CLCN7 and autosomal recessive osteopetrosis: For example, most of the known forms of OC-rich autosomal recessive osteopetrosis (ARO) have been linked to mutations in subunits of the multimolecular vacuolar-ATPase (V-ATPase) proton pump and chloride voltage-gated channel 7 (CLCN7), both indispensable components of the OC acidification machinery as described herein.