Glucose-6-phosphate dehydrogenase Beaumont: a new variant with severe enzyme deficiency and chronic nonspherocytic hemolytic anemia

Studies were carried out on erythrocytes and fibroblasts from a 3-year-old white male with severe glucose-6-phosphate dehydrogenase (G6PD) deficiency and chronic nonspherocytic hemolytic anemia. Red blood cell G6PD activity was less than 0.02% of normal values. Since the child's fibroblasts had 2-4% of normal enzymic activity, they were utilized as a source of enzyme for kinetic studies. The G6PD demonstrated marked heat lability, a normal K(m) value for glucose-6-phosphate (56 μmol/l), a nearly normal pH-activity curve, and increased utilization of 2-deoxyglucose-6-phosphate (76% of the rate with glucose-6-phosphate). These studies clearly indicate that this is a new molecular variant (G6PD Beaumont).