Septo-Optic Dysplasia(De Morsier Syndrome)

Ultrasound

Absent cavum septum pellucidum

Hypoplastic optic nerves (visual impairment and dysfunction of the pituitary- hypothalamic axis).

Box-like frontal horns squared off dorsally and pointing inferiorly at the caudothalamic groove

Bulbous dilatation of the anterior recess of the third ventricle

Dilatation of frontal and occipital horns of lateral ventricles (temporal horns are not dilated as in hydrocephalus)

Normal falx and interhemispheric fissure

Thin corpus callosum

Less frequent features:

    • Dilatation of chiasmatic and suprasellar cistern.
    • Thin corpus callosum.
    • Mental retardation.
    • Hemiparesis.
    • Hypotelorism.
    • Clefting.

 

 

Associated with:

    • Schizencephaly (50%).
    • Hypothalamic hypopituitarism (66%).
    • Diabetes insipidus (50%).

 

Differential diagnosis:

·         Isolated absence of the septum pellucidum – frontal horns usually less squared and no additional anomalies are demonstrated.

·         Lobar holoprosencephaly – features may be identical. Definitive diagnosis may only be made after birth by demonstrating optic nerve hypoplasia.

 

Video clip of absent cavum septum pellucidum