The PedVas study is linked to an adult vasculitis initiative called DCVAS: Diagnosis and Classification Criteria in Vasculitis. Our DCVAS co-investigators and collaborators will recruit up to 250 adults at or near the time of diagnosis of the following forms of vasculitis: GPA, MPA, EGPA, TA, and UCV. Clinical data will be collected as part of the DCVAS study; this includes information such as laboratory test results, disease activity, and clinical history. Blood will also be collected and analyzed in parallel with samples collected from children with vasculitis. Finally, a DNA-biobank will be created and will house samples from approximately 700 adults and representing all forms of vasculitis. Recruitment will proceed according to DCVAS approved protocols and it will be conducted at participating DCVAS centres after the patient has formally consented to participation in the DCVAS study.