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HelpTest Code TALDO Polyols, Quantitative, Urine
Useful For
Diagnosing deficiencies of transaldolase, transketolase, sedoheptulose, or ribose-5-phosphate isomerase
Reporting Name
Polyols, QN, USpecimen Type
UrineNecessary Information
1. Patient's 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.
Specimen Required
Supplies: Urine Tubes, 10 mL (T068)
Specimen Volume: 2 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 28 days | |
| Frozen | 28 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Genetics Test Information
This is a screening test for disorders of the pentose phosphate pathway such as transaldolase deficiency, transketolase deficiency, sedoheptulokinase deficiency, or ribose-5-phosphate isomerase deficiency.
Clinical Information
Polyols are sugar alcohols that have been identified in blood, urine, and cerebrospinal fluid. Characteristic patterns of abnormal polyols may suggest a disorder of the pentose phosphate pathway (PPP), including transaldolase (TALDO) deficiency, transketolase, and ribose-5-phosphate isomerase (RPI) deficiency. The PPP is involved in carbohydrate metabolism and is present in the cytosol of all cells. Two specific functions of the PPP are the production of nicotinamide adenine dinucleotide phosphate (NADPH[+]) and the synthesis of ribose-5-phosphate, a molecule necessary for nucleotide and nucleic acid synthesis. TALDO, transketolase, and RPI deficiency, which have multisystem involvement are recently described disorders of this pathway. Sedoheptulokinase deficiency is also recently described but it’s correlation to disease is unclear as only two unrelated patients from consanguineous families been reported to date. These 2 patients had different multisystem involvement.(1)
Transaldolase deficiency is an autosomal recessive disorder caused by a reduction of the enzyme transaldolase. Clinical manifestations are characterized by severe neonatal liver failure, coagulopathy, low serum protein, hypoglycemia, high ammonia, progressive myocardial hypertrophy, and abnormal lactate dehydrogenase with remarkably normal or low transaminases.
Patients may present in the antenatal period with maternal HELLP syndrome (hemolysis, elevated liver enzymes, low platelets), hydrops fetalis and oligohydramnios, dysmorphic features, cutis laxa, and hypertrichosis. The clinical course is variable, but acute liver failure with normal transaminases is a common finding. Initially, hepatomegaly is absent, but the spleen may be enlarged. Later, hepatomegaly with liver cirrhosis and mild kidney failure occurs.
Ribose-5-phosphate isomerase deficiency is an autosomal recessive disorder caused by a deficiency of the enzyme ribose-5-phosphate isomerase. Clinical manifestations include neurological deficits such as slow progressing leukoencephalopathy and neuropathy. Additionally, spasticity, ataxia, epilepsy, regression, and delayed psychomotor development have been described.
Transketolase deficiency is an autosomal recessive disorder characterized by short stature, developmental delay, and congenital heart defects. Dependent on thiamine, transketolase is directly involved in the branch of the pathway that channels excess sugar phosphates to glycolysis.(2) Characteristic polyol patterns in both urine and plasma include elevations of arabitol/xylitol, ribitol, and erythritol. Transketolase deficiency is caused by deleterious biallelic variants in TKT.
Sedoheptulokinase deficiency is an autosomal recessive condition characterized by increased excretion of erythritol and sedoheptulose.(3) Relationship to disease is yet unclear as only 2 patients have been described in the literature.
Polyols analysis in urine is the method of choice for the biochemical diagnosis of TALDO, transketolase, and RPI deficiency. Abnormal results should be followed with either enzymatic or molecular genetic analysis.
Reference Values
ERYTHRITOL
≤11 months: <220 mmol/mol creatinine
1-3 years: <267 mmol/mol creatinine
4-17 years: <171 mmol/mol creatinine
>or =18 years: <99 mmol/mol creatinine
ARABINITOL
≤11 months: <140 mmol/mol creatinine
1-3 years: <149 mmol/mol creatinine
4-17 years: <97 mmol/mol creatinine
>or =18 years: <51 mmol/mol creatinine
RIBITOL
≤11 months: <31 mmol/mol creatinine
1-3 years: <31 mmol/mol creatinine
4-17 years: <17 mmol/mol creatinine
>or =18 years: <11 mmol/mol creatinine
SEDOHEPTULOSE
≤11 months: <76 mmol/mol creatinine
1-3 years: <27 mmol/mol creatinine
4-17 years: <28 mmol/mol creatinine
>or =18 years: <22 mmol/mol creatinine
Interpretation
An interpretive report will be provided.
All profiles are reviewed by the laboratory director and interpretation is based on pattern recognition. A detailed interpretation is given, including an overview of the results and of their significance, a correlation to available clinical information, elements of differential diagnosis, recommendations for additional biochemical testing and in vitro confirmatory studies (enzyme assay, molecular analysis), name and phone number of key contacts who may provide these studies at Mayo Clinic or elsewhere, and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.
Cautions
A positive test result is diagnostic of transaldolase deficiency or ribose-5-phosphate isomerase deficiency; however, it is strongly recommended to follow-up with molecular analysis.
Clinical Reference
1. Wamelink MM, Ramos RJ, van den Elzen AP, et al. First two unrelated cases of isolated sedoheptulokinase deficiency: A benign disorder?. J Inherit Metab Dis. 2015;38(5):889-894. doi:10.1007/s10545-014-9809-
2. OMIM: 617044. Short Stature, Developmental Delay, and Congenital Heart Defects; SDDHD. Johns Hopkins University; 2016. Last updated April 07, 2021, Accessed September 27, 2024. Available at www.omim.org/entry/617044
3. OMIM: 617213. Sedoheptulokinase Deficiency; SHPKD. Johns Hopkins University; 2016. Accessed September 27, 2024. Available at www.omim.org/entry/617213
4. Eyaid W, Al Harbi T, Anazi S, et al. Transaldolase deficiency: report of 12 new cases and further delineation of the phenotype. J Inherit Metab Dis. 2013;36(6):997-1004
5. Huck JH, Verhoeven NM, Struys EA, et al. Ribose-5-phosphate isomerase deficiency: new inborn error in the pentose phosphate pathway associated with a slowly progressive leukoencephalopathy. Am J Hum Genet. 2004;74(4):745-751
6. Stincone A, Prigione A, Cramer T, et al. The return of metabolism: biochemistry and physiology of the pentose phosphate pathway. Biol Rev Camb Philos Soc. 2015;90(3):927-963. doi:10.1111/brv.12140
7. Wamelink MC, Valayannopoulos V, Jakobs C. Ribose-5-phosphate isomerase deficiency and transaldolase deficiency. 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 27, 2024. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225081431&bookid=2709
Method Description
Urine specimens are spiked with a mixture of labeled internal standards, allowed to equilibrate, and evaporated. The dry residue is derivatized to form trimethylsilyl esters then extracted with hexane. Specimens are analyzed by gas chromatography mass spectrometry, selected ion monitoring using ammonia chemical ionization and a stable isotope dilution method.(Jansen G, Muskiet F, Schierbeek H, et al. Capillary gas chromatography profiling of urinary, plasma, and erythrocyte sugars and polyols as their trimethylsilyl derivatives, preceded by a simple and rapid prepurification method. Clin Chim Acta 1986;157(3):277-294, Kaur P, Wamelink MMC, van der Knaap MS, et al. Confirmation of a rare genetic leukoencephalopathy due to a novel bi-allelic variant in RPIA. Eur J Med Genet. 2019;62(8):103708. doi:10.1016/j.ejmg.2019.103708)
Day(s) Performed
Tuesday; Friday
Report Available
3 to 7 daysSpecimen Retention Time
3 monthsPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
82542
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TALDO | Polyols, QN, U | 74447-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 35824 | Erythritol | 48107-7 |
| 35825 | Arabinitol | 47829-7 |
| 35826 | Ribitol | 47884-2 |
| 35827 | Sedoheptulose | 78967-7 |
| 35829 | Interpretation (TALDO) | 74448-2 |
| 35830 | Reviewed By | 18771-6 |
Method Name
Gas Chromatography Mass Spectrometry (GC-MS)
Highlights
Transaldolase (TALDO) deficiency, transketolase deficiency, and ribose-5-phosphate (RPI) deficiency are 3 recently described multisystem disorders of the pentose phosphate pathway.
Correlation to disease manifestations is unclear in sedoheptulokinase deficiency.
This test is the method of choice for detecting TALDO, transketolase, and RPI deficiency.
Forms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.