title: Sickle cell gene in the population of Saudi Arabia.
abstract: A comprehensive screening program was initiated in Saudi Arabia in 1982 to determine the frequency of the sickle cell (Hb S) gene in the different regions of Saudi Arabia. Over a period of 10 years 30,055 samples were collected from 36 areas in the five provinces of Saudi Arabia; these were screened using electrophoretic techniques in alkaline and acid pH for the presence of Hb S in heterozygous and homozygous states. The overall prevalence of Hb AS was 7.36% and Hb SS was 1.06%, giving an Hb S gene frequency of 0.047. The results from the different regions were separated and the prevalence of Hb AS and Hb SS and Hb S gene frequencies were calculated in each province and each region. The prevalence of Hb AS and Hb SS cases ranged from O to 25.88% and O to 5.27%, respectively. No case of Hb AS or Hb SS were identified in certain areas of the central province (Al-Russ, Al-Unaiza, Al-Mesnab and Bkaria) and northern province (Qurayat and Al-Jouf). In the southern province both Hb S homozygotes and heterozygotes were encountered in all regions except Farasan Island. In all other regions the Hb S gene was encountered, but at a variable frequency. Applying Hardy-Weinberg equilibrium it was observed that in the majority of the regions the observed Hb S homozygotes were significantly higher compared to the number expected (p < 0.0001). This was believed to be due to bias as the samples were collected in the hospital. The Hb S gene frequency in the different regions ranged from 0 to 0.17 when the frequency was calculated on the basis of both Hb AS and Hb. SS cases, and 0 to 0.13 if the gene frequency was calculated after eliminating the Hb SS cases. A close correlation was observed between the Hb S gene frequency and malaria endemicity. This study shows that the Hb S gene occurs frequently in several regions of Saudi Arabia and there is an urgent need to implement control and prevention programs to reduce the number of Hb S homozygous cases.
authors.affiliation: Medical Biochemistry Department, College of Medicine King Saud University, Riyadh, Saudi Arabia.
authors.forename: M A
authors.initials: MA
authors.lastname: el-Hazmi
authors.forename: A S
authors.initials: AS
authors.lastname: Warsy
authors.forename: A R
authors.initials: AR
authors.lastname: al-Swailem
authors.forename: A M
authors.initials: AM
authors.lastname: al-Swailem
authors.forename: H M
authors.initials: HM
authors.lastname: Bahakim
mesh_terms: D000755:Anemia, Sickle Cell / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D012529:Saudi Arabia
chemical_list: D006451:Hemoglobin, Sickle