Besides, de novo variants in both ATN1 and RERE seem to perturb the HX-repeat motif of the atrophin 1 domain (Fig. 3g), causing congenital anomalies such as hypotonia, epilepsy and developmental delay (Fregeau et al. 2016; Palmer et al. 2019), which further indicates a link between their functions. The gene discussed is ATN1; the disease is Global developmental delay.