A new beta-thalassaemia frameshift mutation detected by PCR after selective hybridization to immobilized oligonucleotides.

A previously undescribed mutation (-1, +3, codon 24) causing beta-thalassaemia was identified in an Egyptian patient. It consists in the concomitant deletion of a G in codon 24 and its replacement with the new trinucleotide CAC, thus resulting in the shift of the beta-globin reading frame. The sequence of the chromosome of interest was isolated from the homologous one by means of selective hybridization to an immobilized oligonucleotide. The presence of this mutation in the proband's family was confirmed by dot blot hybridization with an oligonucleotide probe.