Septo-optic Dysplasia

Definition

Septo-optic dysplasia (SOD) is a rare, congenital disorder. Findings include optic nerve hypoplasia with a thin or absent septum pellucidum and/or corpus callosum and pituitary dysfunction. Optic nerve hypoplasia is mandatory for the diagnosis of SOD.

Description

SOD also known as DeMorsier's syndrome is a combination of optic nerve underdevelopment (hypoplasia) with abnormalities of a part of the brain called the septum pellucidum and/or corpus callosum. Endocrine disorders such as dwarfism, decreased thyroid gland function (hypothyroidism), dehydration, delayed or precocious puberty and reduced blood sugar may occur from dysfunction of the pituitary gland of the brain. SOD has also been associated with congenital architectural brain anomalies.

Causes and symptoms

The cause of SOD is thought to be related to intrauterine viral infections or diabetes during pregnancy. Antiseizure medications, alcohol and illicit drugs have also been linked to SOD. In addition vascular abnormalities and uncommonly genetics are thought to play a role.

Patients afflicted with SOD can present at any age depending on the severity of the symptoms. Signs and symptoms such as failure to thrive, prolonged jaundice, body temperature dysregulation, decreased blood sugar, small genitalia or muscular flaccidity can herald the diagnosis of SOD in newborns.

Older children may complain of visual difficulties and be found to have strabismus (crossed eyes), nystagmus (involuntary, jerky eye movements) or inability to fixate on an object. In addition pupillary and color vision abnormalities may be noted. The optic nerves will appear small and grey or pale in color and can be surrounded by a yellowed halo signifying hypoplasia or atrophy.

A large percentage of SOD patients will have endocrine disorders. By far growth hormone deficiencies are the most common in patients with optic nerve hypoplasia. Growth hormone deficiency can lead to reduced blood sugar, while abnormal levels of reproductive hormones can result unusual pubertal development. Reduced levels of thyroid-stimulating hormone will cause suboptimal thyroid gland functioning (hypothyroidism). Other endocrine problems include increased urination, dehydration and death.

In some instances patients will have behavioral and cognitive problems resulting from brain maldevelopment or endocrinologic disorders.

Diagnosis

Suspicion for the diagnosis of SOD is based on clinical findings described above. In addition magnetic resonance imaging (MRI) of the brain focusing on the visual pathways, hypothalamus-pituitary region and other mid-line structures and septum pellucidum is invaluable for solidifying the diagnosis.

Treatment team

Pediatricians, endocrinologists, optometrists, ophthalmologists, neuro-ophthalmologists and neurologists can all contribute to patient care.

Treatment

SOD is treated symptomatically. Hormone deficiencies are managed with hormone replacement therapy while the best possible visual acuity is achieved with corrective spectacle lenses.

Recovery and rehabilitation

Patients with extremely poor vision may benefit from a low vision specialist. He or she may be able to prescribe a visual apparatus to maximally improve visual function.

Special concerns

Patients with severe visual depression may have difficulty obtaining a driver's license or gainful employment.

BOOKS

Liu, Grant T., Nicholas J. Volpe, and Steven L. Galetta. Neuro-Ophthalmology Diagnosis and Management, 1st ed. Philadelphia, PA: W. B. Saunders Company, 2001.

PERIODICALS

Campbell, Carrie. "Septo-optic dysplasia: a literature review." Optometry 72, no. 7 (July 2003): 417-426.

ORGANIZATIONS

National Organization for Rare Disorders. PO Box 1968, Danbury, CT 06813-1968. 202-744-1000 or 800-999-NORD; Fax: 203-798-2291. orphan@rarediseases.org. <http://www.rarediseases.org>.

National Eye Institute. National Institute of Health, Bldg. 31, Rm. 6A32, Bethesda, MD 20892-2510. 301-496-5248. 2020@b31.nei.nih.gov. <http://www.nei.nih.gov>.

Adam J. Cohen, MD