179. SECONDARY VASCULITIS DUE TO SINGLE GENE DEFECTS

Background: In recent years we have become aware that auto inflammatory diseases associated with single gene defects may also present with vasculitis. In fact this group may be classified under the category of “others; those associated with single gene defects” among the secondary vasculitis of CHCC2012. We present our single center experience with these monogenic diseases. Methods: Diagnosed as (1) vascultides due to deficiency of ADA2 (DADA2) with polyarteritis nodosa like features and marked inflammatory attacks, (2) patients with vasculopathy and a confirmed interferonopathy and (3) patient with immunodeficiency were included. The median age at onset of symptoms was 42 (1-420) months. They were genetically tested because of a family history or typical features. In the case of DADA2, they were also tested if they had a history of early stroke or did not respond to conventional therapy. Results: 1. The first group was vasculitis mimicking PAN (DADA2): Serum ADA2 was low and the diagnosis was confirmed genetically in all of these 15 DADA2 patients. The skin manifestations were prominent in the majority of the patients. Microaneurysms in medium-sized arteries were shown in angiography in 6 (42.8%) (3 pediatric, 3 adult) patients. Necrotizing vasculitis involving small- to medium-sized arteries was demonstrated in biopsies in 5 (35.7%) patients.2. The second group was the auto inflammatory interferonopathies presenting with vasculopathy: In this group we present two pediatric patients: one with the classical phenotype of STING-associated vasculitis of infancy (SAVI) and one with CANDLE-like features, both had high interferon signatures. 3. The final group was the secondary vasculitides associated with a defined (monogenic) immunodeficiency. We present one typical patient with RAG1 deficiency who had severe pulmonary and skin vasculitis. The vasculitic features of auto inflammatory diseases may also be included in this group and will be shortly discussed. Conclusion: It is important to be aware of these monogenic diseases with vasculitic features, since the diagnostic delay may be considerable and the treatment differs than classical vasculitis. Disclosures: None