Although developmental delay (DD) was reported in 33% of SHFM1 patients (Elliott and Evans, 2006), the abnormality was restricted to large deletions or translocations of which at least one breakpoint was mapped outside the SHFM1 locus (Haberlandt et al., 2001; Bernardini et al., 2008; Saitsu et al., 2009; van Silfhout et al., 2009; Brown et al., 2010; Vera-Carbonell et al., 2012; Delgado and Velinov, 2015; Sivasankaran et al., 2016; Rai et al., 2019). This evidence concerns the gene SEM1 and dentin dysplasia.