Objective: The aim of this study was to investigate the role of genetic factors and the characteristics of five monozygous twin pairs with at least one member affected by gluten sensitivity.
Methods: Five pairs of monozygous female twins, of whom one or both were affected by gluten sensitivity (i.e., celiac disease or dermatitis herpetiformis), were followed-up for 11-23 yr.
Results: Three pairs were concordant for celiac disease: the onset was comparable and synchronous in two pairs; in the third, one member presented an overt malabsorption syndrome, and the other developed iron deficiency anemia 10 yr later. Discordance for gluten sensitivity was found in the remaining two pairs, one of whose members was diagnosed as having, respectively, celiac disease and dermatitis herpetiformis.
Conclusions: As no environmental factors were found to affect the phenotypic expression of the disease, genetic factors seem to play a major role. The presence of overt or latent celiac disease in three of the four siblings of the three concordant twins, and the association with cystic fibrosis in all three siblings of one of these families, further supports this hypothesis.