We simultaneously investigated the genetic landscape of ankylosing spondylitis, Crohn's disease, psoriasis, primary sclerosing cholangitis and ulcerative colitis to investigate pleiotropy and the relationship between these clinically related diseases. Using high-density genotype data from more than 86,000 individuals of European ancestry, we identified 244 independent multidisease signals, including 27 new genome-wide significant susceptibility loci and 3 unreported shared risk loci. Complex pleiotropy was supported when contrasting multidisease signals with expression data sets from human, rat and mouse together with epigenetic and expressed enhancer profiles. The comorbidities among the five immune diseases were best explained by biological pleiotropy rather than heterogeneity (a subgroup of cases genetically identical to those with another disease, possibly owing to diagnostic misclassification, molecular subtypes or excessive comorbidity). In particular, the strong comorbidity between primary sclerosing cholangitis and inflammatory bowel disease is likely the result of a unique disease, which is genetically distinct from classical inflammatory bowel disease phenotypes.

Original publication

DOI

10.1038/ng.3528

Type

Journal article

Journal

Nat Genet

Publication Date

05/2016

Volume

48

Pages

510 - 518

Keywords

Bayes Theorem, Cholangitis, Sclerosing, Chronic Disease, Colitis, Ulcerative, Comorbidity, Crohn Disease, Genetic Heterogeneity, Genetic Pleiotropy, Genetic Variation, Genome-Wide Association Study, Genotype, Humans, Inflammation, Psoriasis, Quantitative Trait Loci, Spondylitis, Ankylosing