Consensus opinion at our centre, based on historical series and experience of delayed referral, is that these patients are at significant risk of progression to fulminant RPGN or, alternatively, more indolent renal disease that may result in progressive glomerulosclerosis, interstitial fibrosis and tubular atrophy, particularly in patients who are anti-MPO antibody positive [22]. This evidence concerns the gene MPO and rapidly progressive glomerulonephritis.