Certain uncommon genetic disorders occur relatively frequently in the various population groups of Southern Africa. Prominent among these are porphyria, colonic polyposis and sclerosteosis in the Afrikaner community, Huntington's chorea in the British, Gaucher's and Tay-Sachs diseases in the Jewish population, glucose-6-phosphate dehydrogenase deficiency (G-6-PD deficiency) and thalassaemia in the Greek community, various skeletal dysplasias in the Black group, lipoid proteinosis and cleidocranial dysostosis in the Cape Coloured population, diabetes mellitus in the Indian community and retinitis pigmentosa in the Tristan da Cunha islanders. In addition, 'private' syndromes have been encountered in virtually every group. Awareness of the ethnic distribution of unusual genetic conditions is of considerable practical importance during the differential diagnosis of obscure disease.
Following the suggestion that it was possible that cases of melioidosis amongst those who had been exposed abroad in the past, might be escaping notice, 487 Royal Marines were examined by indirect haemagglutination studies. Four hundred and eleven of these subjects had served for variable times in areas where melioidosis has been known to occur in Indonesia and Malaya, between 1960 and 1974, occupied in activities in the jungle and paddy fields during which exposure to the disease was to be expected. No evidence of residual subclinical melioidosis was found and it seems unlikely that recrudescent disease will prove to be a problem in the future for English servicemen who have been in South East Asia.