Collagen type II is the most abundant protein of cartilage matrix. Two isoforms exist and collagen type IIA is involved in early development of cartilage in embryos. The collagen is produced from type II procollagen when two teloterminal propeptides are digested from the procursor and released into the circulation. Procollagen type II N-terminal propeptide (PIIANP) is considered a marker of cartilage synthesis and the normal concentration in serum is approximately 30 ng/mL.
Alpha-1 type II collagen; arthroophthalmopathy, progressive (Stickler syndrome); cartilage collagen; Chondrocalcin; Collagen alpha-1(II) chain; collagen II, alpha-1 polypeptide; collagen, type II, alpha 1; Procollagen IIA N-proteinase