In 135 subjects from 54 unrelated families of Czech and Slovak families the authors identified 11 different beta-thalassaemic alleles. In 25 families they proved a IVS I-1 (G-A) mutation. Another 4 "mediterranean" mutations: IVS II-1 (G-A), IVS II-745 (C-G); IVS I-110 (G-A) and mutations in the codon 39 (C-T) were found in 18 families. Mutation IVS I-5 (G-C) found in one family is common in Asia. A frameshift at codons 82/83(-G) found in two families, was described previously only by Schwartz in one families from Azerbaijan. A rare mutation in codon 121 (C-T) is usually characterized as beta-thal. with formation of Heinz bodies. The latter were however found only in one of three families with this allele. Newly detected alleles include: mutation in codon 112 (T-A) found in one family (surprisingly also without formation of Heinz bodies); mutation in CD 115 (GCC-GAC) which results in unstable variant of Hb-Hradec Králové alpha 2 beta 2 115 (G17) Ala-Asp with formation of Heinz bodies and a frame shift in codons 38/39(-C) found in two families. In one of them there was also a new mutation of the promotor area of the G gamma gene (-110 A-C) causing the Swiss type of the disease with hereditary persistence F haemoglobin. The so-called Sicilian type of delta beta thalassaemia caused by deletion of DNA length cca 13 kb starting in IVS-II was found in one patient. alpha-thalassaemic mutations are rare in this population. In addition to common alpha-thalassaemia 2(-3,7 kb) deletion, however, also a new alpha-thalassaemia 2 was found caused by a large (18+kb) deletion involving alpha 1 and theta globin genes. alpha alpha alpha anti 3,7 triplication found in 7 beta-thal. heterozygotes led to deterioration of parameters of the red cell haemogram.

Keywords: Base Sequence; Chromosome Deletion; Codon /genetics/; Czech Republic; Fetal Hemoglobin /genetics/; Hemoglobinopathies /genetics/; Heterozygote; Humans; Molecular Sequence Data; Mutation; Slovakia; alpha-Thalassemia /genetics/; beta-Thalassemia /genetics/