Although the number of PR3 positive patients was small, this study found a higher frequency of pulmonary and renal disease in PR3 positive cases than in MPO+ cases, and that leptomeningeal and parenchymal involvement in the brain were more common in PR3 positive hypertrophic pachymeningitis compared with MPO positive and idiopathic hypertrophic pachymeningitis. This evidence concerns the gene MPO and kidney disorder.