Glucose-6-Phosphate Dehydrogenase Deficiency: Diagnosis, Clinical and Genetic Implications

Abstract

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency exists in varying degrees of severity and may give rise to a correspondingly different clinical syndrome. The milder form of G-6-PD deficiency, found in the American Negro, causes drug-induced and infection-Induced hemolytic anemia. The more severe forms may also give rise to icterus neo-natorum, favism, and even congenital nonspherocytic hemolytic anemia. The gene for G-6-PD is carried on the X chromosome. In females only 1 X chromosome is active in each cell; 2 populations of erythro-cytes, enzyme-deficient and normal, coexist in the blood of female heter-ozygotes for G-6-PD deficiency. This fact has proved to be useful in tracing the origin of tumors. With this technic it has been possible to demonstrate that a carcinoma of the colon in a heterozygous Negro female arose from more than 1 cell. G-6-PD deficiency may be detected by enzymatic assay or by a variety of simple screening procedures. Detection of heterozygotes and diagnosis of enzyme deficiency in individuals who have recently undergone drug-induced hemolytic anemia present special problems.