What is Canavan Disease?

Canavan disease is a rare genetic disorder that affects the nervous system. It is a type of leukodystrophy, a group of conditions that affect the white matter of the brain. These conditions damage the myelin sheath — the protective coating around nerve cells in the brain and spinal cord. Myelin helps messages travel quickly between cells in the brain and body.

Causes of Canavan disease

People with Canavan disease are born with a change in the ASPA gene. This gene makes a helpful protein that breaks down N-acetyl-L-aspartic acid (NAA). In people with Canavan disease, the protein doesn’t work the way it should, causing NAA to build up in the brain. This buildup affects how the myelin sheath forms. Without healthy myelin, messages from the brain travel slowly or stop altogether, leading to serious nerve problems.

Signs and symptoms of Canavan disease

There are different forms of Canavan disease, including typical and atypical forms.

The typical form of Canavan disease usually starts in infancy. Symptoms can include:

• Low muscle tone
• A large head (called macrocephaly)
• Problems with vision and movement
• Problems with feeding
• Seizures
• Delays in reaching milestones (like sitting or walking)
• Losing skills that were already learned (called developmental regression)

The atypical form of Canavan disease can begin anytime between infancy and the teenage years. Symptoms may include:

• Developmental delays with or without loss of skills (developmental regression)
• A large head (called macrocephaly) or typical head size
• Vision problems
• Difficulties with coordination

Testing and diagnosis

In addition to looking at physical symptoms, diagnosing Canavan disease involves several tests: 

• A brain MRI (magnetic resonance imaging) with magnetic resonance spectroscopy – which looks at chemicals inside the brain – can show patterns in brain tissue that are typical of Canavan disease.
• Urine tests, called biochemical testing, check for high levels of NAA in the body.
• Genetic testing looks for changes in the gene linked to Canavan disease. This test is done from a blood or saliva sample or a cheek swab. 

Together, results from these tests give a clear picture and help confirm the diagnosis.

Treatment for Canavan disease

There is currently no cure for Canavan disease, but there are treatments to help manage symptoms and keep children comfortable. Each child’s treatment is unique depending on their symptoms.

Children with Canavan disease should be monitored for:

• Feeding, growth and weight changes
• Bone issues, such as scoliosis, dislocated joints and low bone density, which are linked to motor issues in Canavan disease

If any of these conditions are found, pediatric subspecialists can help treat them. Many children with Canavan disease also benefit from physical, occupational and speech therapy to combat challenges caused by the disease.

Clinical trials may also be an option. Your doctor can help you learn more about these studies. You can also find a list of ongoing studies at www.clinicaltrials.gov.

Follow-up

Children with Canavan disease need regular monitoring by neurologists, as well as ongoing therapy and coordinated care by other medical subspecialists as needed. At Children’s Hospital of Philadelphia (CHOP), families have access to advanced, multidisciplinary care, delivered by clinicians with deep expertise in leukodystrophies, all within a compassionate, family-centered environment.

Long-term outlook for children with Canavan disease

Canavan disease is a progressive, life-limiting disease, with symptoms that worsen over time. However, there are treatments that can improve a child’s quality of life. CHOP is one of the premiere institutions for leukodystrophy care and a designated Center of Excellence. Our ongoing research efforts aim to enhance outcomes for children with Canavan disease and offer families hope for the future of leukodystrophy care.