(SOD) is a
Congenital Malformation Syndrome manifested by hypoplasia (underdevelopment) of the
Optic Nerve ,
Hypopituitarism , and absence of the
Septum Pellucidum (a midline part of the
Brain ). In a severe case, this results in
Pituitary Hormone deficiencies,
Blindness , and
Mental Retardation . However, there are milder degrees of each of the three problems, and some children only have one or two of the three.
The optic nerve hypoplasia is generally manifested by
Nystagmus (involuntary eye movements, often side-to-side) and a smaller-than-usual optic disk. The degree of visual impairment is variable, and ranges from normal vision to complete blindness. When nystagmus develops, it typically appears by 1-4 months of age, and usually indicates that there will be a significant degree of visual impairment, but the severity is difficult to predict in infancy. Although there are many measures to compensate for visual impairment, no treatment is available to induce normal optic nerve function.
The degree of
Pituitary deficiency is also variable, and ranges from normal function, to deficiency of a single hormone, to deficiency of both anterior and posterior hormones (termed
Panhypopituitarism ). Hypopituitarism in this syndrome is most often manifested by
Growth Hormone Deficiency . If severe, it can lead to diagnosis in the first days of life by causing
Hypoglycemia ,
Jaundice , and
Micropenis (if a boy). The cause of the jaundice is unknown, and an unusual aspect of it (compared to most
Neonatal Jaundice ) is that it can be largely a conjugated (direct) hyperbilirubinemia suggested of obstructive
Liver disease. It typically resolves over several weeks once hormone replacement is begun. All of the pituitary hormones can be replaced, and this is the treatment for deficiencies. Septo-optic dysplasia is one of the most common forms of congenital growth hormone deficiency.
The brain effects are also variable and range from normal intelligence to severe mental retardation.
Seizure s sometimes occur. Prediction of intellectual outcome in infancy is difficult. Various types of
Early Intervention or equivalent programs can help a child reach full developmental potential, but if brain impairment is significant, it cannot be made normal by any treatment.
The cause of septo-optic dysplasia is not known. Rare familial recurrence has been reported, suggesting at least one
Genetic form, but in most cases it is a sporadic birth defect of unknown cause and does not recur again with subsequent pregnancies.
