title: 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.
authors.affiliation: a Department of Pediatrics , Hamad Medical Corporation , Doha , Qatar.
authors.forename: Madeeha
authors.initials: M
authors.lastname: Kamal
authors.forename: Shaza
authors.initials: S
authors.lastname: Abu-Sirriya
authors.forename: Aseel
authors.initials: A
authors.lastname: Abu-Dayya
authors.forename: Hebah
authors.initials: H
authors.lastname: Al-Khatib
authors.forename: Hadeel
authors.initials: H
authors.lastname: Abu-Ramadan
authors.forename: Miranda
authors.initials: M
authors.lastname: Petrou
authors.forename: Aliaa
authors.initials: A
authors.lastname: Amer
authors.forename: Ramin
authors.initials: R
authors.lastname: Badii
authors.forename: Marina
authors.initials: M
authors.lastname: Kleanthous
mesh_terms: D004909:Erythrocyte Indices; D005838:Genotype; D006801:Humans; D009154:Mutation; D010641:Phenotype; D011159:Population Surveillance; D011780:Qatar / Q000453:epidemiology; D055542:alpha-Globins / Q000235:genetics*; D017085:alpha-Thalassemia / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*
chemical_list: D055542:alpha-Globins
keywords: Qatar; pediatric population; α-Thalassemia (α-thal)