PHF21A is part of a transcriptional complex regulating neuronal gene expression and its mutations or deletions have been associated with NDD [41]; intriguingly, the two deletions encompass part of CREB3L1, a gene which is, itself, not linked to NDD, and not highly expressed in neural cells according to the Human Protein Atlas Database [42]. The gene discussed is PHF21A; the disease is Neurodevelopmental delay.