What is Dandy-Walker Syndrome?
Dandy-Walker Syndrome (also sometimes referred to as Dandy-Walker malformation or Dandy-Walker complex) is a congenital disorder caused by malformation of specific parts of the brain. The malformation is typically present at birth, and the condition’s symptoms usually first appear in infancy. However, in a significant number of cases (between 10% and 20%), symptoms don’t appear until later and may not emerge until adulthood.
The parts of the brain affected are those that control movement and coordination. The condition usually causes problems with motor development. Intellectual impairment is also a common symptom, and complications in other parts of the body may also occur.
Features of Dandy-Walker Syndrome
Dandy-Walker Syndrome is caused by abnormalities in and around the cerebellum, a region in the lower rear part of the brain regulating movement. The condition is associated with several specific malformations, including:
- Underdevelopment of the vermis – the central part of the cerebellum. The vermis may be smaller than usual, completely missing, or in the wrong place.
- Underdevelopment of the cerebellum as a whole
- Enlarged fourth ventricle, a cavity between the cerebellum and the brain stem
- Enlarged posterior fossa, the section of the skull that surrounds the cerebellum
In some cases, malformations of other parts of the brain develop. In these relatively rare cases, symptoms are often more severe. Less common malformations include:
- Underdeveloped or missing corpus callosum, a structure that connects the left and right halves of the brain
- Occipital encephalocele, a protrusion of part of the brain through an opening in the back of the skull
- Abnormal location of nerve cells during brain development
Symptoms of Dandy-Walker Syndrome
Dandy-Walker Syndrome affects movement and coordination, but symptoms in other developmental areas and other parts of the body are also common. Symptoms may include:
- Delays in motor development, including sitting, crawling, and walking
- Problems with balance and coordination
- Muscle stiffness
- Paralysis of the legs
- Abnormal eye movements
- Delays in cognitive and intellectual development
- Intellectual impairment and learning disabilities
- Accumulation of fluid in the brain (hydrocephalus). Hydrocephalus can cause symptoms including enlarged head size, vomiting, irritability, and lethargy. Complications of hydrocephalus are the most common cause of death in Dandy-Walker patients.
Less common symptoms of the disorder include:
- Hearing and vision impairment
- Heart defects
- Malformation of the urinary tract
- Extra fingers or toes, or fingers or toes that are fused together
Late-onset Dandy-Walker Syndrome typically has a different set of symptoms than those of the infantile form of the condition. Common late-onset symptoms include:
- Facial paralysis
- Unusual walking gait
- Muscle stiffness
- Muscle spasms
- Behavioral or mood changes
What Causes Dandy-Walker Syndrome?
Scientists don’t know what causes Dandy-Walker malformations in many cases. Research has identified some risk factors that appear to increase the chance of the malformations developing, but no definite cause has been pinpointed.
Risk factors include:
- Genetics. Specific gene mutations have been associated with some cases of the disorder. However, these mutations are only present in a relatively small percentage of cases.
- Environmental factors. Exposure of the mother to conditions and substances known to cause birth defects may play a role in the condition’s development.
- Diabetes. Mothers with diabetes have a higher risk of having a baby with Dandy-Walker malformation.
- Viral infections. Mothers who contract certain infections, such as rubella, during pregnancy are at a higher risk of having a baby with Dandy-Walker malformation.
Is Dandy-Walker Syndrome Hereditary?
Most of the time, Dandy-Walker Syndrome is not inherited by a child from their parents. Only in rare cases is the disorder associated with specific genetic mutations. In those cases, the mutations usually appear to have happened spontaneously during fetal development. The cause of most cases seems to be a combination of genetic and environmental factors.
Dandy-Walker malformation is sometimes associated with other inherited genetic conditions. In these cases, the disorder is inherited through the inheritance pattern of the associated condition.
How Is Dandy-Walker Syndrome Detected?
In some cases, doctors can detect Dandy-Walker malformations before birth using high-resolution imaging scans. However, these scans are not routinely performed during pregnancy, and the condition may escape diagnosis until after the baby is born.
Visible symptoms of the condition, such as developmental delays or the enlarged head characteristic of hydrocephalus, often occur before the baby is a year old. The presence of symptoms that could indicate Dandy-Walker Syndrome may lead a doctor to conduct additional diagnostic testing.
Early signs of the disorder typically include:
- Delays in motor milestones such as sitting, crawling, and walking
- Problems with coordination and balance
- Language delays
- Weak muscle tone
How Is Dandy-Walker Syndrome Diagnosed?
If a doctor suspects that a baby or child may have Dandy-Walker Syndrome, they will pursue further testing to confirm the diagnosis. The diagnostic process may include:
- Imaging scans. Imaging tests such as ultrasound, computerized tomographic (CT), and magnetic resonance imaging (MRI) can identify the brain malformations characteristic of Dandy-Walker Syndrome.
- Genetic testing. A doctor may take this step if there is reason to suspect that an underlying genetic condition may be present along with the Dandy-Walker malformation.
PLEASE CONSULT A PHYSICIAN FOR MORE INFORMATION.
How Is Dandy-Walker Syndrome Treated?
Treatment for Dandy-Walker Syndrome often involves surgical procedures to relieve pressure on the brain caused by hydrocephalus. Other treatments focus on relieving secondary symptoms. Ongoing therapies can lessen the impact of physical and developmental complications. Common treatment options include:
- Surgery to install a shunt used to drain excess fluid from the brain
- Anti-seizure medications
- Physical therapy to improve muscle tone and coordination
- Occupational therapy to help the child learn how to manage everyday activities
- Educational support for intellectual disabilities
How Does Dandy-Walker Syndrome Progress?
The long-term complications of Dandy-Walker Syndrome typically vary in severity depending on the type of malformation. A very small number of patients suffer no significant health complications at all. Intellectual and physical impairments are sometimes mild, but children with minor cognitive impairment may have learning disabilities.
Complications of hydrocephalus and the surgeries used to treat it are the most common life-threatening consequences of the condition.
How Is Dandy-Walker Syndrome Prevented?
Because scientists don’t know precisely what causes Dandy-Walker Syndrome, there is no sure way to prevent it. Avoiding risk factors associated with the condition may help, but research on the effectiveness of such preventive steps is limited. Still, women who are pregnant or could become pregnant should be aware of potential risk factors.
- Diabetic women should follow their doctor’s advice in treating the disease.
- Women should be up-to-date on rubella and other vaccinations before they become pregnant.
- Pregnant women should avoid environmental conditions and substances known to cause birth defects.
Dandy-Walker Syndrome Caregiver Tips
- Stay up-to-date on information about the condition. The current knowledge about Dandy-Walker Syndrome, and its associated effects, is rapidly changing. You’ll be able to best support your child if you know the current state of the research.
- Be prepared to advocate for your child over the long term. Children with Dandy-Walker Syndrome face challenges throughout their lives. You must be ready to act on your child’s behalf to get the educational resources and other resources they need.
- Find a community. Online resources can direct you to support groups and other people who understand the disorder’s challenges.
Dandy-Walker Syndrome Brain Science
Research is ongoing into the cause of Dandy-Walker Syndrome and the most effective methods for treating its complications. The condition appears to be caused by problems in a baby’s genetic material that affect the development of specific brain cells. In particular, scientists are interested in the possibility that specialized nerve cells may not develop properly or move to the correct location in the brain after they develop.
Dandy-Walker Syndrome Research
Title: Study of Choroid Plexus Cauterization in Patients With Hydrocephalus
Principal investigator: Ronald Benveniste, MD, PhD
University of Miami
The purpose of this study is to determine whether endoscopic choroid plexus coagulation is safe in adult patients with communicating hydrocephalus and risk factors for complications from the standard surgical treatment. It may also help determine whether the endoscopic choroid plexus coagulation is effective in treating your communicating hydrocephalus. The Investigators hope that this research will allow them to place fewer shunts in patients with conditions similar to yours, avoiding complications.
Title: Diagnostic Accuracy of ShuntCheck
Principal Investigator: Naomi Abel, MD
University of South Florida
The purpose of this study is to assess the diagnostic accuracy of ShuntCheck compared with radionuclide shunt patency testing (SPS) to detect CSF shunt flow of NPH patients with suspected shunt obstruction.
Title: HCRN Endoscopic Versus Shunt Treatment of Hydrocephalus in Infants (ESTHI)
Principal Investigator: Curtis Rozzelle, MD
Children’s of Alabama
The ESTHI Trial is a multi-center randomized controlled trial (RCT) comparing endoscopic third ventriculostomy with choroid plexus cauterization (ETV+CPC) and shunt in infants with hydrocephalus. The study will leverage the Hydrocephalus Clinical Research Network (HCRN) infrastructure, a committed group of 14 leading North American pediatric neurosurgical centers with a long track record of successful collaborative clinical research and RCTs in hydrocephalus. Optimal cognitive outcome is the primary concern of families and will, therefore, be the primary outcome. Assessment of dMRI, a validated, non-invasive method of measuring white matter microstructural integrity and structural connectivity in the developing brain, will provide further insight into the developmental consequences of these two treatments. The results of the RCT will help families determine the optimal treatment of hydrocephalus for their child.