TMC1 may be a common gene for nonsyndromic hereditary hearing loss in Indian population

Background Hearing impairment is very heterogeneous and most common sensory disorder. The prevalence of prelingual hearing loss is 1:500, with both environmental and genetic factors being equally responsible. To date, more than 128 loci and 74 genes responsible for nonsyndromic hereditary hearing loss have been identified, of which GJB2 gene is the most common across populations. Transmembrane channel like 1 or transmembrane cochlear-expressed gene 1 (TMC1) at DFNB7/11 locus at 9q13–q21 is another gene that is responsible for prelingual, severe to profound hearing impairment. It contains 24 exons and encodes 760 amino acids long 87.8 kDa multipass transmembrane protein, which is required in maintaining electrochemical homeostasis, structure and function of neurosensory hair cells in the inner ear. More than 29 different mutations have been reported in 48 families.