The frequency of glucose-6-phosphate dehydrogenase phenotypes and sickle cell genes in Al-Qatif oasis

This study was conducted on a selected population of Al-Qatif in Eastern Saudi Arabia to determine the gene frequencies of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and sickle cell (HbS) genes and to study the extent of interaction between the two genes. A total of 960 blood samples collected from Saudi males (515) and females (445) attending the outpatient clinics and hospitals for minor illnesses were subjected to electrophoresis for separation of hemoglobin types and G-6-PD phenotyping and for spectrophotometric determination of G-6-PD activity. The prevalence of HbS heterozygotes was 25.9%, Hb S/b_-thalassemia was 1.563% and HbS homozygotes was 2.917%. The overall gene frequency of HbS was 0.1666. Severe glucose-6-phosphate dehydrogenase deficiency was encountered in a large percentage of the population with a frequency of 0.392 for G-6-PD Mediterranean and 0.0058 for G-6-PD-A- in the male population and 0.2020 and 0.0112 for G-6-PD Mediterranean and G-6-PD-A- in the female population respectively. Partial deficiency was encountered at a frequency of 0.0272 and 0.0697 in the male and female populations respectively. G-6-PD deficiency caused by G-6-PD Mediterranean occurred at a higher frequency in individuals with normal hemoglobin (Hb AA) (0.414 and 0.217 in males and females respectively) compared to the HbS heterozygotes (0.338 and 0.168 in males and females respectively) and HbS homozygotes and HbS bo-thalassemia cases (0.3125 and 0.1852 in males and females respectively). Compared to all areas of Saudi Arabia, Al-Qatif had the highest gene frequencies for HbS and G-6-PD deficiency genes.