LAUSR

Background Peptic ulcer is a common yet serious disease affected about 4 million people worldwide. Depression is considered a risk factor for peptic ulcer and may modify the etiology underlying peptic ulcer. Genetic factors contribute on the risk of developing peptic ulcer, but it remains unclear whether the genetic influences differ between depressed and non-depressed groups. In this study, we conducted genome-wide association studies for peptic ulcer stratified by depression status in Taiwanese samples. Methods Subjects in this study were drawn from Taiwan biobank with detailed demographic and clinical data collection. A total of 10,295 individuals were initially included, and 9,862 participants were retained after quality control, which consisted of 1,218 (12%) depression individuals based on prior diagnosis of major depressive disorder or high scores of self-report patient health questionnaire for depression and anxiety (scores greater than 3). Genetic association analyses were performed using logistic regression models while adjusted for age and sex. A p-value less than 10-5 was considered with suggestive association signals. Results Within depressed group, the top three associated SNPs were rs4775785 (P-value=1.20×10-7), rs10162880 (P=4.38×10-7) and rs7177833 (P=5.17×10-7). After gene mapping, these top SNPs were all map to the SHC4 gene, a protein coding gene on chromosome 15. In the non-depressed group, a different set of associated SNPs were observed, with rs11238817 (P=2.16×10-6) and rs11637781(P=4.41×10-6) showing suggestive signals without mapped to known coding genes. Discussion There is no overlapping markers or genes for peptic ulcer between the depressed and non-depressed groups, indicating different genetic profiles among the two groups. A replication study is needed with larger sample size, especially for the identified gene located on chromosome 15 in depressed individuals.