Here is what we know so far:

Septo-Optic Dysplasia/
De Morsier’s Syndrome

Introduction

Septo-Optic Dysplasia (SOD), also known as de Morsier’s syndrome, is a rare disorder characterized by visual impairment, pituitary deficiencies, and specific brain abnormalities (absence of the septum pellucidum and corpus callosum). SOD may be apparent in early infancy, during childhood, or, in some cases, as late as adolescence. In some cases, individuals with SOD will have brain abnormalities that affect just the structure of the brain, while others will have abnormalities that affect the function of the brain. Typically, however, a child will have both types, resulting in problems ranging from mild to very severe.

The cause of SOD is unknown, however, there is evidence for both genetic and acquired cases. While there have been reports of SOD occurring in two children from the same family, it is typically not the case. Most cases are sporadic (or random) in nature. In fact, some researchers believe that SOD is the result of a lack of blood supply or oxygen to the front part of the brain during a critical stage of fetal development.

Features and Characteristics

The following features have been identified in some children with SOD. Not all of these characteristics will be present in every child:

• Optic nerve hypoplasia (underdevelopment of optic nerves), resulting in mild to severe vision impairment
• Nystagmus (involuntary movement of the eyes)
• Pupil dilation in response to light
• Inward and outward deviation of the eyes
• Absent septum pellucidum
• Absent corpus callosum
• Hypopituitarism (diminished activity of the pituitary gland), resulting in various hormonal problems
• Hypotonia (low tone)
• Seizures
• Intellectual impairment (varies in severity from learning disabilities to mental retardation)
• Psychomotor retardation (delays in skills that require the coordination of mental and muscular activity)
• Jaundice at birth
• Sensory integration dysfunction

Pituitary Deficiencies

The pituitary gland is found at the base of the brain. It plays an important role in that it makes hormones and directs other glands in the body to make hormones. These hormones are required for growth, energy control (metabolism), and sexual development. Individuals with SOD often have problems with their pituitary gland and as a result, have difficulty making these much needed hormones (known as hypopituitarism).

The following hormones may be affected when there is a problem with the pituitary gland:

Growth hormone - When there is a lack of growth hormones, a child will grow slower than normal. Without treatment, a child will be shorter than expected when growth is complete.

ACTH - This hormone, made in the pituitary gland, signals the adrenal gland to make cortisol, which is needed to help the body create energy, control blood sugar, and allow for proper heart and lung function.

Thyroid hormone - This hormone is made by the thyroid gland in the neck. With a poorly functioning pituitary gland, the thyroid gland does not get the proper signal to make this hormone. A lack of thyroid hormone can result in poor growth, slowing of mental and muscle function, weight gain, irregular menstrual cycle, hair loss, hoarse voice, brittle nails, and coarse skin.

Anti-diuretic hormone (ADH) - This hormone is produced by the pituitary gland and is responsible for keeping water in the body by controlling the amount of urine that is created. Without enough ADH, a person cannot control the amount of urine and may lose too much water from the body, resulting in dehydration. Dehydration can lead to serious problems. When a child does not make enough ADH, he or she is referred to as having diabetes insipidus.

Sex hormones - The pituitary gland produces two hormones that are involved in sexual development. During teenage years, these hormones are responsible for sexual maturation (puberty). They also control a woman’s menstrual cycle. Without these hormones, a child’s sexual development is delayed, a girl’s menstrual cycle is irregular, and pregnancy becomes difficult.

Hormone replacement therapy is available for all of the above deficiencies, either by mouth or injection.

Vision Impairment

Optic nerve hypoplasia (ONH) is a condition where the optic nerves are small and underdeveloped. The typical person has over 1 million nerve fibers from each eye to the brain. Individuals with ONH, however, have far fewer connections. The fewer connections between the eye and the brain, the worse the vision. The severity of the visual impairment for individuals with ONH can range from near normal vision to complete blindness.

In addition to ONH, some children with SOD have nystagmus, which are unusual eye movements. The eyes seem to move around with no real pattern or purpose. This occurs because the eyes are not able to focus well enough to hold still.

Diagnosis

A diagnosis of SOD can be made based on specific findings. A child suspected of having SOD should see a team of specialists to confirm the diagnosis. An ophthalmologist can diagnose ONH by looking into the eyes with an ophthalmoscope. A neurologist will determine, either by MRI or CT-scan, whether the septum pellucidum (and in some cases, the corpus callosum) is absent. And, an endocrinologist can determine whether there are pituitary deficiencies that will result in hormonal problems. If there are positive findings in these three areas, the child may then qualify for an SOD diagnosis.

Treatment

There is no cure for SOD, therefore, treatment is symptomatic. As mentioned earlier, hormone deficiencies can be treated with hormone replacement therapy. Vision therapy and services will likely be required, and physical and occupational therapies may be helpful for mobility training. What’s important to note is that if SOD is diagnosed early and the hormone deficiencies are identified, many of the symptoms seen in children with SOD may be prevented altogether.

What to Expect

The prognosis for individuals with SOD varies according to the type and severity of symptoms. While a neurologist can determine at an early age if there are brain abnormalities, he or she cannot determine whether the child will have problems with brain function. In children less than 3-4 years of age, it is often difficult to predict future brain function such as speech, intelligence, or learning.