Prevalence:

• 1 in 10,000 births.

Ultrasound diagnosis:

• Absent cavum septum pellucidum with communicating frontal horns.

Associated abnormalities:

• The incidence of chromosomal abnormalities and genetic syndromes is not increased.
• In septo-optic dysplasia, in addition to absent cavum septum pellucidum, there is hypoplasia of the optic nerves  and / or hypothalamic-pituitary abnormalities.

Investigations:

• Detailed ultrasound examination, including neurosonography.
• Fetal brain MRI to assess optic nerves and chiasm, hypothalamic-pituitary gland, and to demonstrate possible associated cortical abnormalities (polymicrogyria and schizencephaly).

Follow up:

• Follow-up should be standard.

Delivery:

• Standard obstetric care and delivery.

Prognosis:

• Isolated absent cavum septum pellucidum: usually asymptomatic.
• Septo-optic dysplasia: visual disturbances may range from blindness to almost normal vision. Hormone insufficiencies can be treated with hormone replacement therapy.

Recurrence:

• No increased risk of recurrence.