Granulomatous autoinflammatory syndrome

Granulomatous autoinflammatory syndrome, also known as Blau syndrome or familial juvenile systemic granulomatosis, is a rare autoinflammatory disorder caused by mutations in the NOD2 (CARD15) gene. It is characterized by the clinical triad of granulomatous dermatitis, symmetric polyarthritis, and recurrent uveitis, typically presenting in early childhood. The condition is distinguished from sarcoidosis by its hereditary nature and earlier onset, though the two conditions share overlapping features including the formation of non-caseating granulomas in affected tissues. The disease primarily affects the skin, joints, and eyes. Skin manifestations often appear first, presenting as a tan-colored or reddish-brown papular rash with granulomatous inflammation on biopsy. Joint involvement typically manifests as boggy synovitis with granulomatous inflammation, which can lead to camptodactyly (permanent flexion contractures of the fingers) and significant functional impairment if untreated. Ocular disease, particularly chronic anterior uveitis, can be severe and may lead to vision loss including cataracts, glaucoma, and band keratopathy. Some patients may also develop granulomatous inflammation in other organs, including the kidneys, liver, and blood vessels (large-vessel vasculitis), as well as intermittent fevers and elevated inflammatory markers. There is no cure for granulomatous autoinflammatory syndrome. Treatment is aimed at controlling inflammation and preventing organ damage. Corticosteroids have traditionally been used, but long-term side effects limit their utility. Biologic therapies, particularly TNF-alpha inhibitors (such as infliximab and adalimumab) and IL-1 receptor antagonists (such as anakinra), have shown benefit in managing symptoms and reducing granulomatous inflammation. Regular ophthalmologic monitoring is essential to prevent irreversible vision loss. Early diagnosis and multidisciplinary management involving rheumatology, ophthalmology, and dermatology are critical for optimizing outcomes.

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