Since the most debilitating symptom of AKU is a chronic and accelerated form of osteoarthritis (OA), we also investigated structural changes occuring in collagen within OA cartilage matrix. This comparison was designed to test the hypothesis that AKU is an extreme form of OA in which similar molecular changes occur. Our results enabled us to develop a new mechanism for age-related cartilage degeneration that can lead to common osteoarthritis.