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Genetic disease that causes the triad of optic nerve hypoplasia, structural brain abnormalities, and hypothalamic/pituitary deficiencies.

Septo-Optic Dysplasia; Optic Nerve Hypoplasia; Dwarfism-Septo-Optic-Dysplasia.


Some cases are sporadic, whereas other cases seem to indicate autosomal dominant and recessive patterns of inheritance.

Caused by mutation in the homeobox gene HESX1. The typical picture includes optic hypoplasia, pituitary hypofunction, and midline defects of the prosencephalon. Milder forms exist in individuals with heterozygous mutations of the gene.

Clinical picture, family history, brain imaging, and cytogenetic identification of mutations of the HESX1 gene.

Wide variability in the clinical picture. The syndrome is characterized by hypoplasia of the optic disk and nerve, hypothalamic-pituitary axis defects, and agenesis of the septum pellucidum. Agenesis of the corpus callosum, hypoplastic cerebellar changes similar to Dandy-Walker malformation, hemiparesis or hemiplegia, spasticity, and mental retardation (mild-to-severe) have been described as optional signs. The extent of pituitary involvement ranges from growth hormone deficiency only to panhypopituitarism. The clinical picture of decreased hormone levels may result not only in short stature but also in hypoglycemia (decreased levels of adrenocorticotropic hormone), diabetes insipidus, and precocious puberty. Visual impairment is usually noted at birth, ranging from decreased vision in one eye to no vision in both eyes secondary to optic disc atrophy and corneal opacification. Variable pupillary dilatation and searching nystagmus can often be found. Facial features include a flat face and midline cleft lip. Abnormal external genitalia (cryptorchidism, micropenis) have been reported. Patients are prone to intercurrent infections.

The hazards of anesthetizing a patient in whom the syndrome has not been recognized have been documented. Bear the diagnosis in mind in a patient with visual impairment and small stature. Ideally, the patient is under the care of an endocrinologist. Ask about episodes of hypoglycemia. The patient may be on chronic hormone replacement therapy, requiring additional hydrocortisone stress coverage in the perioperative period. Preoperative assessment should include evaluation of hydration and electrolytes in view of possible diabetes insipidus. Check seizure control.

Sudden unexpected death has been described in these patients, probably as a consequence of intercurrent viral illness and consecutive adrenal crisis. Specific attention must be paid to prevent hypoglycemia. Maintaining hydration, if diabetes insipidus is present, is crucial, and extra doses of hydrocortisone to cover for perioperative stress are required. Temperature control is important because patients may suffer from thermoregulatory disturbances.

Be aware of interactions between anticonvulsants and anesthetic drugs. Hormone replacement therapy must be maintained.

Brodsky MC, Conte FA, Taylor D, et al: Sudden death in septo-optic dysplasia: Report of 5 cases. Arch Ophthalmol 115:66, 1997.  [PubMed: 9006427]
Sherlock DA, McNicol LR: Anaesthesia and septo-optic dysplasia. Implications of missed diagnosis in the peri-operative period. Anaesthesia 42:1302, 1987.  [PubMed: 3434762]
Thomas PQ, Dattani MT, Brickman JM, et al: Heterozygous HESX1 mutations associated with ...

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