Eileen Steinle Alexander, Ph.D.
University of Cincinnati
NIEHS Grants T32ES010957, P30ES006096
Researchers have found that the environment plays more of a role than genetics in eosinophilic esophagitis, a severe, chronic allergic inflammatory disease that renders people unable to eat a wide variety of foods. A better understanding of the risk factors for this disease could lead to better strategies for prevention and management and possibly identify modifiable environmental risk factors.
Although evidence suggests that eosinophilic esophagitis involves both genetic and environmental factors, scientists did not know the extent to which each contributes. To study gene and environment contributions, the researchers used a cohort of families at the Cincinnati Center for Eosinophilic Disorders at Cincinnati Children’s Hospital Medical Center. They also established a new separate cohort with histologically confirmed eosinophilic esophagitis in at least one twin or triplet.
The researchers found that 2.4 percent of siblings and 1.8 percent of first-degree relatives of patients with eosinophilic esophagitis also had the disease. Brothers, fathers, and males were more likely to have eosinophilic esophagitis than sisters, mothers, or females. Twins had 20 to 40 percent increased risk of eosinophilic esophagitis, depending upon whether they were identical or fraternal. Both the family and twin analyses supported a genetic contribution to eosinophilic esophagitis risk. Analysis of the twin cohort revealed genetic heritability contributed 14.5 percent of the variability while environmental factors were responsible for 81 percent. These findings show that much of the familial clustering seen with this disease is due to a shared environment.
Citation: Alexander ES, Martin LJ, Collins MH, Kottyan LC, Sucharew H, He H, Mukkada VA, Succop PA, Abonia JP, Foote H, Eby MD, Grotjan TM, Greenler AJ, Dellon ES, Demain JG, Furuta GT, Gurian LE, Harley JB, Hopp RJ, Kagalwalla A, Kaul A, Nadeau KC, Noel RJ, Putnam PE, von Tiehl KF, Rothenberg ME. 2014. Twin and family studies reveal strong environmental and weaker genetic cues explaining heritability of eosinophilic esophagitis. J Allergy Clin Immunol; doi: 10.1016/j.jaci.2014.07.021 [Online 22 September 2014].