Anthropological approach to the heterogeneity of beta-thalassemia mutations in northern Africa.

Results of an epidemiological survey for beta-thalassemic defects involving 239 chromosomes in Algeria are analyzed in relation to the geographic and historical background of the country and are compared with published series for the Tunisian population. Four common mutations account for 81% of the chromosomes, but 13 other defects have been found, illustrating the highly heterogeneous nature of the disease in the northern African countries of the Maghreb. The high frequency of homozygous cases reflects the endogamous social structure of these populations. Distribution of the mutations and linkage to specific RFLP haplotypes provide information concerning their origin and date of introduction in good correlation with the anthropological history of Algeria.