Neonatal hyperbilirubinaemia in heterozygous giucose-6-phosphate dehydrogenase deficient females

Abstract

G-6-P dehydrogenase (G-6-PD, D-/G-6-P: NADP oxidoreductase, EC 1.1.1.49) activity and the percentage of G-6-PD deficient erythrocytes was determined in 50 girls heterozygous for G6PD deficiency, 25 of whom had had hyperbilirubinemia at birth and 25 who had normal bilirubin levels. The enzymatic activity was 2.32 .+-. 0.87 IU/g Hb in the 1st group and 3.31 .+-. 0.92 IU/g Hb in the 2nd group. The percentage of G-6-PD deficient erythrocytes was 54.1 .+-. 15.3 and 65.3 .+-. 4.0, respectively. The level of enzymatic activity exceeded 4 IU/g Hb and the percentage of G-6-P deficient cells fell below 40% in only 1 of the subjects who had developed hyperbilirubinemia. Levels of enzymatic activity below 4 IU/g Hb, or percentages of G-6-PD deficient erythrocytes higher than 40% can therefore be considered to be associated with a high risk of developing neonatal hyperbilirubinemia. These babies apparently should receive prophylactic treatment with phenobarbital, as do G-6-PD deficient Mediterranean males.