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Living with Absent septum pellucidum

A rare brain difference in which a thin membrane in the middle of the brain is missing.

Understanding Absent septum pellucidum

Absent septum pellucidum is a rare condition in which a thin membrane in the middle of the brain is missing.

When it is missing, symptoms may include learning difficulties, behavior changes, seizures, and vision changes. It is not usually found alone. It is tied to other conditions such as septo-optic dysplasia. Imaging tests can make the diagnosis.

Signs & symptoms

Symptoms vary from person to person. GARD's summary lists these possible signs:

  • Learning difficulties
  • Behavior changes
  • Seizures
  • Vision changes

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Your doctor may refer you to a specialist who knows rare conditions.

  3. Ask which tests can help

    Your care team will decide which exams and tests can confirm the diagnosis.

Care & treatment

Care team
A doctor familiar with rare conditions, plus specialists as needed
Expert care
Ask about multidisciplinary care centers for rare conditions
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with rare disease patient organizations for support
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
Which other conditions, like septo-optic dysplasia, should be checked for?
Which specialists should follow vision, learning, and seizures?
What imaging follow-up is recommended?

Quick facts

GARD doesn't describe a cause for this condition yet. It is usually found with other conditions such as septo-optic dysplasia.

Also known as: absence of septum pellucidum; absence of the septum pellucidum; agenesis of the septum pellucidum; congenital absence of septum pellucidum; missing septum pellucidum

Patient organizations

Rare-disease groups that can help

Source: NIH GARD · Absent septum pellucidumGARD ID 9253 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Absent septum pellucidum.

Explore the Absent septum pellucidum blog

Explore research for Absent septum pellucidum

Explore actively recruiting Absent septum pellucidum studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Absent septum pellucidum with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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