COL2A1 and spondyloepiphyseal dysplasia congenita: Eighteen variants of COL2A1 were reported to cause SEDC in Chinese including our patients, all of which were missense variants and affected the Gly‐X‐Y triple‐helical region (Cao et al., 2012; Chung et al., 2013; Huang et al., 2015; Li et al., 2014, 2015; Liu et al., 2016; Xiong et al., 2018; Xu et al., 2014; Zhang, He, Fu, Zhang, & Zhang, 2011).