Genome-wide association study identifies multiple HLA loci for sarcoidosis susceptibility

Area of Science:

• Genetics
• Immunology
• Systemic Diseases

Background:

• Sarcoidosis is a complex systemic inflammatory disease with an unknown etiology.
• Genetic factors, particularly those within the Human Leukocyte Antigen (HLA) complex, are implicated in sarcoidosis susceptibility.

Purpose of the Study:

• To identify novel alleles associated with sarcoidosis susceptibility.
• To evaluate the role of HLA alleles in sarcoidosis.
• To integrate genetic and transcription data to pinpoint risk loci impacting disease pathogenesis.

Main Methods:

• Genome-wide association study (GWAS) in European American (EA) and African American (AA) cohorts.
• Imputation and association testing of HLA alleles.
• Expression quantitative trait locus (eQTL) and colocalization analysis using transcriptome data.

Main Results:

• Forty-nine Single Nucleotide Polymorphisms (SNPs) in the HLA region (including HLA-DRA, -DRB9, -DRB5, -DQA1, and BRD2 genes) were associated with sarcoidosis in EA.
• The SNP rs3129888 was a risk variant in both EA and AA populations.
• Specific classical HLA alleles (DRB1*0101, DQA1*0101, DQB1*0501) were significantly associated with sarcoidosis.
• rs3135287 near HLA-DRA was linked to HLA-DRA expression.
• Six novel SNPs and nine HLA alleles associated with sarcoidosis susceptibility were identified.

Conclusions:

• The study identified novel genetic associations with sarcoidosis susceptibility in diverse populations.
• Findings reinforce the critical role of HLA class II genes in sarcoidosis pathogenesis, likely through antigen recognition and presentation pathways.