In the transgenic tumor necrosis factor (TNF) mouse model, which is characterized by inflammation in multiple joints including the sacroiliac joints, intraarticular joint fusion and ankylosis in the sacroiliac joints can be induced by blockade of dickkopf-1 (DKK-1) – an antagonist of the wingless (wnt) pathway [6]. This evidence concerns the gene DKK1 and ankylosis.