The deficiency of adenosine deaminase 2 (DADA2) was initially described as a syndrome of small and medium-sized vessel vasculitis/vasculopathy manifesting as recurrent episodes of fever, early-onset lacunar strokes, and cutaneous involvement including livedo racemosa, Raynaud’s phenomenon, and polyarteritis nodosa. Here, ADA2 is linked to polyarteritis nodosa.