Distinguishing between primary and secondary hyperoxaluria
Distinguishing between primary hyperoxaluria types 1, 2, and 3
Primary hyperoxalurias, classified into types 1, 2, and 3, are genetic disorders of oxalate metabolism characterized by increased urinary excretion of oxalic acid and kidney stone formation.
Secondary hyperoxaluria is an acquired condition resulting from either increased intake of dietary oxalate or altered intestinal oxalate absorption.
A diagnostic workup in an individual with hyperoxaluria demonstrates increased concentration of oxalate in urinary metabolite screening. If glycolate, glycerate, or 4-hydroxy-2-oxoglutarate is present, a primary hyperoxaluria is indicated.
Each type of primary hyperoxaluria is distinguished from the others based on the urine profile.
For more information see Hyperoxaluria Diagnostic Algorithm.
Gas Chromatography Mass Spectrometry (GC-MS)
Glycerate
Glycolate
Oxalate
PH1 (Primary Hyperoxaluria Type 1)
PH2 (Primary Hyperoxaluria Type 2)
Primary Hyperoxaluria Type 1 (PH1)
Primary Hyperoxaluria Type 2 (PH2)
4-hydroxy-2-oxoglutarate
HOG
HOGA1
PH3 (Primary Hyperoxaluria Type 3)
Primary Hyperoxaluria Type 3 (PH3)
For more information see Hyperoxaluria Diagnostic Algorithm.
Urine
1. Patient age is required.
2. Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 10 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
3. Immediately freeze specimen.
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Biochemical Genetics Test Request (T798)
-Renal Diagnostics Test Request (T830)
1.1 mL
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Frozen (preferred) | 90 days | |
Refrigerated | 14 days |
Distinguishing between primary and secondary hyperoxaluria
Distinguishing between primary hyperoxaluria types 1, 2, and 3
Primary hyperoxalurias, classified into types 1, 2, and 3, are genetic disorders of oxalate metabolism characterized by increased urinary excretion of oxalic acid and kidney stone formation.
Secondary hyperoxaluria is an acquired condition resulting from either increased intake of dietary oxalate or altered intestinal oxalate absorption.
For more information see Hyperoxaluria Diagnostic Algorithm.
Increased urinary oxalate frequently leads to kidney stone formation and kidney insufficiency. Identifying the cause of hyperoxaluria has important implications in therapy, management, and prognosis.
Hyperoxalurias are classified as primary and secondary. Primary hyperoxaluria is an inherited disorder of oxalate metabolism, while secondary hyperoxaluria is an acquired condition resulting from either increased intake of dietary oxalate or altered intestinal oxalate absorption. Primary hyperoxalurias are classified into types 1, 2, and 3.
Hyperoxaluria type 1 (PH1) is an autosomal recessive disorder resulting in a deficiency of peroxisomal alanine:glyoxylate aminotransferase due to variants in the AGXT gene. It is characterized by increased urinary oxalic, glyoxylic, and glycolic acids. PH1 is the most common type with manifestations that include deposition of calcium oxalate in the kidneys (nephrolithiasis, nephrocalcinosis) and kidney failure. Calcium oxalate deposits can be further deposited in other tissues, such as the heart and eyes, and lead to a variety of additional symptoms. Age of onset is variable with a small percentage of patients presenting in the first year of life with failure to thrive, nephrocalcinosis, and metabolic acidosis. Approximately half of affected individuals show manifestations of PH1 in late childhood or early adolescence, and the remainder present in adulthood with recurrent kidney stones. Some individuals with PH1 respond to supplemental pyridoxine therapy.
Hyperoxaluria type 2 (PH2) is due to a defect in GRHPR gene resulting in a deficiency of the enzyme hydroxypyruvate reductase. PH2 is inherited in an autosomal recessive manner and is identified by an increase in urinary oxalic and glyceric acids. Like PH1, PH2 is characterized by deposition of calcium oxalate in the kidneys (nephrolithiasis, nephrocalcinosis), and kidney failure. Most individuals have symptoms of PH2 during childhood, and it is thought that PH2 is less common than PH1.
Hyperoxaluria type 3 (PH3), due to recessive variants in HOGA1 (formerly DHDPSL), occurs in a small percentage of individuals with primary hyperoxaluria. HOGA1 encodes a mitochondrial 4-hydroxy-2-oxoglutarate aldolase that catalyzes the 4th step in the hydroxyproline pathway. PH3 is characterized biochemically by increased urinary excretion of oxalate and 4-hydroxy-2-oxoglutarate (HOG). As with PH types 1 and 2, PH type 3 is characterized by calcium-oxalate deposition in the kidneys or kidney stone formation. Most individuals with PH3 have early onset disease with recurrent kidney stones and urinary tract infections as common symptoms. Kidney failure is not a characteristic of PH3. Of note, individuals with heterozygous variants in HOGA1 can have variable and intermittent elevations of urine oxalate.
Secondary hyperoxalurias are due to hyperabsorption of oxalate (enteric hyperoxaluria); total parenteral nutrition in premature infants; ingestion of oxalate, ascorbic acid, or ethylene glycol; or pyridoxine deficiency, and may respond to appropriate therapy.
A diagnostic workup in an individual with hyperoxaluria demonstrates increased concentration of oxalate in urinary metabolite screening. If glycolate, glycerate, or HOG is present, a primary hyperoxaluria is indicated. Confirmatory testing includes molecular analysis for PH1, PH2, or PH3 (CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; refer to the Hyperoxaluria Diagnostic Algorithm for specific Gene List IDs).
GLYCOLATE
< or =17 years: < or =75 mg/g creatinine
> or =18 years: < or =50 mg/g creatinine
GLYCERATE
< or =31 days: < or =75 mg/g creatinine
32 days - 4 years: < or =125 mg/g creatinine
5 - 10 years: < or =55 mg/g creatinine
> or =11 years: < or =25 mg/g creatinine
OXALATE
< or =6 months: < or =400 mg/g creatinine
7 months - 1 year: < or =300 mg/g creatinine
2 - 6 years: < or =150 mg/g creatinine
7 - 10 years: < or =100 mg/g creatinine
> or =11 years: < or =75 mg/g creatinine
4-HYDROXY-2-OXOGLUTARATE (HOG)
< or =10 mg/g creatinine
Increased concentrations of oxalate and glycolate indicate type 1 hyperoxaluria.
Increased concentrations of oxalate and glycerate indicate type 2 hyperoxaluria.
Increased concentrations of oxalate and 4-hydroxy-2-oxoglutarate indicate type 3 hyperoxaluria.
Increased concentrations of oxalate with normal concentrations of glycolate, glycerate, and 4-hydroxy-2-oxoglutarate indicate secondary hyperoxaluria.
Ascorbic acid (vitamin C) will falsely elevate oxalic acid results.
1. Bhasin B, Urekli HM, Atta MG. Primary and secondary hyperoxaluria: Understanding the enigma. World J Nephrol. 2015;4(2):235-244. doi:10.5527/wjn.v4.i2.235
2. Lorenzo V, Torres A, Salido E. Primary hyperoxaluria. Nefrologia. 2014;34(3):398-412
3. Milliner DS, Harris PC, Cogal AG, et al. Primary hyperoxaluria type 1. In: Adam MP, Mirzaa GM, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2002. Updated February 10, 2022. Accessed August 28, 2023. Available at: www.ncbi.nlm.nih.gov/books/NBK1283/
4. Rumsby G, Hulton SA. Primary hyperoxaluria type 2. In: Adam MP, Mirzaa GM, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2008. Updated December 21, 2017. Accessed August 28, 2023. Available at: www.ncbi.nlm.nih.gov/books/NBK2692/
5. Milliner DS, Harris PC, Lieske JC. Primary hyperoxaluria type 3. In: Adam MP, Mirzaa GM, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2015. Updated February 9, 2023. Accessed August 28, 2023. Available at: www.ncbi.nlm.nih.gov/books/NBK316514/
6. Fraser AD: Importance of glycolic acid analysis in ethylene glycol poisoning. Clin Chem. 1998;44(8):1769
Urine samples corresponding to 0.25 mg of creatinine (not to exceed 1 mL of urine) are oximated to stabilize one of the target analytes, 4-hydroxy-2-oxoglutaric. The urine is then acidified and extracted. After evaporation, the dry residue is silylated and analyzed by capillary gas chromatography mass spectrometry.(Unpublished Mayo method)
Wednesday
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.
82542
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
HYOX | Hyperoxaluria Panel, U | 53710-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
50592 | Glycolate | 13751-3 |
50593 | Glycerate | 13749-7 |
50594 | Oxalate | 13483-3 |
29984 | Reviewed By | 18771-6 |
29982 | Interpretation | 59462-2 |
38049 | 4-hydroxy-2-oxoglutarate | 13678-8 |