Molecular Basis of β-Thalassemia in Morocco: Possible Origins of the Molecular Heterogeneity

Abstract

We present the molecular spectrum of β-thalassemia in the Moroccan population obtained by the identification of molecular defects responsible for this disease, and herewith we show that the Moroccan population is genetically heterogeneous; 18 different mutations have been found in the 158 β-globin chromosomes studied. Eight mutations [codon 39 (C → T), FSC-8 (-AA), IVS-II-745 (C → G), −29 (A → G), FSC-6 (-A), IVS-I-110 (G → A), IVS-I-2 (T → C), and IVS-I-1 (G → A)] out of 18 β-thalassemia mutations identified accounted for 76% of the Moroccan β-thalassemia chromosomes. Restriction fragment length polymorphism (RFLP) haplotype analysis showed that the observed genetic diversity originated from both new mutational events and gene flow due to migration.