Thalassaemia in northern Liberia. A survey in the Mount Nimba area.

A population survey in northern Liberia showed an average incidence of 9 percent of beta-thalassaemia trait. There was considerable tribal variation, the highest rates being mainly found in tribes having a low incidence of Hb S. A single example of deltabeta-thalassaemia trait was also found; the incidence of delta-chain variants was 1.8 percent. The effect of malaria on Hb A2 levels was investigated but appeared to be negligible. The problems of beta-thalassaemia and Hb S occurring in the same population are discussed. It is considered that, although made on a local sample, the results of this survey indicate a high incidence of beta-thalassaemia trait elsewhere in Liberia and that this is a suitable are for investigations of linkage at beta- and delta-chain loci. No conclusion is at present possible from the data on the presence of alpha-thalassaemia although 10 percent of neonates were found to have increased levels of Hb Barts.