Sickle cell and G-6-PD deficiency gene in cord blood samples: experience at King Khalid University Hospital, Riyadh

Cord blood samples (1039) collected at King Khalid University Hospital were analysed for abnormal haemoglobins using electrophoresis at alkaline and acid pH, for glucose-6-phosphate dehydrogenase (G-6-PD) deficiency using spectrophotometric method and for G-6-PD phenotypes using electrophoresis and specific staining. Only two samples showed the presence of Hb AS and no case of sickle cell anaemia was identified. The Hb S gene frequency was 0.00096. This was the lowest frequency identified so far in different regions of Saudi Arabia. The frequency of G-6-PD deficiency was calculated separately in the males and females, and was found to be 3.605 per cent in the males and 0.195 per cent in the females. Phenotyping showed the presence of G-6-PD-B+ as the normal enzyme at a frequency of 0.943 in both males and females and G-6-PD-A+ at a frequency of 0.0208 in males and 0.0059 in females. The deficient variant was mainly G-6-PD Mediterranean which occurred at a frequency of 0.0341 and 0.0019 in males and females, respectively. Only one case of G-6-PD-A- was identified in the males giving a frequency of 0.0019. This is the first report of Hb S and G-6-PD deficiency genes in cord blood samples in Riyadh. Comparison of the results in Riyadh with values reported elsewhere showed that Riyadh had the lowest frequency of both Hb S and G-6-PD deficiency gene.