Boonsawat’s team reported on a patient with DD who had a TRAPPC9 variant (c.3214C>T, p. Arg1072*), which led to altered neuronal NF-kappa-B signaling and was associated with moderate to severe GDD, mild cortical atrophy, and delayed myelination (Boonsawat et al., 2019). The gene discussed is TRAPPC9; the disease is dentin dysplasia.