Since the early 1900s, it was postulated that a qualitative condition such as the presence/absence of a given pathology could be caused by multiple quantitative traits, each of which is influenced by a number of genetic variants.108 This model fits particularly well into the context of complex traits and common diseases in which many variants with small effect are involved in disease predisposition.109 In this context, the study of quantitative trait variation is a valuable approach to dissect the predisposition to complex diseases through the analysis of the biomedical parameters in population cohort individuals without the use of case-control strategies that rely on differences between patients vs healthy individuals. The dissection of quantitative trait variation in the general population shows several advantages including the large sample size and the collection of raw data unaffected by the pathology itself or by the drug treatment. This will increase the accuracy and robustness of data and thus will harness the power to detect associated variants in GWAS studies.
