The CLC‐7 Gly215Arg mutation reduces osteoclast activity by ∼80–90% [Henriksen et al., 2004; Schulz et al., 2010], and Clcn7 null (Clcn7−/−) mice develop severe OPT and retinal degeneration [Kornak et al., 2001], but are not reported to have RTA. This evidence concerns the gene CLCN7 and retinal degeneration.