[Genetic aspects of congenital sensorineural hearing loss]

Hearing loss is the most common sensory disability with an incidence of one over 1000 newborns. Hearing loss may be caused by environmental and genetic factors; inherited causes are assumed in two thirds of cases. There is a great clinical and genetic heterogenicity. All inheritance modes have been described. Mutations in the GJB2 gene, which encodes connexin 26, are mainly responsible for sensorineural deafness resulting in prelingual non syndromic autosomal recessive phenotypes DFNB1. The 35 delG mutation of this gene is very frequent (70% of the cases). Thus, 35 delG is, with the delta F508 mutation of the CFTR gene, the most frequent human pathogenic mutation known. Hearing loss might also be associated with other clinical features. Some of these syndromes, including hearing loss, have to be looked for systematically because of their frequency, of their possible clinical presentation as an isolated hearing loss and of the possibility of a medical treatment.