Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

ObjectivesSystemic lupus erythematosus (SLE) is a chronic multisystem genetically complex autoimmune disease characterised by the production of autoantibodies to nuclear and cellular antigens, tissue inflammation and organ damage. Genome-wide association studies have shown that variants within the major histocompatibility complex (MHC) region on chromosome 6 confer the greatest genetic risk for SLE in European and Chinese populations. However, the causal variants remain elusive due to tight linkage disequilibrium across disease-associated MHC haplotypes, the highly polymorphic nature of many MHC genes and the heterogeneity of the SLE phenotype.MethodsA high-density case-control single nucleotide polymorphism (SNP) study of the MHC region was undertaken in SLE cohorts of Spanish and Filipino ancestry using a custom Illumina chip in order to fine-map association signals in these haplotypically diverse populations. In addition, comparative analyses were performed between these two datasets and a northern European UK SLE cohort. A total of 1433 cases and 1458 matched controls were examined.ResultsUsing this transancestral SNP mapping approach, novel independent loci were identified within the MHC region in UK, Spanish and Filipino patients with SLE with some evidence of interaction. These loci include HLA-DPB1, HLA-G and MSH5 which are independent of each other and HLA-DRB1 alleles. Furthermore, the established SLE-associated HLA-DRB1*15 signal was refined to an interval encompassing HLA-DRB1 and HLA-DQA1. Increased frequencies of MHC region risk alleles and haplotypes were found in the Filipino population compared with Europeans, suggesting that the greater disease burden in non-European SLE may be due in part to this phenomenon.ConclusionThese data highlight the usefulness of mapping disease susceptibility loci using a transancestral approach, particularly in a region as complex as the MHC, and offer a springboard for further fine-mapping, resequencing and transcriptomic analysis.

Original publication

DOI

10.1136/annrheumdis-2011-200808

Type

Journal article

Journal

Annals of the rheumatic diseases

Publication Date

05/2012

Volume

71

Pages

777 - 784

Addresses

Division of Genetics and Molecular Medicine and Division of Immunology, Infection and Inflammatory Disease, King's College London, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK. michelle.fernando@kcl.ac.uk

Keywords

IMAGEN, Humans, Lupus Erythematosus, Systemic, Genetic Predisposition to Disease, Cell Cycle Proteins, Genetic Markers, Case-Control Studies, Cohort Studies, Chromosome Mapping, Major Histocompatibility Complex, Polymorphism, Single Nucleotide, Ethnic Groups, Philippines, Spain, HLA-G Antigens, HLA-DP beta-Chains