The incidence in pediatrics is very low (about 0.5 per million according to a French study) and therefore the data on the pathology very poor, especially on the therapeutic level.

Without appropriate treatment, the mortality rate of the pathology is very high.

Existing treatments are almost exclusively composed of immunomodulatory and/or immunosuppressive treatments.

Complications related to pathology and iatrogeny are among the first causes of mortality from this pathology and deserve to be studied in order to be known and if possible avoided. The purpose of the study is to achieve a national comparison of clinical and therapeutic practices.

Inclusion criteria:

• Minor subject (<18 years old)
• Diagnosis of ANCA vasculitis according to the international criteria for defining the pathology, GPA or MPA form between 2011 and 2020.
• Subject (and/or his parental authority) who has not expressed, after being informed, his opposition to the reuse of his data for the purposes of this research.

Exclusion criteria:

• Subject (or his parents) having expressed his (their) opposition to participating in the study
• Patients with vasculitis has ANCA in the form of EGPA
• Associated pathologies that cannot be related to the diagnosis of ANCA vasculitis and whose prognosis can lead to biases in the efficacy and/or complications related to treatments.

Minor subject (<18 years old) with diagnosis of ANCA vasculitis according to the international criteria for defining the pathology, GPA or MPA form between 2011 and 2020.