Neuronal Ceroid Lipofuscinosis, Two-Enzyme Panel, Blood Spot
Use
The Neuronal Ceroid Lipofuscinoses (NCL) comprise a group of recessively inherited neurodegenerative disorders involved in lysosomal protein catabolism. This test provides diagnostic testing for individuals with clinical signs and symptoms suspicious for neuronal ceroid lipofuscinosis 1 or 2 (CLN1 or CLN2). The test supports the biochemical diagnosis of these conditions, specifically focusing on deficiencies in palmitoyl-protein thioesterase 1 (PPT1) for CLN1 and tripeptidyl peptidase 1 (TPP1) for CLN2. These deficiencies lead to the characteristic accumulation of auto-fluorescent storage material in the brain and tissues.
Special Instructions
Not provided.
Limitations
Carrier status (heterozygosity) for these conditions cannot be reliably detected. Abnormal enzyme levels can result from pseudodeficiency alleles. Results should be interpreted in conjunction with additional biochemical or molecular genetic analyses, as abnormal results on their own are not sufficient to establish a diagnosis. Enzyme levels might be normal in individuals receiving enzyme replacement therapy or who have undergone hematopoietic stem cell transplant.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
Palmitoyl-protein thioesterase 1
ProteinTripeptidyl peptidase 1
Protein
LOINC Codes
- 101348-1 - NCLBS DBS
- 42349-1
- 59246-9 - PPT DBS-cCnc
- 72498-9 - Tripeptidyl peptidase I DBS-cCnc
- 59462-2 - Clinical biochemist review
- 18771-6 - Provider signing name
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
An alternative blood collection option for a patient older than 1 year is a fingerstick. At least 2 spots should be complete and unpunched. Let blood dry on filter paper at room temperature in a horizontal position for a minimum of 3 hours. Do not expose specimen to heat or direct sunlight. Do not stack wet specimens. Keep specimen dry.
Storage Instructions
Refrigerated preferred; keep dry.
Causes for Rejection
Blood spot specimen that shows serum rings or has multiple layers. Insufficient specimen. Unapproved filter papers.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 60 days |
| Frozen | 60 days |