Discordance for childhood coeliac disease in monozygotic twins.

Discordance for childhood coeliac disease in monozygotic twin boys is reported. The diagnosis of coeliac disease in the second-born twin was established by demonstration of a flat small intestinal mucosa on biopsy and a clinical response to a gluten-free diet. The first-born twin had a normal small intestinal mucosa. Phenotypic, genotypic, and dermatoglyphic observations as well as gross observation of the placenta and membranes provided strong evidence that these twin boys were monozygotic.