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Test ID: TALDO Polyols, Quantitative, Urine

Useful For

Diagnosis of transaldolase (TALDO) deficiency or ribose-5-phosphate isomerase (RPI) deficiency

Reporting Name

Polyols, QN, U

Specimen Type

Urine


Specimen Required


Container/Tube: Plastic, 10-mL urine tube (T068)

Specimen Volume: 2 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

Additional Information: Patient's age is required.

Forms: New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 28 days
  Frozen  28 days

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 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. Both TALDO and RPI deficiency that have multisystem involvement are recently described disorders of this pathway.

 

TALDO 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 occur.

 

RPI 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.

 

Polyols analysis in urine is the method of choice for the biochemical diagnosis of TALDO and RPI deficiency. Abnormal results should be followed with either enzymatic or molecular genetic analysis.

Reference Values

 

0-11 months

1-3 years

4-17 years

≥18 years

Erythritol

<220

<267

<171

<99

Arabinitol

<140

<149

<97

<51

Ribitol

<31

<31

<17

<11

Sedoheptulose

<76

<27

<28

<22

 

Values are expressed in mmol/mol creatinine

Interpretation

An interpretive report is 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 or elsewhere, and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.

Clinical Reference

1. Online Mendelian Inheritance in Man. 606003. National Center for Biotechnology Information. Available at www.ncbi.nlm.nih.gov/Omim

2. Online Mendelian Inheritance in Man. 608611. National Center for Biotechnology Information. Available at www.ncbi.nlm.nih.gov/Omim

3. 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;36:997-1004

4. 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;74:745-751

5. Wamelink MM, Struys EA, Jakobs C: The biochemistry, metabolism and inherited defects of the pentose phosphate pathway: a review. J Inherit Metab Dis 2008;31:703-717

Day(s) and Time(s) Performed

Thursday; 8 a.m.

Analytic Time

3 days

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

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
TALDO Polyols, QN, U In Process

 

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) 59462-2
35830 Reviewed By No LOINC Needed

Method Name

Gas Chromatography/Mass Spectrometry (GC/MS)

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

mml-biochemical