Septo-optic dysplasia is a disorder of early brain development. Although its signs and symptoms vary, this condition is traditionally defined by three characteristic features: underdevelopment (hypoplasia) of the optic nerves, abnormal formation of structures along the midline of the brain, and pituitary hypoplasia.

The first major feature, optic nerve hypoplasia, is the underdevelopment of the optic nerves, which carry visual information from the eyes to the brain. In affected individuals, the optic nerves are abnormally small and make fewer connections than usual between the eyes and the brain. As a result, people with optic nerve hypoplasia have impaired vision in one or both eyes. Optic nerve hypoplasia can also be associated with unusual side-to-side eye movements (nystagmus) and other eye abnormalities.

The second characteristic feature of septo-optic dysplasia is the abnormal development of structures separating the right and left halves of the brain. These structures include the corpus callosum, which is a band of tissue that connects the two halves of the brain, and the septum pellucidum, which separates the fluid-filled spaces called ventricles in the brain. In the early stages of brain development, these structures may form abnormally or fail to develop at all. Depending on which structures are affected, abnormal brain development can lead to intellectual disability and other neurological problems.

The third major feature of this disorder is pituitary hypoplasia. The pituitary is a gland at the base of the brain that produces several hormones. These hormones help control growth, reproduction, and other critical body functions. Underdevelopment of the pituitary can lead to a shortage (deficiency) of many essential hormones. Most commonly, pituitary hypoplasia causes growth hormone deficiency, which results in slow growth and unusually short stature. Severe cases cause panhypopituitarism, a condition in which the pituitary produces no hormones. Panhypopituitarism is associated with slow growth, low blood glucose (hypoglycemia), genital abnormalities, and problems with sexual development.

The signs and symptoms of septo-optic dysplasia can vary significantly. Some researchers suggest that septo-optic dysplasia should actually be considered a group of related conditions rather than a single disorder. About one-third of people diagnosed with septo-optic dysplasia have all three major features; most affected individuals have two of the major features. In rare cases, septo-optic dysplasia is associated with additional signs and symptoms, including recurrent seizures (epilepsy), delayed development, and abnormal movements.

What is septo-optic dysplasia?

Septo-optic dysplasia (SOD), previously known as de Morsier syndrome, is a rare disorder of development that involves the septum pellucidum—the thin membrane located between the two cerebral hemispheres (halves of the brain)—as well as the eyes and the pituitary gland. 

SOD causes optic nerve abnormalities and affects the optic disc located at the back of the eye, where the optic nerve meets the retina. The pituitary gland produces hormones that regulate other bodily functions. In people living with SOD, the septum pellucidum may be missing. 

Symptoms include:

• Loss of eyesight in one or both eyes
• Pupils that get bigger in the light
• An uncontrollably fast side-to-side movement of the eyes
• Eyes that turn towards or away from the nose

• Poor muscle tone
• Problems with hormones (chemicals in the body)
• Development delays from eyesight or neurologic problems

Symptoms are different for each person. Treatment focuses on the symptoms. Some people may need physical, vision, and occupational therapy.

How can I or my loved one improve care for people with septo-optic dysplasia?

Consider participating in a clinical trial so clinicians and scientists can learn more about SOD and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease. 

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

• Blindness in one or both eyes
• Pupil dilation in response to light
• Nystagmus (a rapid, involuntary to-and-fro movement of the eyes)
• Inward and outward deviation of the eyes
• Hypotonia (low muscle tone)
• Seizures

• Short stature due to lack of growth hormone deficiency (the most common hormonal abnormality)
• Abnormal thirst, hunger, and body temperature due to underdevelopment of the hypothalamus, a region of the brain responsible for regulating basic body functions.
• Low blood sugar
• Genital abnormalities
• Problems with sexual development or precocious puberty
• Sleep difficulties
• Obesity
• Jaundice
• Intellectual disability or learning disabilities
• Developmental delay related to vision impairment or neurological problems
• Anosmia
• Heart problems