Age dependant reduction in PGs, IVD hydration, ECM biomechanical competence. Early IVDD in ChD canine compared to non‐ChD due to relative decline in notochordal cell numbers. SM/J mouse early onset spontaneous IVDD. NP cell death, degeneration of NP, AF, CEP. Elevated expression of Col10a1, Ctgf, Runx2 and chondrocyte hypertrophy. This evidence concerns the gene RUNX2 and atrial fibrillation.