The Central Role of <i>KNG1</i> Gene as a Genetic Determinant of Coagulation Pathway-Related Traits: Exploring <i>Metaphenotypes</i>

<div><p>Traditional genetic studies of single traits may be unable to detect the pleiotropic effects involved in complex diseases. To detect the correlation that exists between several phenotypes involved in the same biological process, we introduce an original methodology to analyze sets of correlated phenotypes involved in the coagulation cascade in genome-wide association studies. The methodology consists of a two-stage process. First, we define new phenotypic meta-variables (linear combinations of the original phenotypes), named <i>metaphenotypes</i>, by applying Independent Component Analysis for the multivariate analysis of correlated phenotypes (i.e. the levels of coagulation pathway–related proteins). The resulting <i>metaphenotypes</i> integrate the information regarding the underlying biological process (i.e. thrombus/clot formation). Secondly, we take advantage of a family based Genome Wide Association Study to identify genetic elements influencing these <i>metaphenotypes</i> and consequently thrombosis risk. Our study utilized data from the GAIT Project (Genetic Analysis of Idiopathic Thrombophilia). We obtained 15 <i>metaphenotypes</i>, which showed significant heritabilities, ranging from 0.2 to 0.7. These results indicate the importance of genetic factors in the variability of these traits. We found 4 <i>metaphenotypes</i> that showed significant associations with SNPs. The most relevant were those mapped in a region near the <i>HRG</i>, <i>FETUB</i> and <i>KNG1</i> genes. Our results are provocative since they show that the <i>KNG1</i> locus plays a central role as a genetic determinant of the entire coagulation pathway and thrombus/clot formation. Integrating data from multiple correlated measurements through <i>metaphenotypes</i> is a promising approach to elucidate the hidden genetic mechanisms underlying complex diseases.</p>