De Morsier Syndrome
The Common Vein Copyrighrt 2010
De Morsier syndrome is a neurological entity in which there is an absence or hypoplasia of the septum pelucidum along with hypoplasia of one or both optic nerves and a dysfunction of the hypothalamic-pituitary function.
It is a rare and inherited disease, caused by genetic mutation, possibly in the HESX1.4 gene.
Clinically, hypoplastic optic nerves are manifested by symptoms ranging from slight decrease in visual acuity or complete blindness. Patients can have visual field defects , impaired depth perception, photophobia and nystagmus. Apart from that, there is often mental retardation, and also seizures and cerebral motor disease. Hypothalamic and pituitary defects are initially most striking with growth hormone deficiency. Diabetes insipidus is also frequent. It can also result in precocious puberty, hypogonadism, seconday adrenal insufficiency and secondary hypothyroidism.
Neuroimaging findings include absence of the septum pellucidum, agenesis of corpus callosum, cerebellar atrophy, ventricular dilatation and lipomas or brain cysts. There may be an ectopic or hypoplastic neurohypophysis. The absence of septum pellucidum is easily visualized by ultrasound, CT or MRI, although the latter is the technique of choice.
There is no treatment for the condition; prognosis depends on the degree of affected structures, though generally carries a good prognosis, though it is worse if the hypothalamic-pituitary axis is affectted.