Using Urine NMR Spectroscopy in the Diagnosis of Intoxication-Type Inborn Errors of Metabolism

Background: Intoxication-type inborn errors of metabolism (i-IEM) are a group of genetic disorders which can be diagnosed through neonatal screening, NMR spectroscopy, and molecular genetic analyses.

Methods: We report twelve cases of i-IEM diagnosed by selective urine NMR spectroscopy considering there is no extended neonatal screening in the Republic of Moldova.

Results: There were 9 cases of methylmalonic aciduria (MMA), 2 cases of glutaric aciduria type 1 (GA1), and 1 case of OTC deficiency. In all cases diagnosed by NMR spectroscopy, they presented specific urinary metabolites as markers for this i-IEM. In all cases of MMA, a high level of methylmalonic acid in urine was identified by NMR spectroscopy. In two cases of GA1, there was determined glutaric and 3-hydroxy glutaric acids. Orotic acid was present in OTC deficiency and one case of MMA was preceded by severe ammonia episodes. All cases were confirmed by molecular genetic analyses.

Conclusion: Urine NMR spectroscopy can be used as a tool in the diagnosis of i-IEM in the case of no neonatal screening programmes.