There is no known cause of IC. I have ulcers in my bladder which effects my IC, so I think that it is some kind of autoimmune condition or other genetic condition that is eroding the protective lining and not only causing the
'I'm full so gotta go' signals to misfire but also causing the bladder to scar. However, for those with no ulcers, I think that it is only the misfiring of information between the bladder and the brain.