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Test ID: UPGC Uroporphyrinogen III Synthase (Co-Synthase), Erythrocytes

Reporting Name

Uroporphyrinogen III Synthase, RBC

Useful For

Diagnosis of congenital erythropoietic porphyria

 

This test is not useful for diagnosis of acute intermittent porphyria (AIP).

Clinical Information

The porphyrias are a group of inherited disorders resulting from enzyme defects in the heme biosynthetic pathway. Congenital erythropoietic porphyria (CEP) is an extremely rare, autosomal recessive porphyria that typically presents in early infancy. Also known as Gunther disease, CEP results from a deficiency of uroporphyrinogen III (co-) synthase (UROIIIS). In most cases, the disorder is suggested during the first few days or weeks of life by pink, violet, or brown urinary staining of diapers. Clinical symptoms include hemolytic anemia, hepatosplenomegaly, skin photosensitivity, scarring and blistering, red or brown dental discoloration (erythrodontia), and hypertrichosis (excess body hair). Growth and cognitive developmental delays are commonly observed in individuals with CEP. A few cases of adult-onset CEP have been reported, typically associated with a myelodysplastic syndrome.

 

The workup of patients with a suspected porphyria is most effective when following a stepwise approach. Molecular confirmatory testing is available on a clinical basis; order CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify UROS Gene List ID: IEMCP-8W4945. For more information see Porphyria (Cutaneous) Testing Algorithm or call 800-533-1710 to discuss testing strategies.

Interpretation

Abnormal results are reported with a detailed interpretation that may include an overview of the results and their significance, a correlation to available clinical information provided with the specimen, differential diagnosis, recommendations for additional testing when indicated and available, and a phone number to reach a laboratory director in case the referring physician has additional questions.

Testing Algorithm

The following algorithms are available:

-Porphyria (Acute) Testing Algorithm

-Porphyria (Cutaneous) Testing Algorithm

Report Available

3 to 9 days

Day(s) Performed

Wednesday

Clinical Reference

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

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

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 September 6, 2024. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225540906&bookid=2709

4. Erwin AL, Desnick RJ. Congenital erythropoietic porphyria: Recent advances. Mol Genet Metab. 2019;128(3):288-297. doi:10.1016/j.ymgme.2018.12.008

Method Name

High-Performance Liquid Chromatography (HPLC)

Specimen Type

WB Heparin


Ordering Guidance


This test is most appropriately used for pediatric patients.

 

This test measures uroporphyrinogen (UPG) III synthase to confirm congenital erythropoietic porphyria, which is typically seen in early infancy. It does not measure UPG I synthase (also known as porphobilinogen deaminase), the enzyme deficient in acute intermittent porphyria (AIP). For AIP (and UPG I synthase), order PBGD_ / Porphobilinogen Deaminase, Whole Blood.



Necessary Information


1. Include a list of medications the patient is currently taking.

2. Date of transfusion, if performed



Specimen Required


All porphyrin tests on erythrocytes can be performed on one collection tube.

 

Patient Preparation: Patient must not consume any alcohol for 24 hours before specimen collection.

Container/Tube: Green top (sodium or lithium heparin)

Specimen Volume: 4 mL

Collection Instructions: Immediately place specimen on wet ice.


Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
WB Heparin Refrigerated 7 days

Reference Values

≥75 Relative Units (normal)

 

For more information see The Heme Biosynthetic Pathway

Test Classification

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

CPT Code Information

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
UPGC Uroporphyrinogen III Synthase, RBC 11066-8

 

Result ID Test Result Name Result LOINC Value
80288 Uroporphyrinogen III Synthase, RBC 11066-8

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:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.

Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Behavioral, mml-Neuromuscular, mml-Pediatric, mml-Neurometabolic