 In fact, this linkage on chromosome 6 may be the most convincing and consistent of the genetic candidates.Multiple autoimmune disorders have been recorded with the neurovisceral and cutaneous genetic porphyrias including UC, Crohn's disease, celiac disease, dermatitis herpetiformis, diabetes, systemic and discoid lupus, rheumatoid arthritis, ankylosing spondylitis, scleroderma, Sjögren syndrome and scleritis.Many hypotheses have been raised for environmental factors contributing to the pathogenesis of ulcerative colitis, including diet, breastfeeding and medications.