THE FREQUENCY OF HBS AND GLUCOSE-6-PHOSPHATE-DEHYDROGENASE PHENOTYPESIN RELATION TO MALARIA IN WESTERN SAUDI-ARABIA

This study was conducted on 6265 Saudi males and females living in six different areas i.e. Yanbu, Makkah, Al-Qunfuda, Bisha, Al-Baha and Ja izen, in western Saudi Arabia. It was conceived to determine and relat e the frequency of Hb S and of glucose-6-phosphate dehydrogenase (G-6- PD) deficiency phenotypes in the different areas and to relate them to malaria endemicity. The sickle cell gene was encountered in each of t he areas investigated at frequencies ranging from 0.015 in Yanbu to 0. 115 in Al-Qunfuda. The normal G-6-PD in each region was G-6-PD-B+, and variants identified included G-6-PD-A+, G-6-PD-A-, G-6-PD-Mediterrane an and G-6-PD-Weak. Severe G-6-PD deficiency was encountered in each r egion and was caused mainly by G-6-PD-Mediterranean at frequencies ran ging from 0.0179 to 0.204 in the male population and 0.0064 to 0.1158 in the female population. This paper shows significant differences in the frequencies of G-6-PD phenotypes and Hb S genes within malaria end emic regions.