[Genetics of specific language impairments]. / Les facteurs génétiques dans les troubles spécifiques du langage oral.

Specific language impairment (SLI), involving environmental as well as genetic factors, is a complex disorder affecting 5-10% of preschool-age children. This review summarizes current data regarding the genetic factors involved in SLI. Genetic factors were first implicated in SLI on the basis of twin studies and reports of familial cases. Furthermore, several studies have shown that the relative risk of SLI was higher for close relatives of affected individuals. Finally, a specific gene (FOXP2) has been identified on the long arm of chromosome 7 in a family affected with SLI, and several regions of the genome, i.e. 7q31, 16q and 19q, have been found to be strongly linked to SLI.