The FEATHER (FEbuxostat versus placebo rAndomized controlled Trial regarding reduced renal function in patients with Hyperuricemia complicated by chRonic kidney disease stage 3) study is a prospective, multicenter, double-blind, randomized, placebo-controlled trial of febuxostat—a novel, nonpurine, selective, xanthine oxidase inhibitor. The gene discussed is XDH; the disease is chronic kidney disease.