Neuronal Ceroid Lipofuscinosis Type 1 (CLN1) : Palmitoyl-protein thioesterase 1 Enzyme Analysis

Test Information

This biochemical test is a quantitative measurement of palmitoyl-protein thioesterase 1 enzyme activity and can be used as a 1st tier test for patients with a clinical suspicion of Neuronal Ceroid Lipofuscinosis Type 1 (CLN1). Demonstration of deficient palmitoyl-protein thioesterase 1 enzyme activity is considered the gold standard to confirm a diagnosis of Neuronal Ceroid Lipofuscinosis Type 1 (CLN1).

In addition, this assay can be used to clarify molecular findings in the PPT1 gene and to monitor patients undergoing treatment.

Turnaround Time

2 weeks

CPT Code(s)

82657

Cost

$200


Enzymes

Palmitoyl-protein thioesterase 1

Clinical Information

The neuronal ceroid lipofuscinoses (CLN) are a group of conditions that are inherited in an autosomal recessive pattern. CLN1 is characterized by progressive microcephaly, contractures, developmental delay, psychiatric symptoms, and neurological degeneration including seizures and ataxia. Retinal and macular degeneration leads to blindness by the age of 2 years with diminished or abolished ERG results. Age of onset varies with infantile, late-infantile, juvenile and adult-onset forms of the disease with younger ages of onset typically associated with a more rapid progression of symptoms. The intracellular accumulation of lipopigments results in a characteristic microscopic pattern called granular osmiophilic deposits (GROD).

Indications

This test can be used to confirm a suspected neuronal ceroid lipofuscinosis 1 (CLN1) diagnosis. Prenatal diagnosis and carrier testing via enzyme analysis are not available.

Methodology

4-methylumbelliferyl substrate

Specimen Requirements

Enzyme activity can be measured in leukocytes, cultured fibroblasts, or dried blood spots. For leukocytes, please send 5-10 ml of whole blood in a green top (sodium heparin) tube. For dried blood spot collection, a minimum of three circles need to be filled in. Each circle should contain one drop of blood (about 100 microliters). See the link below for additional sample collection and handling instructions.

Transport Instructions

Whole blood samples (for leukocyte analysis) should be shipped at ambient temperature and must arrive at the laboratory within 24 hours of specimen collection.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Biochemical Testing, Enzyme Analysis, Individual Enzyme Assays
One Mother's Story

One Mother's Story

After a long three-year struggle trying to have children, our son, Charlie, was born on April 18, 2009. He was our miracle...perfect in every way! When Charlie was five days old, our pediatrician called to notify us that one of the numbers from the heel prick test was a bit high. We headed to the hospital that afternoon for more tests. I will never forget the following day. It was cool and crisp - not a cloud in the sky....

In The News