Pyruvate kinase deficiency as a cause of extreme hyperbilirubinemia in neonates from a polygamist community.

Neonatal hemolytic jaundice is a risk factor for kernicterus. Pyruvate kinase (PK) deficiency is a rare cause of neonatal hemolytic jaundice, with a prevalence estimated at 1 case per 20,000 births in the United States, but with a higher prevalence among the Amish communities in Pennsylvania and Ohio. We discovered four neonates with PK deficiency born in a small community of polygamists. All four had early, severe, hemolytic jaundice. PK deficiency should be considered in neonates with early hemolytic, Coombs-negative, non-spherocytic jaundice, particularly in communities with considerable consanguinity. Such cases should be recognized early and managed aggressively to prevent kernicterus.