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

ABSTRACT

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/beta-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 beta -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