Indeed, the mutation resulted in an osteopetrosis that was as severe as in the ClC-7 KO mice but with milder neurodegeneration and no defect in pigmentation, suggesting that there was also a functional role for a transport-deficient ClC-7, for example, in contributing to the assembly of a lysosomal macromolecular complex [45]. Here, CLCN7 is linked to osteopetrosis.