ATP1A3 and Global developmental delay: The expanding spectrum of ATP1A3 disease includes patients with features of both AHC and RDP having partial features of each or fulfilling the diagnostic criteria of both; (84, 85) or patients who share features with RDP or AHC but with distinct characteristics of the D-DEMØ phenotype - Dystonia, Dysmorphism of the face, Encephalopathy with developmental delay, MRI abnormalities of the brain always including cerebellar hypoplasia, No hemiplegia (Ø), and neonatal onset (86).