We report on an eight-year-old Brazilian girl with S-β+ thalassemia. The patient had a steady 10.1 g/dl hemoglobin with 57% HbS. Direct sequence analysis of β-globin gene showed her to be heterozygous for the IVS-I-6 (T→C) mutation. This β+ thalassemia mutation, sometimes referred to as the Portuguese type, was found to be associated with the C→T polymorphism at codon 2. In combination with the β(s) gene, this mutation results in very mild sickle cell disease symptoms.214431433Antonarakis, S.E., Orkin, S.H., Cheng, T.C., Scott, A.F., Sexton, J.P., Trusko, S., Charache, S., Kazazian Jr., H.H., β Thalassemia in American blacks: Novel mutations in the "TATA" box and an acceptor splice site (1984) Proc. Natl. Acad. Sci. USA, 81, pp. 1154-1158Atweh, G., Forget, B.G., Identification of a β-thalassemia mutation associated with a novel haplotype of RFLPs (1986) Am. J. Hum. Genet., 38, pp. 855-859Baysal, E., Huisman, T.H.J., Detection of common deletional α-thalassemia-2 determinants by PCR (1994) Am. J. Hematol., 46, pp. 208-213Bunn, H.F., Forget, B.G., (1986) Hemoglobin: Molecular, Genetic and Clinical Aspects, , W.B. Saunders Company, PhiladelphiaMartins, C.S.B., Ramalho, A.S., Sonati, M.F., Gonçalves, M.S., Costa, F.F., Molecular characterisation of β thalassaemia heterozygotes in Brazil (1993) J. Med. Genet., 30, pp. 797-798Orkin, S.H., Kazazian Jr., H.H., Antonarakis, S.E., Goff, S.C., Boehm, C.D., Sexton, J.P., Waber, P.G., Giardina, P.J.V., Linkage of β-thalassemia mutations and β-globin gene polymorphisms with DNA polymorphisms in human β-globin gene cluster (1982) Nature, 296, pp. 627-631Treisman, R., Orkin, S.H., Maniatis, T., Specific transcription and RNA splicing defects in five cloned β-thalassaemia genes (1983) Nature, 302, pp. 591-596Weatherall, D.J., Clegg, J.B., (1981) The Thalassaemia Syndromes. 3rd Edn., , Blackwell Scientific Publications, OxfordZago, M.A., Costa, F.F., Freitas, T.C., Bottura, C., Clinical, hematological and genetic features of sickle cell anemia and sickle cell-beta thalassemia in a Brazilian population (1980) Clin. Genet., 18, pp. 58-6
