Metabolomics: unraveling the chemical individuality of common human diseases.

Sir Archibald Garrod is often referred to in recent perspectives on metabolomics because he was the first to recognize 'inborn errors of metabolism'. For decades, the determination of metabolites was the domain of those involved in the diagnosis of this class of inherited disorders. With the development of metabolomics, these methods to determine and analyze metabolites have been taken an exciting step forward and are now used to understand common human disease. This concept of looking at metabolites to solve the pathogenesis of human disease touches upon another concept developed by Garrod, known as 'chemical individuality'. Garrod proposed that each person is biochemically unique due to inherited differences in enzymes, which is reflected in disease predisposition. In a more contemporary perspective, this concept may be extended to chemical individuality of a human disease. This is the domain of metabolomics, which aims to determine as many metabolites as possible in samples from a cohort of individuals. Analysis of the results will identify changes in metabolites that correlate with the presence of certain afflictions. The next challenging step is then to determine whether these metabolites are only biomarkers for the presence of a disease or new leads to an unknown etiology.