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Test Code CTSU Ceramide Trihexosides and Sulfatides, Random, Urine


Necessary Information


Biochemical Genetics Patient Information (T602) is recommended. This information aids in providing a more thorough interpretation of results. Send information with specimen.



Specimen Required


Patient Preparation: Baby wipes or wipes containing soaps and lotions should not be used prior to urine collection because these may interfere with results.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube: Plastic, 5-mL urine tube

Specimen Volume: 2 mL

Collection Instructions: Collect a first-morning, random urine specimen.

Specimen Stability Information: Refrigerated (preferred) 45 days/Ambient 45 days/Frozen 19 months


Useful For

Identifying patients with Fabry disease

 

Identifying patients with metachromatic leukodystrophy

 

Identifying patients with saposin B deficiency

 

Identifying patients with multiple sulfatase deficiency

 

Identifying patients with mucolipidosis II (I-cell disease)

Testing Algorithm

For information see:

-Fabry Disease Diagnostic Testing Algorithm

 

If the patient has abnormal newborn screening results for Fabry disease. Refer to the appropriate ACMG Newborn Screening ACT Sheet.(1)

Method Name

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)

Reporting Name

Ceramide Trihex and Sulfatide, U

Specimen Type

Urine

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 45 days
  Ambient  45 days
  Frozen 

Reference Values

An interpretive report will be provided.

Interpretation

The pattern of ceramide trihexosides or sulfatide excretion will be described. A normal pattern of excretion suggests absence of these diseases (see Cautions).

 

Evidence of ceramide trihexoside accumulation suggests decreased or deficient alpha-galactosidase activity, see Fabry Disease Testing Algorithm.

 

Evidence of sulfatide accumulation suggests decreased or deficient arylsulfatase A activity. Follow-up with the specific enzyme assay is recommended:

-ARSAW / Arylsulfatase A, Leukocytes

-ARSU / Arylsulfatase A, 24 Hour, Urine

To exclude multiple sulfatase deficiency (MSD), determination of iduronate-2-sulfatase activity is recommended.

-I2SWB / Iduronate-2-Sulfatase, Leukocytes

-I2SB / Iduronate-2-Sulfatase, Blood Spot

 

Evidence of both ceramide trihexoside and sulfatide accumulation suggests a diagnosis of mucolipidosis II (I-cell disease) or saposin B deficiency. Follow-up testing to rule-out I-cell disease may include molecular analysis of the GNPTAB gene or measurement of serum hydrolases (NAGS / Hexosaminidase A and Total Hexosaminidase, Serum).

 

Molecular genetic testing is required to confirm saposin B deficiency.

 

For more information see Lysosomal Storage Disorders Diagnostic Algorithm, Part 2.

Clinical Reference

1. ACMG Newborn Screening ACT Sheets. Accessed October 30, 2023. Available at www.acmg.net/ACMG/Medical-Genetics-Practice-Resources/ACT_Sheets_and_Algorithms/ACMG/Medical-Genetics-Practice-Resources/ACT_Sheets_and_Algorithms.aspx?hkey=9d6bce5a-182e-42a6-84a5-b2d88240c508

2. Desnick RJ, Ioannou YA, Eng CM. Alpha-galactosidase A deficiency: Fabry disease. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw Hill; 2019. Accessed November 29, 2023. Available at https://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=225546984

3. Kuchar L, Ledvinova J, Hrebicek M, et al. Prosaposin deficiency and saposin B deficiency (activator-deficient metachromatic leukodystrophy): report on two patients detected by analysis of urinary sphingolipids and carrying novel PSAP gene mutations. Am J Med Genet A. 2009;149A(4):613-621

4. Mehta A, Hughes DA. Fabry disease. In: Adam MP, Feldman J, Mirzaa GM, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2002. Updated March 9, 2023. Accessed November 29, 2023. Available at www.ncbi.nlm.nih.gov/books/NBK1292/

5. Schlotawa L, Ennemann EC, Radhakrishnan K, et al. SUMF1 mutations affecting stability and activity of formylglycine generating enzyme predict clinical outcome in multiple sulfatase deficiency. Eur J Hum Genet. 2011;19(3):253-261

6. Gieselmann V, Ingeborg K. Metachromatic leukodystrophy. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw Hill; 2019. Accessed November 29, 2023. Available at https://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=225546629

7. Leroy JG, Cathey SS, Friez MJ. GNPTAB-related disorders. In: Adam MP, Feldman J, Mirzaa GM, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2008. Updated August 29, 2019. Accessed November 29, 2023. Available at www.ncbi.nlm.nih.gov/books/NBK1828/

Day(s) Performed

Monday

Report Available

8 to 15 days

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

83789

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CTSU Ceramide Trihex and Sulfatide, U 59462-2

 

Result ID Test Result Name Result LOINC Value
606148 Interpretation 59462-2
606149 Reviewed By 18771-6