Quantitative expression of G6PD activity of different phenotypes of G6PD and haemoglobin in a Sudanese population.

597 unrelated persons, comprising of 401 males and 196 females, were investigated for glucose-6-phosphate dehydrogenase (G6PD) and haemoglobin phenotypes by starch gel electrophoresis. The levels of G6PD activity were assayed in order to study the quantitative expression of G6PD phenotypes and the influence of haemoglobin phenotypes on such expression. There was no significant different in the levels of G6PD activity in subjects with GdA or GdB. The mean levels of the enzyme activity were 165.5 +/- 33.7 and 164.8 +/- 33.8 IU/10(12) red cells in males and 159.3 +/- 27.8 and 163.4 +/- 33.5 IU/10(12) red cells in females, respectively. 14 subjects with Gd(+) "Khartoum" had significantly (p less than 0.001) higher level of enzyme activity with a mean above 200 IU/10(12) red cells. On the other hand, 20 subjects with GdB(int) (demonstrated by visual comparison of starch gel) showed significantly (p less than 0.001) lower levels of enzyme activity (107.6 +/- 23.5 IU/10(12) red cells). The heterozygotes GdAB also had slightly, but not significantly lower levels of enzyme activity than either GdA or GdB. The mean level of activity for GdAB was 140.1 +/- 29.4 IU/10(12) red cells.