Septo-optic dysplasia complex: Clinical and radiological manifestations in Omani children

Abstract

Background: Septo-optic dysplasia (SOD), also known as de-Morsier's syndrome, is a rare disorder characterized by any combination of optic nerve hypoplasia (ONH), pituitary gland hypoplasia, and midline abnormalities of the brain including absence of septum pellucidum and corpus callosum dysgenesis. It is typically diagnosed in infancy and has a variable presentation that includes visual, neurologic, and/or hypothalamic-pituitary endocrine deficits.

Purpose: To demonstrate the ophthalmic, endocrine, and neurologic spectrum of SOD in five Omani children and address the crucial role of high-resolution neuroimaging for its early and accurate diagnosis.

Materials and methods: A retrospective chart review was performed in 2010 of all children in the pediatric ophthalmology database of Sultan Qaboos University Hospital (SQUH) who were diagnosed to have ONH. All relevantdemographic, ophthalmic, neurologic, endocrine, and neuro-radiological manifestations were recorded in a data collection form. All previous neuroimaging results were reviewed by a neuro-radiologist.

Results: Five patients (four males, one female) with the diagnosis of ONH were included in the study. They presented during the period 1998-2008. All patients were born at term, with normal birth weights to healthy mothers with insignificant antenatal history. Age at presentation ranged from three months to one year. Manifestations at presentation included severe visual impairment (5/5), neonatal hypoglycemia (3/5), seizure disorder (2/5), and failure to thrive (4/5). ONH was bilateral in 3/5 patients and unilateral in (2/5). Brain and orbit imaging revealed varying anomalies in all patients. These included absent septum pellucidum (3/5), severe corpus callosum agenesis (1/5), ectopic pituitary (5/5), falx cerebri deficiency (1/5), optic nerve hypoplasia (5/5), optic chiasmal hypoplasia (5/5), and olfactory tract hypoplasia (1/5). Endocrine deficits were detected in 4/5 patients (3 with panhypopituitarism, and 1 with growth hormone deficiency) and necessitated replacement therapy.

Conclusion: SOD is a clinically heterogeneous disorder with a wide spectrum of ophthalmic, endocrine, and neurologic manifestations. All features might not be present in a single patient. A high consanguinity rate and lack of history of alcohol and drug use were observed in our cohort. Most affected children present first to the pediatrician with failure to thrive. Radiological confirmation of ONH necessitates high-resolution imaging and interpretation by an experienced neuro-radiologist. In our cohort, all patients with ONH had associated optic chiasmal hypoplasia. Early detection and treatment reduces disease-related morbidity, and can be life saving.

Keywords: De-Morsier's syndrome; Septo-optic dysplasia; hypopituitarism; midline brain defects; optic nerve hypoplasia.

Figure 1

Fundus photo (RetCam ®) of left eye of patient 1 shows small pale disc with double ring sign. The fovea is also hypoplastic and the retinal vessels are tortuous. This patient had bilateral optic nerve hypoplasia, and vision was at the light perception level in both eyes

Figure 2

Fundus photo of right eye of patient 5shows a pale disc with the double ring sign. The disc is vertically oval and has a greyish tinge. The vessels are tortuous and have an anomalous branching pattern

Figure 3

Coronal T1W MR image at suprasellar region of patient 2, shows hypoplasia of left optic nerve and hemiatrophy optic chiasm (arrow)

Figure 4

Coronal T2W MR image at 3^rd ventricle level of patient 3, shows absent septum pellucidum (arrow head)

Figure 5

Sagittal T1W MR image at midline of patient 5, shows ectopic posterior pituitary and hypoplastic pituitary stalk (arrow head)

Figure 6

Coronal T2W MR image at frontal lobes level of patient 2 shows absent olfactory bulb (arrow head)