It is interesting to note that the symptoms associated with SMD, for example, caused by NEK1 or C21ORF2 mutations, are somewhat reminiscent of the SPONASTRIME syndrome caused by mutations in TONSL that weaken HR (Burrage et al, 2019; Chang et al, 2019). This evidence concerns the gene NEK1 and spondyloepimetaphyseal dysplasia, Strudwick type.