PBG Deaminase, WB - Clinical Genetic Test - GTR

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PBG Deaminase, WB

Clinical Genetic Test

offered by

Mayo Clinic Laboratories

View lab's test page

GTR Test Accession: GTR000613095.1

INHERITED DISEASECONNECTIVE TISSUEDIGESTIVE SYSTEM ... View more

Last updated in GTR: 2023-11-08

Last annual review date for the lab: 2023-05-30

At a Glance

Test purpose:

Diagnosis

Conditions (1):

Acute intermittent porphyria

Analytes (1):

porphobilinogen deaminase

Methods (1):

Biochemical Genetics - Analyte: Fluorometry

Target population:

Confirmation of a diagnosis of acute intermittent porphyria.

Clinical validity:

Not provided

Clinical utility:

Establish or confirm diagnosis

Ordering Information

Offered by:

Mayo Clinic Laboratories
View lab's website
View lab's test page

Test short name:

PBGD_

Specimen Source:

Peripheral (whole) blood
View specimen requirements

Who can order:

Genetic Counselor
Health Care Provider
Licensed Dentist
Licensed Physician
Nurse Practitioner
Physician Assistant
Public Health Mandate
Registered Nurse

Test Order Code:

PBGD_
View other test codes

LOINC codes:

**LOINC codes notice

Lab contact:

Gisele (Gessi) Bentz Pino, MS, CGC, Certified Genetic counselor, CGC, Genetic Counselor
biochemicalgenetics@mayo.edu
1-800-533-1710

Contact Policy:

Laboratory can only accept contact from health care providers. Patients/families are encouraged to discuss genetic testing options with their health care provider.

How to Order:

https://www.mayocliniclabs.com/test-catalog/Overview/88925#Specimen
Order URL

Test development:

Test developed by laboratory (no manufacturer test name)

Informed consent required:

Based on applicable state law

Pre-test genetic counseling required:

Decline to answer

Post-test genetic counseling required:

Decline to answer

Recommended fields not provided:

Test strategy

Conditions

Total conditions: 1

Condition/Phenotype	Identifier

Test Targets

Analytes

Total analytes: 1

Analyte	Associated Condition

Methodology

Total methods: 1

Method Category

Test method

Instrument *

Analyte

Fluorometry

* Instrument: Not provided

Clinical Information

Test purpose:

Diagnosis

Clinical utility:

Establish or confirm diagnosis

View citations (1)

Tortorelli S, Kloke K, Raymond K. Disorders of porphyrin metabolism. In: Dietzen DJ, Bennett MJ, Wong ECC, eds. Biochemical and Molecular Basis of Pediatric Disease. 4th ed. AACC Press; 2010:307-324

Target population:

Confirmation of a diagnosis of acute intermittent porphyria.

View citations (3)

Formate assay in body fluids: application in methanol poisoning. Makar AB, et al. Biochem Med. 1975;13(2):117-26. doi:10.1016/0006-2944(75)90147-7. PMID: 1. Tortorelli S, Kloke K, Raymond K. Disorders of porphyrin metabolism. In: Dietzen DJ, Bennett MJ, Wong ECC, eds. Biochemical and Molecular Basis of Pediatric Disease. 4th ed. AACC Press; 2010:307-324.
Delineation of the intimate details of the backbone conformation of pyridine nucleotide coenzymes in aqueous solution. Bose KS, et al. Biochem Biophys Res Commun. 1975;66(4):1173-9. doi:10.1016/0006-291x(75)90482-9. PMID: 2. Nuttall KL, Klee GG. Analytes of hemoglobin metabolism-porphyrins, iron, and bilirubin. In: Burtis CA, Ashwood ER, eds. Tietz Textbook of Clinical Chemistry. 5th ed. WB Saunders Company; 2001:584-607.
Metal substitutions incarbonic anhydrase: a halide ion probe study. Smith RJ, et al. Biochem Biophys Res Commun. 1975;66(4):1281-6. doi:10.1016/0006-291x(75)90498-2. PMID: 3. Anderson KE, Sassa S, Bishop DF, Desnick RJ. Disorders of heme biosynthesis: X-linked sideroblastic anemia and the porphyrias. 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 May 6, 2022. Available at https://ommbid.mhmedical.com/content.aspx?bookid=2709§ionid=225540906.

Variant Interpretation:

What is the protocol for interpreting a variation as a VUS?
N/A

Will the lab re-contact the ordering physician if variant interpretation changes?
Not provided. N/A

Research:

Is research allowed on the sample after clinical testing is complete?
Research testing is only performed under IRB approved protocol with an opt-out policy in place.

Recommended fields not provided:

Clinical validity, Are family members with defined clinical status recruited to assess significance of VUS without charge?, Will the lab re-contact the ordering physician if variant interpretation changes?, Sample negative report, Sample positive report

Technical Information

Test Procedure:

Measurement of porphobilinogen deaminase (PBGD) activity is based on the measurement of the rate of synthesis of uroporphyrin from porphobilinogen (PBG) in incubated, lysed erythrocytes. Low yield of uroporphyrin from PBG indicates a deficiency of PBGD.

View citations (1)

Bustad HJ, Vorland M, Rønneseth E, Sandberg S, Martinez A, Toska K. Conformational stability and activity analysis of two hydroxymethylbilane synthase mutants, K132N and V215E, with different phenotypic association with acute intermittent porphyria. Biosci Rep. 2013;33(4). doi:10.1042/BSR20130045. Epub 2013 Aug 08. PMID: 23815679.

Availability:

Tests performed
Entire test performed in-house

Analytical Validity:

Accuracy was assessed by analysis of normal and abnormal specimens; all samples were clinically concordant. Intra assay precision was performed at 3 levels: CV results ranged from 0.16% to 0.26% (N=5 each). Inter assay precision was performed at 2 levels: CV results were 5.7% and 7.3% (N=5 each). The analytical … View more

Assay limitations:

A normal result does not rule-out acute intermittent porphyria; 5% to 10% of affected individuals will have normal erythrocyte porphobilinogen deaminase activity. Additionally, enzyme activity may be increased during an acute attack; therefore, the enzyme level should be assessed when the patient is asymptomatic.

Proficiency testing (PT):

Is proficiency testing performed for this test?
Yes

Method used for proficiency testing:
Formal PT program

PT Provider:
IPNET

Description of PT method:
Formal PT program.

Description of internal test validation method: Help
This test was laboratory developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements.

VUS:

Software used to interpret novel variations
N/A

Laboratory's policy on reporting novel variations
N/A

Recommended fields not provided:

Test Confirmation, Citations to support assay limitations, Citations to support internal test validation method, Citations for Analytical validity, Major CAP category, CAP category, CAP test list

Regulatory Approval

FDA Review:

Category: FDA exercises enforcement discretion

Additional Information

Reviews:

Genereviews

PubMed Clinical Queries

Clinical resources:

Molecular resources:

View HMBS variations in ClinVar

RefSeqGene

Coriell Institute for Medical Research

Practice guidelines:

Orphanet, 2007

Consumer resources:

Genetic Alliance

MalaCards

MedlinePlusGenetics (GHR)

NCATS Office of Rare Diseases Research (GARD)

MedlinePlus

IMPORTANT NOTE: NIH does not independently verify information submitted to GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.