Genotype and phenotype correlation in glucose-6-phosphate dehydrogenase deficiency

Background and Objectives. Glucose-6-phosphate dehydrogenase (G6PD) deficie ncy is the most common erythrocytic enzymatic disorder in Italy and is char acterized by wide clinical, biochemical and molecular variability. We studi ed the clinical and hematologic data from 54 G6PD-deficient, unrelated male s from the Apulia region. Design and Methods. Analyses for enzymatic activity, G6PD electrophoresis a nd molecular typing were performed on all subjects. Thirty-nine subjects (7 2.2%) showed a severe G6PD deficiency (<10% residual enzymatic activity) an d 15 subjects (27.8%) a moderate deficiency (10-60% residual activity). Results. The Mediterranean variant was found in 48.2% of cases, the Seattle variant in 33.3%, the A- variant in 7.45% and the Montalbano variant in 3. 7%; the variant was not identified in four subjects. Thirty-two patients (5 9.2%) were asymptomatic; of these, 37.04% demonstrated acute hemolytic cris es induced mainly by ingestion of fava beans and 3.7% had had neonatal jaun dice. Acute hemolytic anemia was found in 53.8% of subjects with the Medite rranean variant, in 5.5% with the Seattle variant, in 100% with the A-varia nt and 0% with the Montalbano variant. Interpretation and Conclusions. Enzymatic activity was shown to be a poor p redictive parameter of acute hemolytic crises and was not correlated with c linical features. Subjects with Mediterranean or A- variants had a more sev ere clinical phenotype which was not related to enzymatic activity. The Sea ttle, and probably the Montalbano, variant appears to have a milder clinica l expression. (C) 2001, Ferrata Storti Foundation.