The IVD endplates and AF can respond to the same mechanical loads and stresses experienced by the NP by using N‐cadherin‐negative chondrocytes and fibroblasts to maintain their ECM (Sakai et al., 2009), whose proteoglycan to collagen ratio (measured as the ratio of glycosaminoglycans to hydroxyproline) is about 2:1 compared to the much higher 27:1 for NP ECM (Mwale, Roughley & Antoniou, 2004). This evidence concerns the gene CDH2 and atrial fibrillation.