ACAN and skeletal dysplasia: This study focused on exploring phenotype and genotype in seven families with SEMD caused by TRPV4, SBDS, COL2A1, CCN6, and ACAN gene mutations, including two TRPV4-related skeletal dysplasia, one spondyloepiphyseal dysplasia, one Kniest dysplasia, one progressive pseudorheumatoid dysplasia, one Shwachman–Bodian–Diamond syndrome, and one aggrecan-related SED.