Genetics of vasculitis

Systemic vasculitis arises on a background of genetic predisposition shaped by HLA and non-HLA variations, triggered by environmental factors. This review summarizes recent genomic information translating molecular discoveries into clinical risk stratification.

In large vessel vasculitis group, giant cell arteritis is associated with MHC class II, especially HLA-DRB1*04 alleles. Somatic TET2 mutations increase the risk of GCA-associated vision loss. Association of some genetic variants with different subgroups of GCA was also reported. On the other hand, Takayasu arteritis is associated with MHC class I region, predominantly HLA-B*52, predicting aggressive vascular remodeling and the need for early surgical intervention. In medium-vessel vasculitis group, specific genetic factors, associated with polyarteritis nodosa (PAN) could not be shown. However, recessive CECR1 (ADA2) mutations define a monogenic mimic of PAN, known as DADA2, that manifests as early-onset strokes. In Kawasaki disease, a complex polygenic model exists involving HLA-DRB1*15:01 for susceptibility and HLA-DRB1*14:01 for coronary lesions. ANCA-associated vasculitis (AAV) better correlates with autoantibody status rather than with clinical phenotypes. PR3-ANCA exhibits a strong association with HLA-DPB1*0401 and SERPINA1 variants, predicting chronic relapses. MPO-ANCA is linked to HLA-DQ loci, predisposing patients to rapidly progressing glomerulonephritis. Association of certain HLA susceptibility markers with different subgroups of AAV was also reported. Finally, Behçet's syndrome exhibits strong epistatic interactions with HLA-B*51 and ERAP1.

Genomic mapping reveals not only associations of specific genetic variations with different vasculitis but also their effects to determine clinical subgroups, ischemic risk, and clinical outcomes.