Mutant Adenosine Deaminase 2 in a Polyarteritis Nodosa Vasculopathy

Adenosine deaminase 2 (ADA2) is a protein with at least two functions. It is a growth factor affecting leukocytes and endothelial cells and an enzyme that influences purine metabolism. This study shows that mutant ADA2 causes polyarteritis nodosa. Polyarteritis nodosa, first described in 1866, 1 is a systemic necrotizing vasculitis that affects medium and small muscular arteries. 2 , 3 The ensuing tissue ischemia can affect any organ, including the skin, musculoskeletal system, kidneys, gastrointestinal tract, and the cardiovascular and nervous systems. Polyarteritis nodosa is usually diagnosed in middle age or later but can appear in childhood. 2 , 4 , 5 The diagnosis remains challenging despite classification criteria for adults 6 and children, 7 because polyarteritis nodosa frequently presents with nonspecific constitutional symptoms, and organ involvement and disease severity are highly varied. Polyarteritis nodosa is most often primary, but in adults it may be associated . . .