Septo-optic dysplasia with olfactory tract and bulb hypoplasia.

Optic nerve hypoplasia can be associated with other central nervous system malformations. When associated with absence of the septum pellucidum or thinning of the corpus callosum, it is termed septo-optic dysplasia. Considered to be a first trimester event, the embryologic timing and etiology of this syndrome still is not clearly defined. This report represents the first documented case of septo-optic dysplasia with associated hypoplasia of the olfactory tract. Optic nerve hypoplasia is attributed to an abnormal developmental process during gestation. Generally accepted to be due to a first trimester insult, the timing of this abnormality has been debated given its association with other central nervous system abnormalities. These central nervous system abnormalities often include cerebral hemispheric and hypothalmic-pituitary axis abnormalities. Specifically, the presence of optic nerve hypoplasia with absence of the septum pellucidum and thinning of the corpus callosum has been termed septo-optic dysplasia or de Morsier's syndrome. Septo-optic dysplasia in association with olfactory tract and bulb hypoplasia has not been reported previously.