Sorted By Test Name - Mayo Medical Laboratories

Purine and Pyrimidine Panel, Urine
Clinical Information: Purines (adenine, guanine, xanthine, hypoxanthine) and pyrimidines (uracil,
thymine, cytosine, orotic acid) are involved in all biological processes, providing the basis for storage,
transcription, and translation of genetic information as RNA and DNA. Purines are required by all cells
for growth and survival and also play a role in signal transduction and translation. Purines and
pyrimidines originate primarily from endogenous synthesis, with dietary sources playing only a minor
role. The end product of purine metabolism is uric acid (2,6,8-trioxypurine), which must be excreted
continuously to avoid toxic accumulation. Due to the various roles these compounds play, the enzymes
catalyzing purine and pyrimidine metabolism function as "housekeeping" enzymes. Accordingly,
disorders of purine and pyrimidine metabolism can involve all organ systems at any age. Lesch-Nyhan
syndrome (complete deficiency of hypoxanthine-guanine phosphoribosyltransferase) was described in
1964 as the first disorder of purine metabolism. It is an X-linked disorder characterized by severe
neurologic impairment, the development of a compulsive self-destructive behavior, and uric acid
nephropathy. The diagnosis of the various disorders of purine and pyrimidine metabolism (more than 30
enzyme deficiencies have been described although only 17 are known to cause disease) is based on the
clinical presentation of the patient, determination of specific concentration patterns of purine and
pyrimidine metabolites, followed by confirmatory enzyme assays and/or molecular genetic testing.
Useful For: Evaluating patients with symptoms suspicious for disorders of purine and pyrimidine
metabolism Monitoring patients with disorders of purine and pyrimidine metabolism Laboratory
evaluation of primary and secondary hyperuricemias
Interpretation: A positive test result could be due to a genetic or nongenetic condition. Additional
confirmatory testing would be required. Abnormal concentrations of measurable compounds will be
reported along with an interpretation. The interpretation of an abnormal metabolite pattern includes an
overview of the results and of their significance, a correlation to available clinical information, possible
differential diagnosis, recommendations for additional biochemical testing and confirmatory studies
(enzyme assay, molecular analysis), name, and phone number of contacts who may provide these studies
at the Mayo Clinic or elsewhere, and a phone number of the laboratory directors in case the referring
physician has additional questions.
Reference Values:
URACIL
0-2 years: < or =31 mmol/mol creatinine
3-5 years: < or =30 mmol/mol creatinine
6-11 years: < or =28 mmol/mol creatinine
12-17 years: < or =26 mmol/mol creatinine
> or =18 years: < or =35 mmol/mol creatinine
URIC ACID
0-2 years: < or =2,249 mmol/mol creatinine
3-5 years: < or =1,900 mmol/mol creatinine
6-11 years: < or =1,398 mmol/mol creatinine
12-17 years: < or =698 mmol/mol creatinine
> or =18 years: < or =669 mmol/mol creatinine
HYPOXANTHINE
0-2 years: