KCNQ3 and developmental disability: Heterozygous pathogenic variants in KCNQ3 have been associated with neonatal‐onset epilepsies showing broad clinical heterogeneity and diverse genetic transmission mechanisms.16 These range from relatively benign familial phenotypes with seizures starting in the neonatal (BFNS)6, 12, 13 or early‐infantile (BFIS)14, 15 period, to sporadic cases with severe clinical presentations characterized by developmental disabilities with or without refractory seizures17, 19, 21, 22, 49 or by cortical visual impairment.23