TCF7L2 and atrial fibrillation: While the IVDs used in our study showed no visible signs of degeneration, our analysis did reveal higher expression of Wnt/β-catenin signaling pathway genes LRP3, LGR5 and TCF7L2 in the NP (relative to AF) suggesting that the molecular machinery involved in the initiation of the degenerative process may already be in place much before clinical degeneration occurs later on during the aging process.