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Test Code NAACD N-Acetylaspartic Acid, Canavan Disease, Random, Urine


Necessary Information


1. Patient's age and sex are required.

2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information



Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 10 mL

Pediatric: If insufficient collection volume, submit as much specimen as possible in a single container; the laboratory will determine if volume is sufficient for testing.

Collection Instructions:

1. Collect a random urine specimen (first morning void preferred).

2. No preservative.


Secondary ID

621423

Useful For

Diagnosis and monitoring of individuals with Canavan disease

 

Follow-up quantitation of abnormal organic acid elevations of N-acetylaspartic acid

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Reporting Name

N-acetylaspartic acid, U

Specimen Type

Urine

Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 90 days
  Refrigerated  90 days
  Ambient  14 days

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Canavan disease is a leukodystrophy disorder characterized by delayed development beginning at age 3 to 6 months followed by regression, head lag, macrocephaly, and hypotonia. Although the phenotypic spectrum ranges in severity, death usually occurs within the first two decades of life. Affected patients receive symptomatic care and supportive management. While there is currently no treatment available for Canavan disease, clinical trials may be available.

 

The incidence of Canavan disease unknown, although there is a higher incidence in the Ashkenazi Jewish population. Canavan disease is inherited in an autosomal recessive manner and is caused by disease-causing variants in the ASPA gene. This leads to a deficiency of the enzyme aspartoacylase and increased urinary excretion of N-acetylaspartic acid (NAA). For patients with a clinical suspicion of Canavan disease, the biochemical diagnosis is established via elevated NAA in urine. Molecular genetic testing of the ASPA gene  is available for confirmation and testing of at-risk family members to provide assessment for recurrence risks; order CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify Gene List ID: IEMCP-TF8VHL.

Reference Values

≤50.00 mmol/mol creatinine

Interpretation

When abnormal results are detected, a detailed interpretation is given including an overview of the results and of their significance; a correlation to available clinical information; elements of differential diagnosis; recommendations for additional biochemical testing and in vitro confirmatory studies (enzyme assay, molecular analysis).

CPT Code Information

83921

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NAACD N-acetylaspartic acid, U 76023-1

 

Result ID Test Result Name Result LOINC Value
621425 Interpretation 59462-2
621424 N-acetylaspartic acid 76023-1
621426 Reviewed By 18771-6