Lysosomal Ca2+ release may be a key factor in the pathogenesis of ClC-7-associated osteopetrosis, since osteoclasts lacking ClC-7 (ClC-7ko) or expressing an uncoupled ClC-7 mutation (ClC-7unc) present underdeveloped ruffled borders [47,53], likely due to decreased lysosomal exocytosis, a process involving lysosomal Ca2+ release. The gene discussed is CLCN7; the disease is osteopetrosis.