COCH and deafness: The most frequent causative deafness gene was TMC1 (DFNA36) (3 cases), followed by the next tier of genes (2 cases each) (CDH23, COCH, SLC26A4, TMPRSS3, ATP1A3), and the genes that were detected only once (ACTG1, GJB2, ILDR1, MYO7A, MYO15A, NF2, NLRP3 and SERPNB6).