chronic inflammatory diseases
Chronic inflammatory diseases such as Crohn disease, atopic eczema, asthma and psoriasis are triggered by hitherto unknown environmental factors that function on the background of some polygenic susceptibility.
References
Schreiber S, Rosenstiel P, Albrecht M, Hampe J, Krawczak M. Genetics of Crohn disease, an archetypal inflammatory barrier disease. Nat Rev Genet. 2005 May;6(5):376-88. PMID: 15861209