[New single point mutation at the initiation codon (ATG-AGG) identified in amplified genomic DNA of a Chinese with beta-thalassaemia].

A new single nucleotide change at nt 2 of exon 1 of the beta-globin gene was identified in a Chinese female patient with beta-thalassaemia. Dot blot hybridization of the amplified genomic DNA with oligonucleotide probes showed that she carried the four base deletions at the codons 41/42. Direct DNA sequencing on the amplified DNA revealed that she also carried a new mutation (ATG-AGG) at the initiation codon on the other beta-globin gene. This single nucleotide change abolishes a NcoI recognition site and hence it can be directly visualized after gel electrophoresis. Analyses of restriction fragment length polymorphisms showed that she also carried a rightward -3.7 kb (type I) deletion in her alpha-globin genes, and is in fact a alpha beta-thalassaemia genotype.