Beta-thalassemia intermedia and IVS-1 NT6 homozygosis in Brazil.

1. The molecular abnormality of a patient with thalassemia intermedia was identified by DNA amplification (PCR) combined with the use of synthetic oligonucleotide probes. 2. The patient is a homozygote for the T----C substitution at position 6 of the first intervening sequence (IVS1-6) of the beta globin gene. 3. On the basis of this finding, the family, which had been previously reported by us to be a carrier of an unusually mild beta-thalassemia gene, was actually the first example reported of the clinical and biochemical features of beta-thalassemia-Portuguese type.