Genetic diseases in the Tunisian population.

Tunisia is one of the North African countries, geographically situated in a central position at the crossroad between Africa and Europe. The demographic features of the Tunisian population include among others high rates of consanguinity. We report, here on the spectrum of genetic diseases in Tunisia. The review of the literature, including other available information (gray literature) showed that there are at least 346 genetic disorders for which cases have been identified in the Tunisian population. Among these, 62.9% are autosomal recessive, 23% autosomal dominant, 5.4% X-linked, and the remaining are of Y-linked, mitochondrial, and unknown mode of transmission. Fifty percent of the reported conditions in this study are caused by at least one mutation. For autosomal recessive diseases, most of the mutations were identified at homozygous state among the affected individuals. Part of the mutations was the result of a founder effect; these are the consequences of the high rate of consanguinity. The congenital malformations, diseases of the nervous system and metabolic disorders are the major groups of genetic diseases affecting the Tunisian population. The large spectrum of diseases and their relatively high frequency could be explained by the high degree of inbreeding and the presence of multiple mutations, either allelic or in different genes. This is due to the richness of the genetic background of the studied population. A multidisciplinary approach is essential to develop adequate preventive programmes adapted to the social, cultural, and economic context. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]