there are even human leukocyte antigen associations which may be at work. 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 ulcerative colitis, Crohn's disease, celiac disease, dermatitis herpetiformis, diabetes, systemic and discoid lupus,