CA2 and osteopetrosis: Previous studies demonstrated that 11 genes mutation, including TCIRG1, CLCN7, LRP5, IGSF23, OSTM1, CAII, PLEKHM1, TNFSF11, TNFRSF11A, CTSK, IKBKG and ITGB3 are reported to associate with osteopetrosis.