HSP is a common small vessel vasculitis. It is the most common cause of non-thrombocytopenic purpura in childhood. The role of genes in etiopathogenesis of the disease, which has not yet been clearly elucidated, is being emphasized. Many genes called sialidases are being studied and is thought that the NEU1 gene may be particularly important in the etiopathogenesis of HSP. The aim of this study is to investigate the role of the NEU1 gene in the etiopathogenesis of HSP and its relation to renal involvement.