Automatic detection of roles of genetic markers in Crohn's disease by linear combinations of SNPs

polymorphisms; Motivations: A large number of single nucleotide polymorphisms (SNPs) are supposed to be involved in onset, differentiation and development of complex diseases. Univariate analysis is limited in studying complex traits since does not take into account gene—gene interaction, and the correlation of multiple SNPs with a specific phenotype. Moreover it might underestimate gene variants with weaker genetic contribution. Therefore more sophisticated techniques should be adopted when investigating the role of a panel of genetic markers in disease predisposition. Methods: In this paper we describe a general method to simultaneously investigate the association between SNPs profile and Crohn’s disease (CD), by evaluating the susceptibility or protective role of single or groups of markers. As an association measure we adopted a weighted linear combination of SNPs in which suitable weighting vectors belonged to predefined and over-complete vocabularies of vectors (frames), or were determined by the data.