Common ground: shared risk factors for type 1 diabetes and celiac disease.

Risk factors for most autoimmune diseases are multifactorial genetic variants modified by environmental risk factors. Type 1 diabetes and celiac disease share high-risk HLA haplotypes, and the prevalence of both diseases has increased in many regions during the past half century. Unknown environmental factors are suspected to have increased the disease penetrance. Celiac disease depends on immune responses to dietary gluten, whereas the environmental risk factors for type 1 diabetes are not yet clear. Here, we consider the shared heritable genetic factors and review evidence of the dietary and microbial exposures, particularly in early life, that might influence the pathogenesis of one or both diseases. A deeper mechanistic understanding of the environmental factors responsible for increased risk of these diseases should provide opportunities to manipulate exposure in children carrying defined risk markers and thus prevent and attenuate disease, as well as to identify new therapeutic strategies for patients.