Contribution of genetic factors to noise-induced hearing loss: a human studies review

Noise-induced hearing loss (NIHL) is a complex disease that results from the interaction of genetic and environmental factors. Over the last 10 years there has been a great increase in association studies trying to identify the susceptibility genes for NIHL in humans. They were conducted based on the candidate gene approach and comprised predominantly the group of oxidative stress genes, inner ear potassium recycling pathway genes and monogenic deafness genes, as well as other genes. So far, the most promising results were obtained for two genes encoding potassium ion channels (KCNQ4 and KCNE1), catalase (CAT), protocadherin 15 (PCDH15), myosin 14 (MYH14) and heat shock protein (HSP70), because they were replicated in two (Polish and Swedish) or three (Polish, Swedish and Chinese) populations, and were sufficient in size to yield high power for the detection of a causative allele. Today, the development of high-throughput genotyping methods allows the detection of hundreds and thousands of single nucleotide polymorphisms (SNPs) in a single array which undoubtedly will lead toward identification of new NIHL susceptibility genes. This in turn will contribute to the development of genetics tests that would allow for better protection of noise-exposed individuals and personalized treatment, if necessary.