Simple method for the quantitative analysis of dihydropyrimidines and N-carbamyl-beta-amino acids in urine

1H-NMR Spectroscopy of Body Fluids: Inborn Errors of Purine and Pyrimidine Metabolism

Background: The diagnosis of inborn errors of purine and pyrimidine metabolism is often difficult. We examined the potential of 1H-NMR as a tool in evaluation of patients with these disorders.

Methods: We performed 1H-NMR spectroscopy on 500 and 600 MHz instruments with a standardized sample volume of 500 μL. We studied body fluids from 25 patients with nine inborn errors of purine and pyrimidine metabolism.

Results: Characteristic abnormalities could be demonstrated in the 1H-NMR spectra of urine samples of all patients with diseases in the pyrimidine metabolism. In most urine samples from patients with defects in the purine metabolism, the 1H-NMR spectrum pointed to the specific diagnosis in a straightforward manner. The only exception was a urine from a case of adenine phosphoribosyl transferase deficiency in which the accumulating metabolite, 2,8-dihydroxyadenine, was not seen under the operating conditions used. Similarly, uric acid was not measured. We provide the 1H-NMR spectral characteristics of many intermediates in purine and pyrimidine metabolism that may be relevant for future studies in this field.

Conclusion: The overview of metabolism that is provided by 1H-NMR spectroscopy makes the technique a valuable screening tool in the detection of inborn errors of purine and pyrimidine metabolism.