Septo-optic dysplasia (SOD) is a disorder of early brain development with a variable phenotype. The diagnosis of this disorder is established by the presence of any combination of optic nerve hypoplasia, pituitary gland hypoplasia, and midline brain abnormalities. The brain abnormalities include absence of the corpus callosum and septum pellucidum (Dattani, 1998). About one-third of people diagnosed with septo-optic dysplasia have all three major features; most affected individuals have two of the major features. Mutations in the HESX1 gene have also been identified in patients with combined pituitary hormone deficiency without other abnormalities being present (Sobrier, 2006).