Beta-thalassaemia intermedia due to a complex alpha-globin rearrangement and a heterozygous beta thalassaemia mutation.

The alpha-thalassaemia alleles are very frequent in the world's population. The main molecular mechanism is a large deletion with the loss of one or two alpha genes. Another type of rarer abnormality exists: the gain of alpha genes. The consequence of a gain is an overproduction of alpha-globin chains, which aggravates a beta-thalassaemia trait into an intermedia phenotype (non-transfusion-dependent thalassaemia, NTDT). Here, we report the case of a young girl referred for a beta-NTDT with a combination never described in the literature: a heterozygous beta-thalassaemia mutation associated with a copy number gain of the alpha-globin locus and -alpha 3.7 deletion on the same allele.