Hb Icaria–Hb H disease: identification of the Hb Icaria mutation through analysis of amplified DNA

Abstract

Summary Hb Icaria–Hb H disease was observed in a Yugoslavian teenager who exhibited moderate anaemia with severe microcytosis and hypochromia and 16% Hb H. Four of his relatives were Hb Icaria heterozygotes; their haematological data were comparable to those with a deletional type of α‐thalassaemia‐2. The patient also had an additional α‐thalassaemia‐1 deletion, an ∼20.5 kb deletion, common among Mediterranean populations. The Hb Icaria mutation, i.e. the TAAÁA mutation at codon 142, was identified by hybridization of amplified DNA with specific probes. The mutation is located on the α 2 ‐globin gene; the one remaining α 1 ‐globin gene is apparently able to compensate sufficiently for the loss of the three α‐globin genes to maintain a haemoglobin level of 8–9 g/dl.