A proton nuclear magnetic resonance (1H-NMR) spectrometric method can be used to measure many compounds of purine and pyrimidine metabolism (13), but it has a major disadvantage in that it fails to detect uric acid and 2,8-dihydroxyadenine, which are very useful markers for the diagnosis of APRT deficiency, XDH deficiency, molybdenum cofactor deficiency, PRPPS super-activity, and
HGPRT deficiency. Capillary electrophoresis can also be used to measure many analytes, but it requires time-consuming sample preparation (14).
In the patients that used medication, the excretion was higher (xanthine, 312-827 [micro]mol/mmol creatinine; hypoxanthine, 855-1363 [micro]mol/mmol creatinine) because feedback inhibition of de novo purine synthesis by IMP and GMP does not take place because of the
HGPRT deficiency. Guanine was not detectable, whereas orotidine was clearly increased in both samples (112 and 63 [micro]mol/mmol creatinine).