Hydrops fetalis associated with red cell pyruvate kinase deficiency.

A hydrops fetalis and multicystic encephalomalacia were diagnosed in a neonate who was one of twins. The co-twin had died 5 weeks prior to delivery. The most likely explantation for both hydrops and multicystic encephalomalacia was fetal anemia caused by a red cell pyruvate kinase deficiency, and aggravated by an intrauterine disseminated intravascular coagulation.