Frequency of deletional types of alpha-thalassemia in Kampuchea.

The frequency of deletional types of alpha-thalassemias in the Khmer population of Kampuchea (Cambodia) was estimated using DNA techniques. Among 58 healthy adult Kampucheans from rural areas, 17 had alpha-globin gene anomalies. There were 14 heterozygotes and two homozygotes for alpha(+)-thalassemia; the remaining test subject carried a deletion of both alpha-globin genes (alpha(0) -thalassemia of the Southeast Asian type) on one chromosome 16, and triple alpha-globin genes on the other. All of the 18 alpha(+)-thalassemia deletions were of the -alpha 3.7 type (17 subtype I, 1 subtype II). The restriction pattern obtained with the enzyme RsaI and comparison of the intensity of hybridization with alpha-globin and beta-globin gene probes yielded no evidence of total deletion of the alpha-gene complex. The prevalence of deletional alpha(+)-thalassemia in Kampuchea is higher, and that of alpha(0)-thalassemia is lower than in neighbouring Thailand.