A missense variant in confers risk for Crohn's disease by disrupting manganese homeostasis and intestinal barrier integrity.

Common genetic variants interact with environmental factors to impact risk of heritable diseases. A notable example of this is a single-nucleotide variant in the Solute Carrier Family 39 Member 8 () gene encoding the missense variant A391T, which is associated with a variety of traits ranging from Parkinson's disease and neuropsychiatric disease to cardiovascular and metabolic diseases and Crohn's disease. The remarkable extent of pleiotropy exhibited by A391T raises key questions regarding how a single coding variant can contribute to this diversity of clinical outcomes and what is the mechanistic basis for this pleiotropy. Here, we generate a murine model for the A391T allele and demonstrate that these mice exhibit Mn deficiency in the colon associated with impaired intestinal barrier function and epithelial glycocalyx disruption. Consequently, A391T mice exhibit increased sensitivity to epithelial injury and pathological inflammation in the colon. Taken together, our results link a genetic variant with a dietary trace element to shed light on a tissue-specific mechanism of disease risk based on impaired intestinal barrier integrity.