ANXA2 and avascular necrosis: Several genes that have a role in bone metabolism were identified through examining associations of AVN with single nucleotide polymorphism (SNPs); Klotho (KL) gene participates in regulation of vitamin D, BMP6 (Bone morphogenic protein) plays a role in bone formation and inflammation and Annexin A2 (ANXA2) gene regulates cell growth and mineralization [78].