Carroll MC. The lupus paradox. Nat Genet. 1998;19:3–4. https://doi.org/10.1038/ng0598-3.

Article  CAS  PubMed  Google Scholar 

Lood C, Gullstrand B, Truedsson L, Olin AI, Alm GV, Rönnblom L, Sturfelt G, Eloranta M-L, Bengtsson AA. C1q inhibits immune complex-induced interferon-alpha production in plasmacytoid dendritic cells: a novel link between C1q deficiency and systemic lupus erythematosus pathogenesis. Arthritis Rheum. 2009;60:3081–90. https://doi.org/10.1002/art.24852.

Article  CAS  PubMed  Google Scholar 

Barilla-LaBarca M-L, Atkinson JP. Rheumatic syndromes associated with complement deficiency. Curr Opin Rheumatol. 2003;15:55–60. https://doi.org/10.1097/00002281-200301000-00010.

Article  CAS  PubMed  Google Scholar 

Walport MJ. Complement and systemic lupus erythematosus. Arthritis Res 4 Suppl. 2002;3S279–293. https://doi.org/10.1186/ar586.

Pickering MC, Botto M, Taylor PR, Lachmann PJ, Walport MJ. Systemic lupus erythematosus, complement deficiency, and apoptosis. Adv Immunol. 2000;76:227–324. https://doi.org/10.1016/s0065-2776(01)76021-x.

Article  CAS  PubMed  Google Scholar 

Truedsson L, Bengtsson AA, Sturfelt G. Complement deficiencies and systemic lupus erythematosus. Autoimmunity. 2007;40:560–6. https://doi.org/10.1080/08916930701510673.

Article  CAS  PubMed  Google Scholar 

Chu X, Rittner C, Schneider PM. Length polymorphism of the human complement component C4 gene is due to an ancient retroviral integration. Exp Clin Immunogenet. 1995;12:74–81.

CAS  PubMed  Google Scholar 

Dangel AW, Mendoza AR, Baker BJ, Daniel CM, Carroll MC, Wu LC, Yu CY. The dichotomous size variation of human complement C4 genes is mediated by a novel family of endogenous retroviruses, which also establishes species-specific genomic patterns among Old World primates. Immunogenetics. 1994;40:425–36. https://doi.org/10.1007/BF00177825.

Article  CAS  PubMed  Google Scholar 

Wu YL, Savelli SL, Yang Y, Zhou B, Rovin BH, Birmingham DJ, Nagaraja HN, Hebert LA, Yu CY. Sensitive and specific real-time polymerase chain reaction assays to accurately determine copy number variations (CNVs) of human complement C4A, C4B, C4-long, C4-short, and RCCX modules: elucidation of C4 CNVs in 50 consanguineous subjects with defined HLA genotypes. J Immunol. 2007;179:3012–25. https://doi.org/10.4049/jimmunol.179.5.3012.

Article  CAS  PubMed  Google Scholar 

Yang Z, Mendoza AR, Welch TR, Zipf WB, Yu CY. Modular variations of the human major histocompatibility complex class III genes for serine/threonine kinase RP, complement component C4, steroid 21-hydroxylase CYP21, and tenascin TNX (the RCCX module). A mechanism for gene deletions and disease associations. J Biol Chem. 1999;274:12147–56. https://doi.org/10.1074/jbc.274.17.12147.

Article  CAS  PubMed  Google Scholar 

Griffiths DJ. Endogenous retroviruses in the human genome sequence. Genome Biol. 2001;2:REVIEWS1017. https://doi.org/10.1186/gb-2001-2-6-reviews1017.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Blanchong CA, Zhou B, Rupert KL, Chung EK, Jones KN, Sotos JF, Zipf WB, Rennebohm RM, Yung C, Yu. Deficiencies of human complement component C4A and C4B and heterozygosity in length variants of RP-C4-CYP21-TNX (RCCX) modules in caucasians. The load of RCCX genetic diversity on major histocompatibility complex-associated disease. J Exp Med. 2000;191:2183–96. https://doi.org/10.1084/jem.191.12.2183.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Song R-H, Gao C-Q, Zhao J, Zhang J-A. An Update Evolving View of Copy Number variations in Autoimmune diseases. Front Genet. 2021;12:794348. https://doi.org/10.3389/fgene.2021.794348.

Article  CAS  PubMed  Google Scholar 

Yeo NK-W, Lim CK, Yaung KN, Khoo NKH, Arkachaisri T, Albani S, Yeo JG. Genetic interrogation for sequence and copy number variants in systemic lupus erythematosus. Front Genet. 2024;15:1341272. https://doi.org/10.3389/fgene.2024.1341272.

Article  PubMed  PubMed Central  Google Scholar 

Mamtani M, Rovin B, Brey R, Camargo JF, Kulkarni H, Herrera M, Correa P, Holliday S, Anaya J-M, Ahuja SK. CCL3L1 gene-containing segmental duplications and polymorphisms in CCR5 affect risk of systemic lupus erythaematosus. Ann Rheum Dis. 2008;67:1076–83. https://doi.org/10.1136/ard.2007.078048.

Article  CAS  PubMed  Google Scholar 

Molokhia M, Fanciulli M, Petretto E, Patrick AL, McKeigue P, Roberts AL, Vyse TJ, Aitman TJ. FCGR3B copy number variation is associated with systemic lupus erythematosus risk in afro-caribbeans. Rheumatology (Oxford). 2011;50:1206–10. https://doi.org/10.1093/rheumatology/keq456.

Article  CAS  PubMed  Google Scholar 

Chen J-Y, Wang C-M, Chang S-W, Cheng C-H, Wu Y-JJ, Lin J-C, Yang B, Ho H-H, Wu J. Association of FCGR3A and FCGR3B copy number variations with systemic lupus erythematosus and rheumatoid arthritis in Taiwanese patients. Arthritis Rheumatol. 2014;66:3113–21. https://doi.org/10.1002/art.38813.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Zhang M, Gu Y, Huang S, Lou Q, Xie Q, Xu Z, Chen Y, Pan F, Xu S, Liu S, Tao J, Liu S, Cai J, Chen P, Qian L, Wang C, Liang C, Huang H, Pan H, Su H, Cheng J, Zhang Y, Hu W, Zou Y. Copy number variations and polymorphisms in HSP90AB1 and risk of systemic lupus erythematosus and efficacy of glucocorticoids. J Cell Mol Med. 2019;23:5340–8. https://doi.org/10.1111/jcmm.14410.

Article  CAS  PubMed  PubMed Central  Google Scholar 

García-Ortiz H, Velázquez-Cruz R, Espinosa-Rosales F, Jiménez-Morales S, Baca V, Orozco L. Association of TLR7 copy number variation with susceptibility to childhood-onset systemic lupus erythematosus in Mexican population. Ann Rheum Dis. 2010;69:1861–5. https://doi.org/10.1136/ard.2009.124313.

Article  CAS  PubMed  Google Scholar 

Kim J-H, Jung S-H, Bae JS, Lee H-S, Yim S-H, Park S-Y, Bang S-Y, Hu H-J, Shin HD, Bae S-C, Chung Y-J. Deletion variants of RABGAP1L, 10q21.3, and C4 are associated with the risk of systemic lupus erythematosus in Korean women. Arthritis Rheum. 2013;65:1055–63. https://doi.org/10.1002/art.37854.

Article  CAS  PubMed  Google Scholar 

Yokoyama N, Kawasaki A, Matsushita T, Furukawa H, Kondo Y, Hirano F, Sada K-E, Matsumoto I, Kusaoi M, Amano H, Nagaoka S, Setoguchi K, Nagai T, Shimada K, Sugii S, Hashimoto A, Matsui T, Okamoto A, Chiba N, Suematsu E, Ohno S, Katayama M, Migita K, Kono H, Hasegawa M, Kobayashi S, Yamada H, Nagasaka K, Sugihara T, Yamagata K, Ozaki S, Tamura N, Takasaki Y, Hashimoto H, Makino H, Arimura Y, Harigai M, Sato S, Sumida T, Tohma S, Takehara K, Tsuchiya N. Association of NCF1 polymorphism with systemic lupus erythematosus and systemic sclerosis but not with ANCA-associated vasculitis in a Japanese population. Sci Rep. 2019;9:16366. https://doi.org/10.1038/s41598-019-52920-0.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Brunson T, Wang Q, Chambers I, Song Q. A copy number variation in human NCF1 and its pseudogenes. BMC Genet. 2010;11:13. https://doi.org/10.1186/1471-2156-11-13.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Linge P, Arve S, Olsson LM, Leonard D, Sjöwall C, Frodlund M, Gunnarsson I, Svenungsson E, Tydén H, Jönsen A, Kahn R, Johansson Å, Rönnblom L, Holmdahl R, Bengtsson A. NCF1-339 polymorphism is associated with altered formation of neutrophil extracellular traps, high serum interferon activity and antiphospholipid syndrome in systemic lupus erythematosus. Ann Rheum Dis. 2020;79:254–61. https://doi.org/10.1136/annrheumdis-2019-215820.

Article  CAS  PubMed  Google Scholar 

Yang Y, Chung EK, Wu YL, Savelli SL, Nagaraja HN, Zhou B, Hebert M, Jones KN, Shu Y, Kitzmiller K, Blanchong CA, McBride KL, Higgins GC, Rennebohm RM, Rice RR, Hackshaw KV, Roubey RAS, Grossman JM, Tsao BP, Birmingham DJ, Rovin BH, Hebert LA, Yu CY. Gene copy-number variation and associated polymorphisms of complement component C4 in human systemic lupus erythematosus (SLE): low copy number is a risk factor for and high copy number is a protective factor against SLE susceptibility in European americans. Am J Hum Genet. 2007;80:1037–54. https://doi.org/10.1086/518257.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Chen JY, Wu YL, Mok MY, Wu Y-JJ, Lintner KE, Wang C-M, Chung EK, Yang Y, Zhou B, Wang H, Yu D, Alhomosh A, Jones K, Spencer CH, Nagaraja HN, Lau YL, Lau C-S, Yu CY. Effects of Complement C4 Gene Copy Number variations, size dichotomy, and C4A Deficiency on genetic risk and clinical presentation of systemic lupus erythematosus in east Asian populations. Arthritis Rheumatol. 2016;68:1442–53. https://doi.org/10.1002/art.39589.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Yang Y, Chung EK, Zhou B, Blanchong CA, Yu CY, Füst G, Kovács M, Vatay A, Szalai C, Karádi I, Varga L. Diversity in intrinsic strengths of the human complement system: serum C4 protein concentrations correlate with C4 gene size and polygenic variations, hemolytic activities, and body mass index. J Immunol. 2003;171:2734–45. https://doi.org/10.4049/jimmunol.171.5.2734.

Article  CAS  PubMed  Google Scholar 

Mulvihill E, Ardoin S, Thompson SD, Zhou B, Yu GR, King E, Singer N, Levy DM, Brunner H, Wu YL, Nagaraja HN, Schanberg LE, Yu C-Y. Elevated serum complement levels and higher gene copy number of complement C4B are associated with hypertension and effective response to statin therapy in childhood-onset systemic lupus erythematosus (SLE). Lupus Sci Med. 2019;6:e000333. https://doi.org/10.1136/lupus-2019-000333.

Article  PubMed  PubMed Central  Google Scholar 

Pereira KMC, Faria AGA, Liphaus BL, Jesus AA, Silva CA, Carneiro-Sampaio M, Andrade LEC. Low C4, C4A and C4B gene copy numbers are stronger risk factors for juvenile-onset than for adult-onset systemic lupus erythematosus. Rheumatology. 2016;55:869–73. https://doi.org/10.1093/rheumatology/kev436.

Article  CAS  PubMed  Google Scholar 

Alperin JM, Ortiz-Fernández L, Sawalha AH. Monogenic lupus: a developing paradigm of Disease. Front Immunol. 2018;9:2496. https://doi.org/10.3389/fimmu.2018.02496.

Article  CAS  PubMed  PubMed Central