Monozygotic twins with Crohn's disease: a case report.

Twin brothers whose monozygosity was demonstrated by analysis of dermatoglyphic patterns, chromosome banding, HLA typing, and gene markers developed Crohn's disease within 8 mo of each other. Both had involvement of the terminal ileum, colon, and rectum, as well as arthritis. However, one had severe esophagitis and recurrent pancreatitis, and the other had severe arthritis and oral mucosal involvement. Both twins had manifestations controlled by parenteral nutrition. This report describes the similarities and differences in the complicated course of Crohn's disease in identical twins and demonstrates that while the development of Crohn's disease may be genetically influenced the site of gastrointestinal involvement is affected by other factors. This experience does not support previously held concepts of the role of genetics in the clinical manifestations of Crohn's disease.