| Contributors: |
Asselta, R; Paraboschi, E; Gerussi, A; Cordell, H; Mells, G; Sandford, R; Jones, D; Nakamura, M; Ueno, K; Hitomi, Y; Kawashima, M; Nishida, N; Tokunaga, K; Nagasaki, M; Tanaka, A; Tang, R; Li, Z; Shi, Y; Liu, X; Xiong, M; Hirschfield, G; Siminovitch, K; Walker, E; Xie, G; Mason, A; Myers, R; Peltekian, K; Ghent, C; Atkinson, E; Juran, B; Lazaridis, K; Lu, Y; Gu, X; Jing, K; Amos, C; Affronti, A; Brunetto, M; Coco, B; Spinzi, G; Elia, G; Ferrari, C; Lleo, A; Muratori, L; Muratori, P; Portincasa, P; Colli, A; Bruno, S; Colloredo, G; Azzaroli, F; Andreone, P; Bragazzi, M; Alvaro, D; Cardinale, V; Cazzagon, N; Rigamonti, C; Floreani, A; Rosina, F; Ciaccio, A; Cristoferi, L; D'Amato, D; Malinverno, F; Mancuso, C; Massironi, S; Milani, C; O'Donnell, S; Ronca, V; Barisani, D; Lampertico, P; Donato, F; Fagiuoli, S; Almasio, P; Giannini, E; Cursaro, C; Colombo, M; Valenti, L; Miele, L; Andriulli, A; Niro, G; Grattagliano, I; Morini, L; Casella, G; Vinci, M; Battezzati, P; Crosignani, A; Zuin, M; Mattalia, A; Calvaruso, V; Colombo, S; Benedetti, A; Marzioni, M; Galli, A; Marra, F; Tarocchi, M; Picciotto, A; Morisco, F; Fabris, L; Croce, L; Tiribelli, C; Toniutto, P; Strazzabosco, M |
| Description: |
Background & Aims: Genome-wide association studies in primary biliary cholangitis (PBC) have failed to find X chromosome (chrX) variants associated with the disease. Here, we specifically explore the chrX contribution to PBC, a sexually dimorphic complex autoimmune disease. Methods: We performed a chrX-wide association study, including genotype data from 5 genome-wide association studies (from Italy, United Kingdom, Canada, China, and Japan; 5244 case patients and 11,875 control individuals). Results: Single-marker association analyses found approximately 100 loci displaying P < 5 × 10–4, with the most significant being a signal within the OTUD5 gene (rs3027490; P = 4.80 × 10–6; odds ratio [OR], 1.39; 95% confidence interval [CI], 1.028–1.88; Japanese cohort). Although the transethnic meta-analysis evidenced only a suggestive signal (rs2239452, mapping within the PIM2 gene; OR, 1.17; 95% CI, 1.09–1.26; P = 9.93 × 10–8), the population-specific meta-analysis showed a genome-wide significant locus in East Asian individuals pointing to the same region (rs7059064, mapping within the GRIPAP1 gene; P = 6.2 × 10–9; OR, 1.33; 95% CI, 1.21–1.46). Indeed, rs7059064 tags a unique linkage disequilibrium block including 7 genes: TIMM17B, PQBP1, PIM2, SLC35A2, OTUD5, KCND1, and GRIPAP1, as well as a superenhancer (GH0XJ048933 within OTUD5) targeting all these genes. GH0XJ048933 is also predicted to target FOXP3, the main T-regulatory cell lineage specification factor. Consistently, OTUD5 and FOXP3 RNA levels were up-regulated in PBC case patients (1.75- and 1.64-fold, respectively). Conclusions: This work represents the first comprehensive study, to our knowledge, of the chrX contribution to the genetics of an autoimmune liver disease and shows a novel PBC-related genome-wide significant locus. |