Triose phosphate isomerase deficiency: prenatal diagnosis.

A child with triose phosphate isomerase deficiency has congenital nonspherocytic hemolytic anemia, mental subnormality, motor impairment, growth failure, and cardiac failure. The deficiency state is characterized by moderately reduced red cell triose phosphate isomerase activity and marked instability of the abnormal enzyme to heat. The stability characteristics of triose phosphate isomerase in cultured fibroblasts define the homozygous and heterozygous states with sufficient precision to allow prenatal diagnosis of the disorder. Successful prenatal identification of a heterozygote and an unaffected fetus in utero is described.