Mucopolysaccharidosis III, Three-Enzyme Panel, Blood Spot
Use
This test supports the biochemical diagnosis of mucopolysaccharidoses types IIIA, IIIB, and IIIC. It provides diagnostic testing for individuals with clinical signs and symptoms suspicious for these types. The assay detects enzyme deficiencies associated with mucopolysaccharidosis III (also known as Sanfilippo syndrome), which results in the excretion of heparan sulfate and is characterized by severe central nervous system (CNS) degeneration and mild physical symptoms. Onset usually occurs between ages 2 and 6, with severe neurologic degeneration by age 6 to 10 years. This test is not useful for carrier detection.
Special Instructions
The assay does not evaluate the enzyme for mucopolysaccharidosis IIID. Enzymatic analysis for MPS IIID is included in test MPS3W. If enzyme deficiencies are detected, additional biochemical or molecular testing is recommended to confirm a diagnosis. Patients' age and reason for the test are required. Inform consent documentation is necessary for New York clients.
Limitations
Results indicating enzyme deficiencies should prompt further biochemical or molecular analyses for verification, as abnormal results are not sufficient to establish a diagnosis. Individuals with pseudodeficiency alleles can show reduced enzyme activity, and heterozygosity cannot be reliably detected. The presence or absence of enzyme replacement therapy or hematopoietic stem cell transplant can influence enzyme level results.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 104112-8
- 104113-6
- 104114-4
- 104115-1
- 59462-2
- 18771-6
Result Turnaround Time
3-9 days
Related Documents
For more information, please review the documents below
Specimen
Dried Blood Spot
Volume
2 Blood spots
Minimum Volume
1 Blood spot
Container
Blood Spot Collection Card
Collection Instructions
Alternative collection from fingerstick for patients older than 1 year. Ensure at least 2 complete spots; dry horizontally at room temperature for 3 hours. Avoid heat/sunlight exposure and stacking wet specimens.
Storage Instructions
Keep specimen dry.
Causes for Rejection
Blood spot specimen with serum rings or multiple layers, unapproved filter papers, insufficient specimen volume.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 60 days |
| Frozen | 60 days |