Dandy Walker Syndrome Life Expectancy
Dandy-Walker syndrome (Dandy-Walker malformation) is a rare difference in how the back of the brain forms before birth: the middle part of the cerebellum (the vermis) is small or missing, and a fluid space called the fourth ventricle is enlarged into a cyst. It affects roughly 1 in 25,000 to 35,000 babies.
Life expectancy varies enormously, from near-normal to death in infancy. What matters most is whether the person develops hydrocephalus and how well it is treated, and whether there are other brain or body differences.
Key facts
- Hydrocephalus (fluid building up in the brain) develops in most people with Dandy-Walker, usually within the first few months of life. Untreated, it is very serious; treatment greatly improves survival.
- Problems linked to hydrocephalus or its treatment, such as a blocked or infected shunt, are the most common cause of death.
- Other malformations, such as heart defects, kidney problems or a chromosome condition, are linked to a poorer outlook, especially when two or more body systems are affected.
- Fewer than half of people with Dandy-Walker have an intellectual disability. Many with milder forms live into adulthood.
Causes
In most people the cause isn't known. Dandy-Walker can occur with some chromosome and genetic conditions, and factors during pregnancy have been suggested, but most cases aren't directly inherited.
Diagnosis
It's often found on a pregnancy ultrasound from about 18 to 20 weeks, or after birth with ultrasound, CT or MRI, usually because a baby's head is growing too fast or development is delayed. In about 10 to 20% of people, symptoms first appear in later childhood or adulthood, and occasionally it's found by chance in someone with no symptoms.
Treatment
- A shunt (a thin tube that drains fluid from the brain to the abdomen) or sometimes an endoscopic procedure is used to treat hydrocephalus.
- Therapies such as physiotherapy, occupational therapy and speech and language therapy help with delays in movement, coordination and communication.
- Seizures, which affect around 15 to 30% of people, are treated with medicines.
Outlook by severity
| Situation | Typical outlook |
|---|---|
| Mild vermis changes, no other brain malformations, hydrocephalus treated or absent | Often survival into adulthood; some people have near-normal development |
| More extensive brain malformations | Higher risk of intellectual and physical disability |
| Malformations in two or more body systems, or a chromosome condition | Highest risk of death in infancy or childhood |
People with shunts need lifelong follow-up. Get urgent help for headache, vomiting, drowsiness, a bulging soft spot in a baby, or any sudden change, which can be signs that a shunt has blocked.
This page is for general information. A child's neurosurgeon and medical team can give a more personal outlook.
References
- Dandy-Walker Malformation. StatPearls, NCBI Bookshelf (NIH). Accessed 1 November 2026.
- Dandy-Walker syndrome. Genetic and Rare Diseases Information Center (NIH). Accessed 1 November 2026.
- Dandy-Walker Syndrome. Cleveland Clinic. Accessed 1 November 2026.
- Dandy Walker Malformation. National Organization for Rare Disorders (NORD). Accessed 1 November 2026.