What is Canavan disease?
Canavan disease is a rare genetic disorder that affects your brain. It’s a neurodegenerative condition, meaning your brain abnormality worsens over time. Lack of an important brain chemical makes your brain become spongy, and it doesn’t function correctly.
Canavan disease is part of a group of diseases called leukodystrophies. They’re rare, genetic, disorders that affect your brain, spinal cord and nerves, and symptoms worsen over time.
What are the different types of Canavan disease?
Canavan disease can occur during infancy or early childhood.
Infantile Canavan disease is the most common type, and it’s more severe. Infants with Canavan disease often die in childhood or adolescence.
Juvenile Canavan disease is less common and milder. This type doesn’t appear to shorten a person’s life.
Who is at risk for Canavan disease?
Canavan disease can affect anyone. But it more often happens in Ashkenazi Jews with ancestors from eastern Poland, Lithuania and Western Russia. In this population, it affects 1 of every 6,400 to 13,500 babies.
Symptoms and Causes
What causes Canavan syndrome?
Canavan disease is inherited, which means it’s passed down from parents to children.
A mutation in a gene that makes an enzyme called aspartoacylase (ASPA) causes the disease. ASPA’s job is to break down a brain chemical called N-acetyl-aspartate (NAA).
People with Canavan disease don’t have enough ASPA, so NAA builds up in brain tissue. This damages their myelin (white matter), a fatty substance that protects and nourishes nerves in their brain and spine. Over time, this causes their brain to deteriorate into spongy tissue with lots of tiny fluid-filled spaces. It also prevents their brain from sending and receiving nerve signals properly.
What are the symptoms of Canavan disease?
Signs of infantile Canavan disease usually begin appearing at 3 to 6 months of age. They include:
- Abnormal muscle tone, such as weak or stiff muscles.
- Abnormally large head (macrocephaly) that’s hard to control.
- Developmental delays, such as not being able to roll, sit, crawl, walk or talk.
- Difficulty eating or swallowing.
- Lack of motor skills to control muscle movement, sometimes described as “floppiness.”
- Quiet or unresponsive behavior, showing little interest or emotion.
Most children get worse quickly and develop life-threatening problems by 10 years old.
- Hearing loss.
- Intellectual disability.
- Muscle spasms.
- Trouble swallowing.
- Vision loss.
People with the juvenile form of Canavan disease may experience only mild developmental delays. They might have problems speaking or keeping up at school. But the symptoms aren’t as severe.
Diagnosis and Tests
How is Canavan disease diagnosed?
If your healthcare provider suspects Canavan disease, you may have several tests to diagnose it:
- Blood or urine tests that test for levels of NAA or ASPA or tests that look for the genetic mutation.
- Lab tests of specific skin cells (called cultured fibroblasts) to look for a lack of ASPA.
Canavan disease may be diagnosed before your baby is born. Amniocentesis is a test that uses a sample of the fluid that surrounds your fetus to measure levels of NAA. It’s usually performed when a birthing parent is 15 to 20 weeks pregnant.
Another test is available for parents with a high risk of Canavan disease or a known genetic mutation. Chorionic villus sampling (CVS) uses a tissue sample from your placenta to test for the genetic mutation. It’s performed when a birthing parent is 10 to 12 weeks pregnant.
Management and Treatment
How is Canavan disease treated?
There isn’t a cure for Canavan disease. Treatment aims to manage symptoms and keep the person comfortable as long as possible. Options may include:
- Feeding tubes to deliver nutrition and fluids.
- Medications to control seizures (anticonvulsants).
- Physical therapy to improve posture and communication.
Genetic testing and genetic counseling can help the entire family understand the risk of Canavan disease in future children.
How can I prevent Canavan disease?
You can’t prevent Canavan disease, but families can have DNA tests to see if they carry the genetic mutation. Both parents have to have the mutation in order for their baby to get the disease. Testing can help them make informed decisions about having children.
Outlook / Prognosis
What is the outlook for people with Canavan syndrome?
The outlook for people with Canavan disease depends on the type of disease: infantile or juvenile. Children with infantile Canavan disease usually survive until about 10 years old. Some may survive into their teens or 20s. But in mild juvenile Canavan disease, life expectancy is usually normal.
Scientists have identified the gene that causes Canavan disease and are testing possible treatments. Strategies include:
- Gene therapy.
- Man-made ASPA that can be injected into the bloodstream.
- Stem cell therapy.
What can I ask my child’s healthcare provider about Canavan disease?
Consider asking your child’s healthcare provider:
- What disabilities can I expect to see and when?
- What’s my child’s life expectancy?
- How can I make my child more comfortable and safer?
- What specialists does my child need to see?
- How often should we see them?
- Should our family get genetic testing?
How can I cope with my child having Canavan disease?
To cope with Canavan disease, consider:
- Counseling (talk therapy).
- Getting involved with organizations that support patients and research.
- Support groups.
A note from Cleveland Clinic
Canavan disease is a rare genetic disorder that can make your brain’s white matter break down. Talk to your healthcare provider about the care your child will need and whether your family members should have DNA testing. Although the disease is often severe and life-threatening, scientists are working on possible treatments.
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