A rare beta-thalassaemia mutation (C-T) at position -90 of the beta-globin gene discovered in a Chinese family.

We provide the first description of a Chinese family with three heterozygotes for a rare beta-thalassemia mutation previously observed in a Portuguese carrier. The mutation (-90 C-T) changes the conserved promoter sequence within the proximal CACCC box of the beta-globin gene; this can reduce beta-globin transcription significantly.