Thus, deficiency in GALNT2 is characterized by global developmental delay, intellectual disability, behavioral abnormalities, epilepsy, autistic features, chronic insomnia, decreased stature, white matter lesions in brain magnetic resonance scans, and dyslipidemia (33), phenotypes that are partially recapitulated in a pan-neuronal Galnt2 knock-out mouse (44). Here, GALNT2 is linked to Global developmental delay.