First, mutations in the C21ORF2 gene phenocopy NEK1 mutations in Jeune syndrome, SMD, and ALS (van Rheenen et al, 2016; Wang et al, 2016; McInerney-Leo et al, 2017); this pattern of similarity is unique, suggesting that the functions of these two genes are intimately linked. This evidence concerns the gene NEK1 and spondyloepimetaphyseal dysplasia, Strudwick type.