Clinical and hematological features of codon 17, A-T mutation of beta-thalassemia in Thai patients.

Forty-one patients with codon 17, A-T mutation of beta-thalassemia, which is commonly found in Thailand, were studied to determine whether it is possible to predict phenotypic severity from genetic factors. The clinical phenotype of homozygotes for codon 17, A-T and compound heterozygotes for codon 17, A-T and beta+-thalassemia may be used to predict a severe phenotype with TM. However, the clinical phenotype of compound heterozygotes for codon 17, A-T and beta+-thalassemia or Hb E were variable and could not be accurately predicted. The association of alpha-thalassemia2 and milder disease was and was not evident in patients with codon 17, A-T and Hb E. The association between Hb CS gene or the presence of XmnI-Ggamma polymorphism and a mild clinical phenotype is not apparent, indicating the involvement of other ameliorating determinants or genetic modifications.