Rare disease: a focus on metabolomics

Introduction: A disease or disorder is defined rare when it affects less than 1 in 2000 subjects. 400 million people worldwide are living with a rare disease; approximately 50% of these patients are children, and 30% of them die within the first 5 years of life. The wide aetiology diversity leads to high variability in symptomatology, and clinical manifestations and consequently to challenging diagnosis. New experimental approaches are therefore recommended to improve diagnosis, and for the development of new therapeutic strategies. In the last years, metabolomics have allowed to better understand the metabolic processes associated with several rare diseases. Areas covered: This review describes the use of metabolomics for the study of the metabolic alterations related to some of the most studied pediatric rare disorders. Metabolomics, by means of 1H NMR spectroscopy and MS spectrometry, allows the identification and the quantification of a large number of metabolites (biomarkers) in different biofluids. Expert opinion: Metabolomics proved to be a powerful tool for the clinical investigation of rare diseases. The power of discrimination seems to be reliable for all the considered biofluids (urine, blood, and amniotic fluid). Standardization of the analytical and statistical steps is still needed for further studies with larger populations and meta-analysis.