Gene Linked to Age-Related Hearing Loss

his masters voiceHearing loss is one of the most common conditions affecting older adults; more than half of people over the age of 60 are hard of hearing or deaf. The causes of age-related hearing impairment, also known as prebycusis, have not been fully established but it is known that the condition seems to run in families. Now a whole genome association study has linked GRM7, the gene encoding metabotropic glutamate receptor type 7 (mGluR7), with prebycusis. The study, published in Human Molecular Genetics identified variants in GRM7 in individuals with hearing loss. Follow-up histochemical studies in human and mouse showed that mGluR7 is expressed in hair cells and spiral ganglion cells of the inner ear. The data link common alleles of GRM7 to an individual’s risk of developing prebycusis, possibly by altering susceptibility to glutamate excitotoxicity. The identification of a genetic cause for age-related hearing loss could lead to the development of treatments for the condition, although the next step will be to develop an animal model to test potential treatments.