REGIMEN STRIKES BACK. DIAGNOSIS, GENES AND THE PATIENT

The paper focuses on the conceptual innovations introduced by recent developments in genetics and genomics in diagnosis, both in its cognitive and clinical aspect. Genetic diagnosis started as the recognition of statistically significant occurrence of symptoms within families, and later became the simple test to diagnose a molecular disease, by highlighting the presence of a single pathological gene (or of a few of them). The advent of cheap genomic technologies allowed for genome-wide data collection, so that even complex traits, physiological as well as pathological, may be diagnosed. However, genome analysis has revealed that most phenotypic traits are the result of the interaction of multiple genes and of the environment. Diagnosis in the genomic age is no longer the act of connecting symptoms and the recognition of a pattern, but it crucially involves statistical concepts such as risk and contribution, leaving a wide space of uncertainty for therapeutic action. The lifestyle of the patient is back again at the center of the stage: in order to stave off disease, an individual regimen may be the best available option.