['In glucose-6-phosphate dehydrogenase (G6PD) deficiency, the enzyme is deficient in liver cells as well as in erythrocytes. It has been suggested that this may be associated with a more severe clinical presentation of acute viral hepatitis A. The aim of this study is to determine the severity of liver disease in patients with viral hepatitis and G6PD deficiency.', 'Eighteen patients with diagnosed G6PD deficiency and acute hepatitis A were compared with 18 matched control patients with hepatitis A in a university hospital for liver disease severity and clinical outcome.', 'Two of 18 patients with G6PD deficiency had neurological deterioration. Patients with G6PD deficiency had a mean peak prothrombin time (PT) that was significantly prolonged as compared with the control group (15.5 +/- 3.7 vs 12.9 +/- 2.0 s, respectively, P < 0.02), and a significantly higher proportion had an abnormal PT (PT > 13.3 s): 61 versus 11% (P < 0.0001). Hemolysis occurred in 44% of the G6PD deficiency patients. Total and direct bilirubin were significantly higher in all patients with G6PD deficiency, including patients without hemolysis. There was no significant difference in liver enzyme levels between the two groups. Patients with G6PD deficiency had a longer average hospital stay (9.5 +/- 4.8 vs 3.4 +/- 0.8 days, respectively, P < 0.001). There was no difference in the final clinical outcome between the two groups, and recovery of liver function was seen in all patients.'] Is glucose-6-phosphate dehydrogenase deficiency associated with increased initial clinical severity of acute viral hepatitis A?