Mice with complete ClC-2 knockout or homozygous ClC-2 truncation mutation exhibited a dramatic loss of retinal photoreceptors and male germ cells, leading to blindness and male infertility, respectively (Bosl et al. 2001, Nehrke et al. 2002, Edwards et al. 2010). The gene discussed is CLCN2; the disease is male infertility.