Of the 122 participants with FD who were screened from the community or who were outpatients, 23 declined to participate, 15 did not meet the inclusion and exclusion criteria (H. pylori positive, n = 9; significantly abnormal gastrin, n = 1; severe diabetes, n = 2; liver and kidney dysfunction, n = 1; antidepressant treatment, n = 1; and pregnancy, n = 1), and 4 refused to draw blood. Here, GAST is linked to Fabry disease.