PI4K2A and Failure to thrive: It is notable that significant overlap exists in pathogenic variants in PI4KA and PI4K2A with phenotypes including severe combined NDD, epilepsy or even epileptic encephalopathy, brain malformation (hypomyelination/atrophy, corpus callosum abnormalities, pontocerebellar hypoplasia8), movement disorders (dystonia, spastic paraplegia), craniofacial dysmorphia, and feeding difficulties with failure to thrive (Fig. 3B).