Further studies have shown that xanthine oxidase (XO) [15], nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) (NOX) [16], and signals such as phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) [17], mitogen-activated protein kinase (MAPK), and NET, which are closely related to ROS production and metabolism, are abnormally active in hyperuricemia or GA development. This evidence concerns the gene XDH and hyperuricemia.