Spectrum of beta-globin gene mutations among thalassemia patients in the West Bank region of Palestine.

beta-Thalassemia (thal) is an autosomal recessive disorder that results in hypochromic hemolytic anemia in affected patients. In the West Bank area of Palestine, the prevalence of beta-thal trait is approximately 3.5% among the population, with an estimated 120,000 carriers. Seventeen beta-globin gene mutations could be identified in 148 patients using polymerase chain reaction (PCR), amplification refractory mutation system (ARMS)-PCR and direct sequencing. The predominant mutations included: IVS-I-6 (T --> C) (28.7%), IVS-I-110 (G --> A) (17.6%), codon 37 (G --> A) (10.4%), IVS-I-1 (G --> A) (9%), codons 106/107 (+ G) (6.8%) and codon 39 (C --> T) (4.6%). Other less frequent and rare mutations included: IVS-II-1 (G --> A), codon 5 (-CT), IVS-II-848 (C --> A), -30 (T --> A), codons 8/9 (+ G), IVS-I-5 (G --> C), -28 (A --> C), IVS-II-745 (C --> G), codon 6(-A), codon 27 (G --> T) and codon 30 (AGG --> ACG). Most patients (62.2%) were homozygous for one type of mutation, while the rest (27.3%) were compound heterozygotes. Some patients were heterozygous for beta-thal and sickle cell anemia traits. No mutations could be detected in both alleles of eight patients, while in seven patients only one mutant allele could be detected. Further investigations are needed to resolve the corresponding genotypes of these patients. This study represents a comprehensive investigation of the type, frequency, and distribution of thalassemia mutations among the Palestinian population in the West Bank region of Palestine. A degree of similarity and significant variations was evident in the type and frequency of mutations when the present mutations profile was compared with similar ones among various Arab and non Arab populations. The association between the identified mutations and the corresponding genotypes of our patients with specific polymorphism frameworks in the beta-globin gene was performed and the results revealed linkage disequilibrium.