SH3BP2 and Osteopenia: Missense mutations in SH3BP2 have been identified as cause for the autosomal dominant form of CBM.(5) CBM mutations protect SH3BP2 protein from tankyrase‐mediated degradation leading to SH3BP2 accumulation and increased proto‐oncogene tyrosine‐protein kinase, spleen tyrosine kinase, PLCγ1/γ2 (Phospholipase C gamma 1/2), and vav Guanine nucleotide exchange factor signaling.(6, 7, 8, 9) Studies of knockin (KI) mice expressing mutant SH3BP2 protein (P416R or G418R) showed that Sh3bp2KI/KI mice develop osteopenia, and autoinflammatory lesions in long bones, craniofacial bones, and soft tissues.