GSTM1 and noise induced hearing loss: For the last two decades, several genetic studies were performed to identify the NIHL susceptibility genes and among them various NIHL susceptibility genes have been known to involved in different cellular pathways such as the genes involved in the potassium recycling pathway (Kcnq1, Kcnq4, kcne1, Kcnj10, Gjb1, Gjb2, and Gjb4) [51, 52], oxidative stress gene (Sod2, Cat, Gstm1, and Pon2) [53, 54], heat shock protein genes (Hsp70) [55], and monogenic deafness genes (Myh14 and Pcdh15) [56].