In 12 (40%) of them it was preceded by: arthritis, in 6 (20%) by gastrointestinal complaints, in 5 (17%) hematuria in 1 (3%). Histological examination of the skin biopsies revealed typical leukocytoclastic vasculitis in all patients; whereas immunofluorescence studies showed perivascular IgA deposition in 28 (93.3%), C3 deposition in 13(43.3%) and IgM deposition in 5 (16.6%) patients. This evidence concerns the gene C3 and Arthritis.