Canavan disease
Definition
Canavan disease is an inherited condition that affects the breakdown and use (metabolism) of aspartic acid.
Alternative Names
Spongy degeneration of the brain; Aspartoacylase deficiencyCauses
Canavan disease is inherited as an autosomal recessive trait. It is more common among Ashkenazi Jews than in the general population.
The lack of the enzyme, aspartoacylase, leads to a buildup of material called N-acetylaspartic acid in the brain. This causes the white matter of the brain to break down (deteriorate).
Symptoms
Symptoms usually begin in the first year of life. Parents tend to notice when a child is not reaching certain developmental milestones, including head control.
Symptoms include:
- Abnormal posture with flexed arms and straight legs
- Backflow of food material into the nose (nasal regurgitation)
- Blindness
- Feeding problems
- Increasing head size (macrocephaly)
- Lack of head control when baby is pulled from lying to sitting position (head lag)
- Poor muscle tone, especially of the neck muscles
- Reflux with vomiting
- Seizures
- Severe mental retardation
- Swallowing difficulties
Exams and Tests
- Exaggerated reflexes (hyperreflexia)
- Joint stiffness
- Loss of tissue in the optic nerve of the eye (optic atrophy)
Tests:
- Blood chemistry
- CSF chemistry
- Genetic testing for aspartoacylase gene mutations
- Head CT scan
- Head MRI scan
- Urine chemistry
Treatment
Treatment aims to ease the symptoms of the disease. There is no specific treatment.
Support Groups
Additional information and resources are available from:
Canavan Foundation
877-4-CANAVAN
Outlook (Prognosis)
With Canavan disease, the central nervous system breaks down. Patients are likely to become disabled.
Death often occurs before 18 months of age. However, some patients live until they are teenagers or, rarely, young adults.
Possible Complications
This is often a fatal disorder. It includes severe disabilities such as:
- Blindness
- Inability to walk
- Mental retardation
When to Contact a Medical Professional
Call your health care provider if your child has any symptoms of Canavan disease.
Prevention
Genetic counseling is recommended for people who want to have children and have a family history of Canavan disease. Counseling should be considered if both parents are of Ashkenazi Jewish descent. For this group, DNA testing can almost always tell if one or both parents is a carrier.
References
Rezvani I. Defects in Metabolism of Amino Acids. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Kliegman: Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 85.
Reviewed By: Chad Haldeman- Englert, MD, Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
