EFFECT ALPHA GLOBLIN GENE DELETION an‎d GAMMA GLOBIN GENE -158 (C/T) POLYMORPHISM IN BETA-THALASSEMIC PATIENTS

The beta-thalassemias (Beta- thalassemias) are among the most common autosomal recessive disorders. They have a remarkably high frequency in the Mediterranean region and represent one of the most common genetic diseases in Egypt. In this study, the spectrum of Beta-thalassemia mutations and genotype-to-phenotype correlations were defined in 32 Beta- thalassemic patients (Beta- thlassemias major and intermedia) with varying disease severity in two cities of the Suez Canal region. Ten different mutations were identified and the most frequent ones were: IVSI-6 (T-C) (37.5%), IVSI-110 (G-A) (34.4%) and both IVSI-1 (G-A), IVSII-745 (C-G) and -102 (C-G) (12.5% each). There was a wide spectrum of phenotypic severity in all patients. We studied the Xmnl polymorphism (C/T) in y- globin gene position -158 of Beta- thalassemia as a modulating factor of the disease severity. Presence of the polymorphism was found in two patients and this was not sufficient to explain the diversity of the phenotype encountered. Co-inheritance of alpha thalassaemia as a modulating factor was not evident in our patients. In conclusion, we have been unable to find a molecular basis for the benign clinical course in all our patients. Other genetic or acquired factors must be hypothesized which ameliorate the clinical condition.