Enhanced haemolysis with β-thalassaemia trait due to the unstable β chain variant, Hb Gunma, accompanied by hereditary elliptocytosis due to protein 4•1 deficiency in a Japanese family

We identified a Japanese family with a beta-thalassaemia trait and hereditary elliptocytosis (HE). We studied five members of this family. One was normal, one had only the beta-thalassaemia trait, one had heterozygous HE, and two had compound heterozygous beta-thalassaemia trait and HE. The last two had already undergone splenectomy. The molecular profile of beta-thalassaemia was consistent with that of Hb Gunma: codon 127/128CAGGCT(Gln-Ala)--> CCT(Pro). Analysis of erythrocyte membrane proteins revealed a partial deficiency of protein 4.1 in all those with HE, whereas the spectrin content was within the normal range. Each heterozygous family member with either the beta-thalassaemia trait or HE was asymptomatic, whereas the two with both beta-thalassaemia and HE had marked red blood cell deformities and haemolysis. The abnormalities of the red blood cells in patients with the beta-thalassaemia trait might be enhanced by association with HE owing to a protein 4.1 deficiency.