GRXCR2 and hearing loss disorder: To gain insight into the mechanisms by which mutations in Grxcr2 cause hearing loss, we used the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system to introduce mutations in exon 1 of Grxcr2. Two new alleles were generated, bearing 46-bp (Grxcr2D46/D46) and 85-bp (Grxcr2D85/D85) deletions in exon 1.