2008) as well as a novel 5‐bp duplication in the DPP coding region of DSPP (c.3504_3508dup; p.Asp1170Alafs*146) that would have generated −1 reading frameshift of the type known to cause inherited dentin defects (McKnight et al. 2008b). This is the first novel disease‐causing DSPP mutation identified by SMRT sequencing and in this case helped to establish the diagnosis as being DGI‐II, rather than OI. This evidence concerns the gene DSPP and dentinogenesis imperfecta.