Rare primary vasculitis: update on multiple complex diseases and the new kids on the block.

Systemic vasculitis is a group of rare diseases that share an essential characteristic: inflammation of blood vessel walls. This injury occurs during the disease course, but specific features vary for each entity. In this paper, we will address relevant aspects of the newest monogenic mutation vasculitis, such as deficiency of adenosine deaminase 2 (ADA2) and VEXAS syndrome (UBA1), and other relevant vasculitis, such as Cogan syndrome and Susac syndrome that may share some similarities with them.