Alpha-thalassemia mutations in adana province, southern Turkey: genotype-phenotype correlation.

Abstract

To look over the distribution of the mutations in a large series from Adana province, Southern Turkey, and determine the genotype-phenotype correlation of the frequent mutations. Among the 2500 individuals with mild or moderate anemia, microcytosis, and normal iron levels that were referred to our Genetic Diagnosis Center, a population consisting of 539 individuals were included in the study and tested for alpha-thalassemia mutations by using reverse dot blot hybridization technique. Twelve different mutations were detected in 539 patients. Among the 12 different mutations found, the most frequent mutations were the -α(3.7) (63.3%), --(MED) (11.7%), --(20.5) (10.7%), α2(IVS1(-5nt)) (3.9%), and α2(polyA-2) (3.5%). The most frequent genotypes were -α(3.7)/αα (35.8%), -α(3.7)/-α(3.7)(18.9%), -(20.5)/αα (11.5%), and --(MED)/αα (10.4%), respectively. There were statistically significant differences in hematological findings between -α(3.7)/-α(3.7) and --(MED)/αα, even though both have two mutated genes in the genotype. Our results show that alpha-thalassemia mutations are highly heterogeneous as well as deletional and -α(3.7) single gene deletion is particularly prevalent at Adana province in agreement to other studies from Turkey.