congenital absence of septum pellucidum

The absence of the septum pellucidum is a rare condition that affects the structure of the brain. Specifically, a thin membrane called the septum pellucidum is missing from its normal position in the middle of the brain. When it is missing, symptoms may include learning difficulties, behavioral changes, seizures, and changes in vision. Absence of the septum pellucidum is not typically seen as an isolated finding. Instead, absence of the septum pellucidum is associated with other conditions such as septo-optic dysplasia. Treatment options for the condition vary depending on the underlying disorder. Diagnosis of absence of the septum pellucidum can be made through imaging such as an MRI. Symptoms of absence of the septum pellucidum typically present during childhood, but a diagnosis can also be made before an individual is born (prenatally). If an individual is found to be missing the septum pellucidum, a search for an underlying disorder should be made.

Definition from the Mondo Disease Ontology (MONDO:0022349), read 2026-09-29. CC BY 4.0.