Genome‐Wide Association Analysis Reveals Genetic Heterogeneity of Sjögren's Syndrome According to Ancestry

• Published in: Arthritis & rheumatology (Hoboken, N.J.) Vol. 69; no. 6; pp. 1294 - 1305
• Main Authors: Taylor, Kimberly E., Wong, Quenna, Levine, David M., McHugh, Caitlin, Laurie, Cathy, Doheny, Kimberly, Lam, Mi Y., Baer, Alan N., Challacombe, Stephen, Lanfranchi, Hector, Schiødt, Morten, Srinivasan, M., Umehara, Hisanori, Vivino, Frederick B., Zhao, Yan, Shiboski, Stephen C., Daniels, Troy E., Greenspan, John S., Shiboski, Caroline H., Criswell, Lindsey A.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.06.2017; John Wiley and Sons Inc
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Asian People - genetics; Association analysis; Autoantibodies - genetics; Case-Control Studies; Etiology; Female; Gene Frequency; Genetic Heterogeneity; Genetic Predisposition to Disease; Genome-wide association studies; Genome-Wide Association Study; Genomes; Genotype; Genotyping; Heterogeneity; Humans; Interferon Regulatory Factors - genetics; KLRG1 protein; Lectins, C-Type - genetics; Major Histocompatibility Complex; Male; Minority & ethnic groups; Phenotype; Phenotyping; Polymorphism, Single Nucleotide; Population genetics; Population studies; Receptors, Immunologic; Registries; Salivary gland; Salivary Glands, Minor; Single-nucleotide polymorphism; Sjogren's syndrome; Sjogren's Syndrome - genetics; Sjöogren's Syndrome; Stat4 protein; STAT4 Transcription Factor - genetics; Trans-Activators - genetics; White People - genetics
• ISSN: 2326-5191; 2326-5205; 2326-5205
• DOI: 10.1002/art.40040

Objective The Sjögren's International Collaborative Clinical Alliance (SICCA) is an international data registry and biorepository derived from a multisite observational study of participants in whom genotyping was performed on the Omni2.5M platform and who had undergone deep phenotyping using common protocol‐directed methods. The aim of this study was to examine the genetic etiology of Sjögren's syndrome (SS) across ancestry and disease subsets. Methods We performed genome‐wide association study analyses using SICCA subjects and external controls obtained from dbGaP data sets, one using all participants (1,405 cases, 1,622 SICCA controls, and 3,125 external controls), one using European participants (585, 966, and 580, respectively), and one using Asian participants (460, 224, and 901, respectively) with ancestry adjustments via principal components analyses. We also investigated whether subphenotype distributions differ by ethnicity, and whether this contributes to the heterogeneity of genetic associations. Results We observed significant associations in established regions of the major histocompatibility complex (MHC), IRF5, and STAT4 (P = 3 × 10−42, P = 3 × 10−14, and P = 9 × 10−10, respectively), and several novel suggestive regions (those with 2 or more associations at P < 1 × 10−5). Two regions have been previously implicated in autoimmune disease: KLRG1 (P = 6 × 10−7 [Asian cluster]) and SH2D2A (P = 2 × 10−6 [all participants]). We observed striking differences between the associations in Europeans and Asians, with high heterogeneity especially in the MHC; representative single‐nucleotide polymorphisms from established and suggestive regions had highly significant differences in the allele frequencies in the study populations. We showed that SSA/SSB autoantibody production and the labial salivary gland focus score criteria were associated with the first worldwide principal component, indicative of higher non‐European ancestry (P = 4 × 10−15 and P = 4 × 10−5, respectively), but that subphenotype differences did not explain most of the ancestry differences in genetic associations. Conclusion Genetic associations with SS differ markedly according to ancestry; however, this is not explained by differences in subphenotypes.