GPX6 and hearing loss disorder: Statistical computations comparing the signal log ratios (Table 1) and fold changes of middle age, old mild hearing loss, and old severe hearing loss subject groups showed significant differences in expression or large fold-changes for four genes: Gpx6, Txnrd1, Idh1, and Hspb1. These gene expression changes were selected for validation by using real-time PCR (qPCR).