SummaryThe 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.