1. Two cases of naphthalene hemolytic anemia in the newborn period are reported.
2. Both exhibited glutathione instability upon incubation with acetyl phenylhydrazine and naphthol months to years later. Several members of their families exhibited a similar defect with evidence that it is inherited as a simple dominant.
3. In those individuals with glutathione instability there was deficient TPNH2 generation by their hemolysates in the presence of glucose-6-phosphate and TPN, indicating a deficiency in glucose-6-phosphate dehydrogenase activity. Glutathione reductase activity was normal or decreased.
4. TPNH2-linked reduction of methemoglobin by erythrocyte suspensions in the presence of glucose and methylene blue was also decreased in those subjects tested, a finding consistent with the deficiency in glucose-6-phosphate dehydrogenase.