Hb Hinwil [beta38(C4)Thr-->Asn, ACC>AAC] associated with beta0-thalassemia in a Sicilian child

Hemoglobins (Hbs) with high oxygen affinity play a well-known role among the causes of erythrocytosis. In 1996, a new Hb called Hb Hinwil or beta38(C4)Thr-->Asn was described. In carriers, it causes an increase in the number of red blood cells, total Hb, and hematocrit. Here we report the case of a patient, aged 10 months, whom we observed because of severe erythrocytosis. The family history of beta-thalassemia (beta-thal) inheritance, and the evidence in the patient of marked microcytosis, prompted us to perform molecular analysis to detect beta gene mutations that revealed a codon 39 (C>T) (beta0) mutation in the heterozygous state and the presence of the Hb Hinwil mutation on the other allele. We discuss diagnostic, clinical, prognostic, and therapeutic aspects of this rare condition, underlining the extreme difficulty in choosing therapeutic options because of a lack of similar reports in the literature.