sickle cell gene as a multifaceted problem in Saudi Arabia

ABSTRACT

This study was conducted in 34 areas of Saudi Arabia to determine the prevalence of individuals homozygous and heterozygous to sickle cell hemoglobin and to determine the Hb S gene frequency. Over a 10 year period 30,055 samples from Saudi individuals living in 34 different areas of Saudi Arabia were analysed by alkaline and acid electrophoresis using blood samples drawn in EDTA tubes. The overall prevalence of Hb S homozygotes and heterozygotes was 1.058% and 7.356%, respectively and the Hb S gene frequency was 0.0474. When separated on the basis of the province, the highest gene frequency was in the eastern province while the lowest was in the central and northern provinces where in several areas no case of Hb SS or Hb AS were identified. Within each province the different areas showed a remarkable heterogeneity in the prevalence of the Hb S gene. The expected number of Hb S homozygotes were calculated by applying Hardy Weinburg equilibrium and found to be significantly lower than the actual number identified during the study. Sickle cell gene occurs in several areas of Saudi Arabia and the gene frequency correlates with history of malaria endemicity. The Hardy Weinburg equilibrium is limited in providing an estimate of the frequency and this may be due, at least in part, to a high rate of consanguinity, a mild sickle cell disease or a bias due to collection of samples in health centres. However, the frequency of Hb S is sufficient to place it as the most frequent genetic disorder in Saudi Arabia. In addition, the health care requirements, psychosocial burden that Hb S ensue and economical consideration require an effective control program to prevent the birth of Hb S homozygotes