TCIRG1 and osteopetrosis: TCIRG1 is well-documented in bone disorders: mutations in TCIRG1, account for over 50% of infantile malignant autosomal recessive osteopetrosis cases (Sobacchi et al., 2013), and its R740S mutation in mice disrupts proton pump function, inducing osteopetrosis and highlighting its key role in bone homeostasis (Ochotny et al., 2011).