Thalassemia in the West Indies.

U NTIL comparatively recently thalassemia was thought to be confined predominantly to persons of Mediterranean origin. it is now abundantly clear that it has a world-wide distribution1 being particularly prevalent in the Far East.2 Reports from Africa ,4 point to the possibility that thalassemia may occur with considerable frequency in the Negro. In addition there is strong evidence that thalassemia is not a homogeneous entity and indeed it may have arisen from independent and different mutations. In Jamaica the population is mainly Negro with some Caucasian admixture originating predominantly from Great Britain. From the end of the nineteenth century some Indian and Chinese immigration has taken place. With such a composite population it is not surprising that with detailed studies thalassemia was soon discovered, both in combination with the sickle cell gene#{176}’T and in the form of thalassemia major. About half the thalassemia genes which we have seen so far originated from Chinese elements in the population, the other half came from Negroes in whom however some Caucasian admixture cannot be completely excluded. In this paper we report our experience of thalassemia in Jamaica, discuss the criteria for its diagnosis and emphasize the inherent difficulties involved in studies of this condition. Evidence is given for the heterogeneity of thalassemia.