Clinical and hematological features of beta(+)-thalassemia (IVS-1 nt 5, G-C mutation) in Thai patients

Seventy-eight patients with IVS-1 nt 5, G-C, which is the common mutation o f beta (+)-thalassemia found in the southern part of Thailand, were studied to determine whether it is possible to predict phenotypic severity from ge netic factors. The clinical phenotype of homozygotes for IVS-1 nt 5, G-C an d compound heterozygotes for IVS-1 nt 5, G-C and beta degrees - or beta (+) -thalassemia were variable and could not be accurately predicted. The assoc iations between concomittant alpha -thalassemia or Hb CS or the presence of XmnI-(G)gamma polymorphism and a mild clinical phenotype are not apparent, indicating the involvement of other ameliorating determinants or genetic m odifications.