What is the definition of Canavan Disease?
Canavan disease is a progressive, fatal, genetic disorder affecting the central nervous system, muscles, and eyes. Early symptoms in infancy may include increased head size, weakness, low muscle tone and loss of head control. Symptoms progress to seizures, blindness, inability to move voluntarily and difficulty eating solids or swallowing liquids. This condition is caused by changes in the ASPA gene and is inherited in an autosomal recessive pattern. Canavan disease is diagnosed based on symptoms, laboratory testing, and genetic testing. There is no specific treatment. Treatment is focused on managing symptoms.
What are the alternative names for Canavan Disease?
- Canavan-van Bogaert-Bertrand disease
- Spongy degeneration of the central nervous system
- Von Bogaert-Bertrand disease
- Aspartoacylase deficiency
- ASPA deficiency
- ASP deficiency
- ACY2 deficiency
- Aminoacylase 2 deficiency
What are the causes for Canavan Disease?
Canavan disease is caused by genetic alterations in the ASPA gene.
What are the symptoms for Canavan Disease?
The following list includes the most common signs and symptoms in people with Canavan disease (CD). These features may be different from person to person. Some people may have more symptoms than others and symptoms can range from mild to severe. This list also does not include every symptom or feature that has been described in Canavan disease.
- Damage to the optic nerve (Optic atrophy)
- Deafness (Hearing loss)
- Increased head size (macrocephaly)
- Intellectual disability and developmental delay
- Low muscle tone (hypotonia)
- Gastroesophageal reflux
- Feeding difficulties in infancy
- Inability to straighten joints (Flexion contractures)
- Difficulty holding up head when pulled into a seated position (Head lag)
- Abnormal growth of white matter in the brain (leukodystrophy)
- Sleep disturbances
Infants with Canavan disease appear normal at birth and usually develop symptoms between two and six months of age. These include low muscle tone, poor head control, an increased head size, and poor motor development. Later symptoms include optic nerve damage, blindness, and seizures. Over time, stiffening of arms and legs combined with low muscle tone, lead to an inability to move and swallow voluntarily.
What are the current treatments for Canavan Disease?
There is no specific treatment for Canavan disease. Treatment is aimed at preventing and/or managing the known symptoms and complications associated with this condition. This may include seizure medication, physical and other therapies, and maintenance of food and water intake.
Specialists who might be involved the care of someone with Canavan disease include:
- Ophthalmologist (eye doctor)
- Genetics specialist (genetic counselor and/or geneticist)
- Physical therapist
Is Canavan Disease an inherited disorder?
Canavan disease is inherited in an autosomal recessive pattern. All individuals inherit two copies of each gene. Autosomal means the gene is found on one of the numbered chromosomes found in both sexes. Recessive means that both copies of the responsible gene must be altered to have the condition.
People with autosomal recessive conditions inherit one alteration from each of their parents. The parents, who each have one gene alteration, are known as carriers. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When two carriers of an autosomal recessive condition have children, there is a 25% (1 in 4) chance to have a child with the condition.