chinese, and Indians) in Malaysia and screening is recommended.