This observation could offer a molecular explanation for the described linkage of mGluR7 to age-related hearing-impairment and noise-induced hearing-loss [82,83,85,86,87]—after sound waves pass the oval window, they form a travelling wave along the tonotopic axis of the cochlea, with higher frequencies represented at the base and lower frequencies encoded towards the apex. Here, GRM7 is linked to hearing loss disorder.