This is a disorder of brain development in which certain structures of the brain and the optic nerve are not fully developed. It is sometimes called de Morsier syndrome after Georges de Morsier, a Swiss neurologist, in 1962.
There is great variability of the clinical signs and symptoms among patients. Underdevelopment of the optic nerves that connect the eye to the brain is the only ocular feature but it causes reduced vision and sometimes nystagmus (‘dancing eyes’) and crossing of the eyes are the result. It is usually unilateral but may occur bilaterally.
The major systemic findings are that of deficient hormones of various types resulting from maldevelopment of the pituitary gland. This is often associated with absence of certain brain structures known as the septum pellucidum and the corpus callosum. Some individuals have more severe brain malfunction resulting in mental retardation or manifestations of the autism spectrum disorders. Other patients can have abnormalities of the fingers and toes such as fusion or underdevelopment. Short stature and abnormal sexual maturation are sometimes present.
Most cases occur sporadically, that is, with no family history, and it is likely that this disorder consists of several disorders. In rare families in which multiple cases are found, a gene mutation has been found which is present in a double dose. This suggests that a gene mutation with an autosomal recessive mode of inheritance as one cause of septooptic dysplasia.
The diagnosis often requires a collaborative effort by ophthalmologists, radiologists, and endocrinologists. All individuals with underdeveloped optic nerves should have a full evaluation by these specialists to diagnose and treat the hormone deficiencies which can be life-threatening. No treatment is available for the optic nerve malformation but low vision aids could be helpful for those individuals with bilateral disease. Special education should be considered for children with cognitive defects. With proper hormone supplementation, a normal lifespan and a productive life are possible.