CTSK and osteopetrosis: Previous studies showed the genes mutation of TCIRG1, CLCN7, LRP5, IGSF23, OSTM1, CAII, PLEKHM1, TNFSF11, TNFRSF11A, CTSK, IKBKG and ITGB3 have been shown to be associated with osteopetrosis or osteopetrosis‐like phenotypes.10 However, none of these mutations was detected in this study, which indicates a novel gene mutation may emerge.