Mutation analysis of TMC1 identifies four new mutations and suggests an additional deafness gene at locus DFNA36-DFNB7/11

Hearing loss is the most frequent sensorineural disorder, affecting 1 in 1000 newborns. In more than half of these babies, the hearing loss is inherited. Hereditary hearing loss is a very heterogeneous trait, with about 100 gene localizations and 44 gene identifications for nonsyndromic hearing loss. TMC1 has been identified as the disease-causing gene for autosomal dominant and autosomal recessive nonsyndromic hearing loss at the DFNA36 and DFNB7/11 loci, respectively. To date, two dominant and 18 recessive TMC1 mutations have been reported as the cause of hearing loss in 34 families. In this report, we describe linkage to DFNA36 and DFNB7/11 in one family with dominant and 10 families with recessive nonsyndromic sensorineural hearing loss. In addition, mutation analysis of TMC1 was performed in 51 familial Turkish patients with autosomal recessive hearing loss. TMC1 mutations were identified in seven of the families segregating recessive hearing loss. The pathogenic variants we found included two known mutations, c.100C>T and c.1165C>T, and four new mutations, c.2350C>T, c.776+1G>A, c.767_768del and c.1166G>A. The absence of TMC1 mutations in the remaining six linked HHS Public Access Author manuscript Clin Genet. Author manuscript; available in PMC 2016 January 29. Published in final edited form as: Clin Genet. 2008 September ; 74(3): 223–232. doi:10.1111/j.1399-0004.2008.01053.x. Author Manuscript families implies the presence of mutations outside the coding region of this gene, or alternatively, at least one additional deafness-causing gene in this region. The analysis of copy number variations in TMC1 as well as DNA sequencing of 15 additional candidate genes did not reveal any proven pathogenic changes, leaving both hypotheses open

sensorineural disorder