Osteoclast-rich osteopetrosis is caused by mutationsin genes responsible for lacunar acidification, resorptionand pH regulation (TCIRG1, CLCN7, OSTM1 and CAII ),vesicular transport and sorting of protein complexes to themembrane (SNX10 and PLEKHM1), lysosomal nucleosidetransport (SLC29A3) cytoskeletal rearrangement for“corrugated edge” formation (KINDLIN3, integrin-β andLRRK1) and lysosomal proteolytic cleavage for bone remodelingand resorption (CTSK), for signal transductionand osteoclast function (MITF, TRAF6, RELA and NEMO)(De Cuyper et al., 2021; Penna et al., 2021). The gene discussed is OSTM1; the disease is osteopetrosis.