Co-inheritance of alpha+-thalassaemia and sickle trait results in specific effects on haematological parameters.

Both the sickle cell trait (HbAS) and alpha(+)-thalassaemia are common in many tropical areas. While their individual haematological effects are well described, few studies describe their effects when inherited together. We present data from the Kenyan coast, which suggest that HbAS and alpha(+)-thalassaemia may interact to produce specific effects on haematological parameters. Overall, the difference in Hb concentrations between non-thalassaemics (alpha alpha/alpha alpha) and alpha(+)-thalassaemia homozygotes (-alpha/-alpha) was greater in non-HbAS (HbAA) (0.63 g/dl) than in HbAS children (0.25 g/dl). HbAS also ameliorated both the reduced mean cell volume and mean cell haemoglobin normally associated with the -alpha/-alpha genotype. Potential mechanisms and implications are discussed.