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
This test provides a quantitative analysis of N-acetyl alanine, N-acetylglycine, N-acetylmethionine, and N-acetylglutamic acid for the diagnosis of aminoacylase-1 deficiency.
Gas Chromatography Mass Spectrometry (GC-MS)
ACY1
ACY1D
N-acetylated amino acids
N-acetyl amino acids
N-acetyl alanine
N-acetyl glycine
N-acetyl methionine
N-acetyl glutamine
N-acetyl glutamic acid
Urine
1. Patient's age and sex are required.
2. Include family history, clinical condition (asymptomatic or acute episode), diet, and drug therapy information.
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.
3 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated | 60 days | |
Frozen (preferred) | 90 days |
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
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.
N-acetylglycine: < or =15.00 mmol/mol creatinine
N-acetyl alanine: < or =10.00 mmol/mol creatinine
N-acetylglutamic acid: < or =20.00 mmol/mol creatinine
N-acetylmethionine: < or =5.00 mmol/mol creatinine
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).
No significant cautionary statements
1. van Coster R. Aminoacylase I deficiency. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill Education; 2019. Accessed October 17, 2024. Available at https://ommbid.mhmedical.com/content.aspx?bookid=2709§ionid=225896774
2. Alessandri MG, Milone R, Casalini C, et al. Four years follow up of ACY1 deficient patient and pedigree study. Brain and Dev. 2018;40(7):570-575
3. Smolka V, Friedecky D, Kolarova J, et al. Aminoacylase 1 deficiency: case report on three affected siblings. AME Case Rep. 2023;8:18. doi:10.21037/acr-23-46
4. Sass JO, Mohr V, Olbrich H, et al. Mutations in ACY1, the gene encoding aminoacylase 1, cause a novel inborn error of metabolism. Am J Hum Genet. 2006;78(3):401-409. doi:10.1086/500563
Urine volumes equivalent to 0.25 to 0.50 mg of creatinine are spiked with the mixture of labeled internal standards, allowed to equilibrate, acidified, and then extracted. After evaporation, the dry residue is derivatized to butyl esters. Specimens are analyzed by capillary gas chromatography mass spectrometry selected ion monitoring using ammonia chemical ionization and a stable isotope dilution method.(Unpublished Mayo method)
Monday
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.
82542
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
AACYL | Aminoacylase-1 Deficiency, U | 104695-2 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
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 |
Change Type | Effective Date |
---|---|
New Test | 2025-03-04 |