The physiological relevance of CLC proteins is underscored by their involvement in various human genetic diseases, ranging from myotonia (ClC-1), kidney diseases (ClC-K, ClC-5), and osteopetrosis (ClC-7) to hyperaldosteronism (ClC-2), neurodevelopmental delay (ClC-3, ClC-4, ClC-6), and neurodegeneration (ClC-6, ClC-7) [1,6,7,8]. The gene discussed is CLCN7; the disease is osteopetrosis.