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Test Code AACYL Aminoacylase-1 Deficiency, 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.


Useful For

Follow-up quantitation of abnormal organic acid elevations of N-acetylated amino acids, in particular N-acetylalanine, N-acetylglycine, N-acetylmethionine, and N-acetylglutamic acid

 

Diagnosis of individuals with aminoacylase-1 deficiency

 

Evaluating patients with neurologic and psychiatric symptoms of unknown etiology

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Reporting Name

Aminoacylase-1 Deficiency, U

Specimen Type

Urine

Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Frozen (preferred) 90 days
  Refrigerated  60 days

Reject Due To

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

Clinical Information

Aminoacylase-1 deficiency (ACY1D) is a very rare autosomal recessive metabolic disorder caused by disease-causing variants in the ACY1 gene and characterized by increased urinary excretion of N-acetylated amino acids, including the derivatives of serine, glutamine, alanine, methionine, glycine, leucine, and valine.(1) The phenotype is variable with less than 20 patients described in the literature. Clinical findings range from asymptomatic to significant neurologic impairments including intellectual disability, seizures, sensorineural hearing loss, and behavioral features such as attention deficit hyperactivity disorder and autism.(2) According to a recent paper, the symptoms described in the literature vary widely, thus making the relationship between clinical symptomatology and ACY1D yet unclear.(3)

 

For patients with a clinical suspicion of ACY1D, the biochemical diagnosis is established via elevated N-acetylated amino acids in urine. For confirmation, molecular genetic testing of the ACY1 gene is available; order CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify Gene List ID: IEMCP-M9821N.

Reference Values

N-acetylglycine: ≤15.00 mmol/mol creatinine

N-acetyl alanine: ≤10.00 mmol/mol creatinine

N-acetylglutamic acid: ≤20.00 mmol/mol creatinine

N-acetylmethionine: ≤5.00 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).

Day(s) Performed

Monday

Report Available

3 to 9 days

Specimen Retention Time

2 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AACYL Aminoacylase-1 Deficiency, U 104695-2

 

Result ID Test Result Name Result LOINC Value
621432 Interpretation 59462-2
621428 N-acetylglycine 104696-0
621429 N-acetylalanine 104697-8
621430 N-acetylglutamic acid 104698-6
621431 N-acetylmethionine 104699-4
621433 Reviewed By 18771-6