Gd(-) Carapicuiba, a rare glucose-6-phosphate dehydrogenase variant associated with moderate enzyme deficiency and chronic hemolysis.

1. A 27 year old Brazilian male of both Portuguese and Spanish origin presenting nonspherocytic chronic hemolytic anemia was found to have a rare glucose-6-phosphate dehydrogenase variant herein named Gd(-) Carapicuiba. 2. The red blood cell enzyme variant is characterized by a moderate enzyme deficiency (47%), high Km for its substrates G6P and NADP, decreased activity against deamino-NADP, increased Ki for NADPH and decreased heat stability. 3. The clinical signs of the patient are probably related to these properties of the enzyme variant.