Septo-optic dysplasia

Septo-optic dysplasia (SOD), known also as de Morsier syndrome, is a rare congenital malformation syndrome that features a combination of the underdevelopment of the optic nerve, pituitary gland dysfunction, and absence of the septum pellucidum (a midline part of the brain). Two or more of these features need to be present for a clinical diagnosis — only 30% of patients have all three. [Source: Wikipedia ]

Absent or hypoplastic septum pellucidum
OrphaNet reference
Septo-optic dysplasia 
May Cause
Abnormal configuration of cerebral ventricles
Congenital brain malformation