A functional variant of of IL-1β (-511 C/T, rs16944) is associated with increased susceptibility to PJI as are polymorphisms of the mannose-binding lectin (MBL) (-550 C/G, rs11003125, codon 54 A/G, rs1800450), toll-like receptor 9 (TLR9) (-1486 T/C, rs 187084), and the vitamin D receptor (VDR) (T/C, rs1544410)32,33. Here, TLR9 is linked to juvenile polyposis syndrome.