Alpha thalassaemia in Yemeni children with sickle cell disease.

Abstract

Alpha thalassaemia frequently occurs in several of the Middle Eastern populations. This study was conducted on 26 sickle cell disease (SCD) patients from Yemen and 19 normal children (Hb AA) living in Riyadh, Saudi Arabia. Blood samples were extracted by venepuncture, and haematological and biochemical parameters were estimated. DNA was extracted from the buffy coat and analysed for alpha-gene arrangement using Bam HI and Bgl II. The frequency of alpha-gene deletion in the total Yemeni group (26 SCD + 19 Hb AA) was 0.311 for one alpha-gene deletion (-alpha/alpha alpha) and 0.13 for two alpha-gene deletions (-alpha/-alpha). When separated on the basis of the Hb phenotype the alpha-gene deletion frequency was significantly higher (-alpha/alpha alpha = 0.346 and -alpha/-alpha = 0.231) in the SCD patients compared to the normal Hb AA group (-alpha/alpha alpha = 0.263 and -alpha/-alpha = 0). In the Hb AA group one child had triple alpha-gene arrangement (alpha alpha alpha/alpha alpha) giving an overall frequency of triple alpha-gene as 0.022. Haematological parameters showed variations in the SCD patients with and without alpha-gene deletion. This paper shows for the first time that alpha-gene deletion occurs in the Yemenis and the frequency is higher in patients with SCD. Further population-based studies are required to determine the exact frequency of the different types of alpha-thalassaemias in the overall Yemeni population.