Other studies indicated that the most frequent variant of p.Arg989Cys in COL2A1 led to severe skeletal dysplasia, and glycine‐to‐serine substitutions were associated with mild SEDC (Silveira et al., 2015; Steplewski et al., 2004). This evidence concerns the gene COL2A1 and spondyloepiphyseal dysplasia congenita.