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We report a new beta-thalassaemia allele detected in a young Italian woman, suffering with mild non-haemolytic anaemia (Hb < 10 g/dL) and not showing Hb variant or Heinz bodies. The allele is characterised by duplication of tetranucleotide 'AG/CT' (+1344/+1347) including the invariant dinucleotide 'AG' of IVS-II acceptor splicing site and the first two nucleotides of codon 105. Beta-Globin complementary DNA (cDNA) sequencing did not reveal any mutation and qualitative analysis of the reverse transcription PCR reaction showed that only the proximal 3' splice site present in the duplicated gene is used giving race to an anomalous messenger RNA (mRNA) present in trace (1.5 %) because, most probably, rapidly degraded. In the anomalous mRNA, the insertion causes a frameshift and synthesis of an abnormal truncated beta-chain (139 residues), unable to form Hb variant because of the severe conformational changes. The duplication might have arisen from secondary structures generated by quasi-palindromic sequence 5'-CCCA(C)AG/CT(CC)TGGG-3'. Restriction fragment length polymorphism analysis for the beta-globin haplotype and familiar segregation analysis indicated that the mutant beta-globin gene was associated with the haplotype V.

Mutations of the GJB2 gene, encoding Connexin 26, are the most common cause of hereditary congenital hearing loss in many countries, and account for up to 50% of cases of autosomal-recessive non-syndromic deafness. By contrast, only a few GJB2 mutations have been reported to cause an autosomal-dominant form of non-syndromic deafness. We report on a family from southern Italy in whom dominant, non-syndromic, post-lingual hearing loss is associated with a novel missense mutation in the GJB2 gene. Direct sequencing of the gene showed a heterozygous G--A transition at nucleotide 535, resulting in an aspartic acid to asparagine amino acid substitution at codon 179 (D179N). This mutation occurred in the second extracellular domain (EC2), which would seem to be very important for connexon-connexon interaction.

Molecular diagnosis of hemoglobin (Hb) Lepore-Boston in the fetus was successfully accomplished using maternal blood as a source for fetal cells in three pregnancies at risk for beta-thalassemia/Hb Lepore disease. Taking advantage of the possibility of amplifying Lepore- specific DNA fragments by polymerase chain reaction and of families in which Hb Lepore was inherited by the paternal side, we demonstrated in two cases and excluded in one case the presence of this hemoglobinopathy in the fetus directly on maternal DNA. The diagnosis was concordant with that obtained by traditional approaches in all three cases. Our results unequivocally show that nucleated fetal cells are present in maternal blood during pregnancy, and demonstrate for the first time that prenatal diagnosis of a genetic disease may be feasible without invasive procedures.