HI all, 

You may be interested in this new research .. it suggests that genetic background is a causal factor in the development of UC and ankylosing spondylitis, Crohn's Disease, psoriasis, and primary sclerosing cholangitis. They studies 86,000 people, over 26 countries. 

https://www.sciencedaily.com/r.../03/160315104658.htm

"The discoveries have shed new light onto the causes of these diseases, such as identifying genetic risk variants which most likely work by affecting the bacteria present in the gut, in turn causing inflammation in joints, the liver or the gut itself," Professor Brown said.