Canavan disease

 

Alternative Names

Spongy degeneration of the brain; Aspartoacylase deficiency

Definition

Canavan disease is an inherited condition that affects the breakdown and use (metabolism) of aspartic acid.

Causes

Canavan disease is passed down (inherited) through families. It is more common among the Ashkenazi Jewish population 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)
  • Feeding problems
  • Increasing head size (macrocephaly)
  • Irritability
  • Poor muscle tone, especially of the neck muscles
  • A lack of head control when baby is pulled from a lying to a sitting position (head lag)
  • Poor visual tracking or blindness
  • Reflux with vomiting
  • Seizures
  • Severe intellectual disability
  • 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 for elevated aspartic acid

Treatment

Treatment mostly aims to ease the symptoms of the disease. Lithium and other drugs are being investigated.

Support Groups

Additional information and resources are available from:

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
  • Intellectual disability

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 the parents are carriers.

A diagnosis may be made before the baby is born (prenatal diagnosis) by testing the amniotic fluid.

References

Rezvani I and Melvin JJ. Defects in metabolism of amino acids. In: Kliegman RM, Stanton BF, St. Geme III JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 79.

Review Date: 10/29/2013
Reviewed By: Chad Haldeman-Englert, MD, FACMG, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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