Birdshot Chorioretinopathy - Pathophysiology

Pathophysiology

Birdshot chorioretinopathy is a rare form of posterior uveitis and accounts for 1-3% of uveitis cases in general. Birdshot chorioretinopathy is thought to be an autoimmune disease. The disease has strong association with the Human leukocyte antigen haplotype (HLA)-A29, which is the strongest association between a disease and HLA class I documented (85 to 97.5% of patients are HLA-A29 positive). This indicates a role for T-lymphocytes in the pathogenesis. BSCR is associated with IL-17, a hallmark cytokine of T helper 17 cells that play an important role in autoimmunity . The disease affects typically middle aged or elderly, white caucasians. HLA-A29 is less prevalent in Asia and no birdshot chorioretinopathy cases have been reported in Asia. When birdshot chorioretinopathy is suspected, a person is usually tested to determine if they are HLA-A29 positive. However, HLA-A29 testing is not considered vital for definitive diagnosis. Since HLA-A29 is also common in the general healthy population (7%), additional (genetic or environmental) or unknown factors may be associated with HLA-A29 in the pathogenesis of BSCR.

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