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Living with Hydranencephaly

A rare brain condition in which the main parts of the brain are missing and replaced by fluid-filled sacs.

Understanding Hydranencephaly

Hydranencephaly is a rare condition in which the brain's cerebral hemispheres are missing and replaced by sacs of cerebrospinal fluid (CSF).

Infants may look and act typical at birth, but irritability and increased muscle tone (hypertonia) often develop within a few weeks. Other signs may include seizures, hydrocephalus (extra fluid in the brain), vision problems, deafness, paralysis, lack of growth, and intellectual disability. It may be seen during pregnancy or in newborns.

Signs & symptoms

Symptoms vary from person to person. GARD lists these among the most common:

  • Global developmental delay
  • Blindness
  • Infant hearing loss
  • Lethargy
  • Slow growth after birth
  • Arching of the back (opisthotonus)

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

    Specialists who may be involved include brain and nervous system specialists and genetic specialists.

  3. Consider genetic testing

    Changes in NDE1 are linked to this condition. Genetic testing and counseling can help confirm a diagnosis and explain what it means for your family.

  4. Connect with expert centers

    Hydrocephalus Association may keep lists of experts for this condition.

Care & treatment

Care team
Brain and nervous system specialists (neurologists); Genetic specialists (geneticists)
Expert care
Expert lists: Hydrocephalus Association
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 Hydrocephalus Association and other patient organizations
  • 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 therapies and supports could help my child?
How are seizures and fluid buildup managed?
Would genetic testing for NDE1 help our family?

Quick facts

Symptoms usually startduring Pregnancy and as a Newborn
InheritanceAutosomal Recessive
GenesNDE1

Changes in the NDE1 gene cause this condition. It is autosomal recessive, so a child inherits a changed copy of the gene from each parent.

GeneticNeurological

Also known as: congenital absence of cerebral hemispheres; hydrancephaly; hydranencephaly (disease)

Patient organizations

Source: NIH GARD · HydranencephalyGARD ID 6681 · 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 Hydranencephaly.

Explore the Hydranencephaly blog

Explore research for Hydranencephaly

Explore actively recruiting Hydranencephaly studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Hydranencephaly 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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