Studies have found, for example, that ELISA measurement of urinary DKK-3, PRO-C6, and C3M levels in patients with ANCA-associated vasculitis (AAV) versus healthy controls showed that uPRO-C6, uC3M, and uDKK-3 were elevated in AAV patients, and uPRO-C6 and uDKK-3 levels were significantly correlated with the degree of renal fibrosis (8); in patients with lupus nephritis (LN), serum and urine PRO-C3 and PRO-C6 are significantly elevated and associate with interstitial fibrosis and tubular atrophy (9). The gene discussed is DKK3; the disease is anti-neutrophil cytoplasmic antibody-associated vasculitis.