Genetic factors in noise induced hearing loss

At present, our knowledge of the genetic factors that are responsible for noise induced hearing loss (NIHL) is still limited, especially compared with the relatively well-studied environmental factors. Nevertheless, there is mounting evidence that several genetic mutations could determine an individual and intrinsic predisposition to noise damage. An important contribution to the study of genetic factors in NIHL derives from laboratory research on genetically modified animals. To date, three loci that contribute to NIHL, have been identified in these strains of mice 10 that contribute to age-related hearing loss, and six loci that promote both. Experimental data obtained in mice have been found and confirmed in humans. The cross-talk between studies in humans and those in model organisms is essential in this field. Genetic polymorphism in several candidate genes showed significant differences between vulnerable and resistant subjects selected among populations of workers exposed to occupational noise. In theory, any gene that weakens the ear functionally or structurally would make it more susceptible to noise damage. The identification and isolation of these genetic factors could have important and practical outcomes. For example, workers genetically predisposed should be more strictly protected against noise, compared with what is requested by actual legislation, which is regulated on the basis of normal worker populations.