This study describe a case of SNC malformation that belongs to the prosencephalization defects. Particularly, the degree of cerebral anomalies and the gravity of facial abnormalities place the case in the group of Holotelencephalies. We have considered the ethiopathogenetic connections that can cause such embryonic damage, the clinical characteristics, the evolution and the prognosis, by the light of the dates provided by literature. Our patient is a six month-old female put under observation since her birth.