The Molecular Basis of α-Thalassemia in the Qatari Pediatric Population

Abstract

α-Thalassemia (α-thal) is widely reported in the Arabian Peninsula as one of the main causes of asymptomatic microcytic hypochromic red blood cells with or without anemia in the pediatric population. This is the first study that provides information about the molecular basis of α-thal in the Qatari population. Qatari school children between the ages of 5 and 15, exhibiting laboratory findings suggestive of microcytic anemia were pooled, and those with a mean corpuscular volume (MCV) of <80.0 fL and a hemoglobin (Hb) electropherogram that ruled out β-thalassemia (β-thal), were narrowed down to a group of 127. This group was screened for the −α^3.7 (rightward) deletion, and the α^−5 nt, α^polyA1 (α^T-Saudi), α^polyA2 mutations. A second group of randomly selected Qatari individuals was also screened in order to determine the population’s allele frequency for the −α^3.7 deletion. Thirty-nine point four percent of the individuals with microcytic hypochromic anemia were positive for the −α^3.7 deletion (heterozygotes 30.0%, homozygotes 9.4%), 2.6% were positive for the α^polyA1 deletion and 0.8% positive for the α^−5 nt mutation. None of the children exhibited changes in α^polyA2. Analysis of the random samples determined that 26.4% were heterozygous and 4.5% homozygous for the −α^3.7 deletion with a 17.7% allele frequency. Our results suggest that a significant number of the Qatari pediatric population with microcytic hypochromic anemia are carriers of α-thal mutations. However, 45.6% of the children failed to exhibit any of the above four mutations tested. This suggests the possibility of other mutations in the Qatari pediatric population that are yet to be elicited.

• α-Thalassemia (α-thal)
• pediatric population
• Qatar

Acknowledgements

The authors would like to thank the Medical Research Centre of Hamad Medical Corporation, Doha, Qatar, for their support and ethical approval.

Declaration of interest

This study was generously funded by the Qatar National Research Fund, Grant No. NPRP 4-053-3-018. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.