Atypical HbH disease in a Surinamese patient resulting from a combination of the -SEA and -alpha(3 center dot 7) deletions with HbC heterozygosity

The first case of haemoglobin H (HbH) disease in combination with haemoglobin C (HbC) is reported in a man of Surinamese origin. Only haemoglobin A (HbA) and HbC were detected by electrophoresis. The amount of HbC was much less than expected in HbC heterozygotes. The synthesis ratio (beta(A)+beta(C)/alpha) indicated an alpha-thalassaemia defect with two non-functional alpha genes, which did not correlate with the degree of haemolysis and anaemia displayed by the patient. The DNA analysis of the alpha-genes clusters revealed a defect combination -SEA/-alpha(3.7). The haematological data and the physiopathology of this atypical case are compared with the typical HbH disease found in a first cousin of the propositus. Data on the globin chains expression and on the formation of beta(A) and beta(C) homotetramers in HbH/HbC disease are presented.