effect of-3.7 a-globin gene deletion and gamma-globin gene polymorphism on clinical variability of B-thalassemia in Egyptian patients

Beta-Thalassemias pose by far be most important global public health problem, hence a good undertaning of their natural history and the factors that can modifytheir clinical phenotype is a must to understand the heterogeneity in both phenotype and genotype. Sixty-two beta-thalassima patients classified clinically into severe, late onset and intermedia phenotyps were studied for beta-globin gene mutations, alpha-globin gene [-3.7] deletion and-185 G-T gamma-gobin gene Xmnl polymorphism. Twenty one different beta-thalassemia genotypes were found, alpha globin gene deletions were dtcte in 3.2% of patients and gamma-globin gene XmnI polymorphsm in 4.8% of the studied. Cases cointheritance of alpha delectation and gamma-globin gene polymorphism were associated with intermedia phenotype [in 5.7% of intermedia cases]. Disease severity could not be explained by the beta-globin gene mutation in 20.9% of patients, further genetic studies are needed

Phenotypic scoring in thalassemia intermedia and the impact of underlying molecular defects

Thalassemia intermedia encompasses clinical conditions ranging in severity from, thalassemia carrier sate to transfusion dependent major like. Therefore, classification of patients in useful for proper counseling, management and prenatal diagnosis. We followed a special scoring system for classification of 155 beta-thalassemia intermedia patients. According to this system the patients were classified into mild [23.2%], moderate [27.7%] and severe [49.1%]. Molecular studies for detection of mutations were done for 66 of the cases using Reverse Dot Blot [RDB] and Amplification Refractory Mutation System [ARMS] techniques. Genotypes were compared with the clinical classifications. The mild beta[++]/beta[++] genotype was detected in 38.8% of the mild, 45% of the moderate and 21% of the severe group. We concluded that, the clinical scoring of severity of thalassemia intermedia is useful to develop management guidelines for the subgroups and that severity could not be always explained by the underlying genotype. Search for other mechanisms or modifying factors is needed for proper prognosis, genetic counseling and future