Patterns of sickle cell, thalassaemia and glucose-6-phosphate dehydrogenase deficiency genes in north-western Saudi Arabia.

This study was conducted on 429 blood samples collected from Saudi males and females from Al-Ula in the north-western province of Saudi Arabia in order to determine the frequency of the sickle cell gene, glucose-6-phosphate dehydrogenase (G6PD) deficiency gene, and alpha- and beta-thalassaemia genes, and to investigate the pattern of their interactions. The frequency of the sickle cell gene was 0.0785, while that of the beta-thalassaemia gene was 0.1195. Heterozygous alpha-thalassaemia 2 (- alpha/alpha alpha) was encountered at a frequency of 0.121, while homozygous alpha-thalassaemia 2 (- alpha/- alpha) occurred at a frequency of 0.0046. HbH disease and hydrops fetalis were not encountered. One case with triple alpha-gene arrangement, alpha alpha alpha anti-3.7, was identified. The G6PD deficiency gene frequency was 0.08 and 0.032 in males and females, respectively. Several cases with 2 abnormal genes were encountered. The haematological and biochemical data from the patients with sickle cell disease suggest that the disease in this population is more severe in comparison with cases reported from the eastern population.