Mild clinical expression of S-beta thalassemia in a Brazilian patient withthe beta(+) IVS-I-6 (T -> C) mutation

We report on an eight-year-old Brazilian girl with S-beta(+) thalassemia. T he patient had a steady 10.1 g/dl hemoglobin with 57% HbS. Direct sequence analysis of beta-globin gene showed her to be heterozygous for the IVS-I-6 (T-->C) mutation. This beta(+) thalassemia mutation, sometimes referred to as the Portuguese type, was found to be associated with the C-->T polymorph ism at codon 2. In combination with the beta(S) gene, this mutation results in very mild sickle cell disease symptoms.