CLCN7 and osteopetrosis: Herein, we utilized the liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis to investigate the metabolic differences between healthy controls (HC) and osteopetrosis patients caused by CLCN7 mutation, help decipher the primary metabolic pathway(s) that were altered in osteopetrosis and provide potential more specific and sensitive biomarkers.