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Test ID PDGP Peroxisomal Disorder Gene Panel, Varies


Advisory Information


Preliminary biochemical testing may be helpful in making a diagnosis. Recommended first-tier biochemical testing for peroxisomal disorders analyzes very long-chain fatty acids; order POX / Fatty Acid Profile, Peroxisomal (C22-C26), Serum.



Shipping Instructions


Specimen preferred to arrive within 96 hours of collection.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information: Ambient (preferred)/Refrigerated


Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing  (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

2. Molecular Genetics: Biochemical Disorders Patient Information (T527) in Special Instructions

Useful For

Follow up of abnormal biochemical result, usually very long-chain fatty acid test consistent with peroxisomal disorder

 

Establishing a molecular diagnosis for patients with peroxisomal disorders

 

Identifying variants within genes known to be associated with peroxisomal disorders, allowing for predictive testing of at-risk family members

Testing Algorithm

See Newborn Screen Follow-up for X-Linked Adrenoleukodystrophy in Special Instructions.

Method Name

Custom Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing.

Reporting Name

Peroxisomal Disorder Gene Panel

Specimen Type

Varies

Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Clinical Information

Peroxisomes are responsible for catabolic actions of cells, including beta oxidation of very long-chain fatty acids, and anabolic actions, including biosynthesis of bile acids and plasmalogens. Peroxisomal disorders can be categorized into 2 major groups based on the function that is disrupted: peroxisomal biogenesis disorders and single peroxisomal enzyme deficiencies.

 

Peroxisomal biogenesis disorders are caused by defective assembly of the organelle resulting in some amount of deficient functional peroxisomes. Severity of disease is dependent on amount of remaining functional peroxisomes. Peroxisomal biogenesis disorders include those in the Zellweger spectrum: Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease. Clinical features are usually progressive and include developmental delay, liver disease, blindness, and deafness. Severity is variable with Zellweger syndrome being the most severe and infantile Refsum disease being the least severe.

 

These are due to variants in the PEX genes that are responsible for encoding proteins for peroxisome assembly.

 

Peroxisomal enzyme deficiencies cause a disruption in peroxisomal function, although the organelles remain intact. The most common peroxisomal disorder, X-linked adrenoleukodystrophy, is an enzyme deficiency due to variants in the ABCD1 gene. Other enzyme deficiencies include rhizomelic chondrodysplasia type 2 and 3, and congenital bile acid synthesis defect.

 

This panel includes sequencing of 30 genes related to both peroxisomal biogenesis disorders and enzyme deficiencies. 

Reference Values

An interpretive report will be provided.

Interpretation

All detected alterations are evaluated according to American College of Medical Genetics and Genomics (ACMG) recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.

Clinical Reference

1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015 May;17(5):405-424

2. Waterham, HR, Ebberink MS: Genetics and molecular basis of human peroxisome biogenesis disorders. Biochim Biophys Acta. 2012;1822(9):1430-1441

3. Wanders RJ: Metabolic and molecular basis of peroxisomal disorders: a review. Am J Med Genet A. 2004;126A(4):355-375

4. Wanders RJ, Waterham HR: Peroxisomal disorders: the single peroxisomal enzyme deficiencies. Biochim Biophys Acta. 2006;1763(12):1707-1720

5. Fidaleo M: Peroxisomes and peroxisomal disorders: the main facts. Exp Toxicol Pathol. 2010;62(6):615-625 

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

81443

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PDGP Peroxisomal Disorder Gene Panel In Process

 

Result ID Test Result Name Result LOINC Value
608560 Test Description 62364-5
608561 Specimen 31208-2
608562 Source 31208-2
608563 Result Summary 50397-9
608564 Result 82939-0
608565 Interpretation 69047-9
608566 Resources In Process
608567 Additional Information 48767-8
608568 Method 85069-3
608569 Genes Analyzed 48018-6
608570 Disclaimer 62364-5
608571 Released By 18771-6