<P> Osteoporosis--Not inherited genetically, brought on with age, associated with reduced levels of collagen in the skin and bones, growth hormone injections are being researched as a possible treatment to counteract any loss of collagen . </P> <P> Knobloch syndrome--Caused by a mutation in the COL18A1 gene that codes for the production of collagen XVIII . Patients present with protrusion of the brain tissue and degeneration of the retina; an individual who has family members suffering from the disorder is at an increased risk of developing it themselves since there is a hereditary link . </P> <P> Collagen is one of the long, fibrous structural proteins whose functions are quite different from those of globular proteins, such as enzymes . Tough bundles of collagen called collagen fibers are a major component of the extracellular matrix that supports most tissues and gives cells structure from the outside, but collagen is also found inside certain cells . Collagen has great tensile strength, and is the main component of fascia, cartilage, ligaments, tendons, bone and skin . Along with elastin and soft keratin, it is responsible for skin strength and elasticity, and its degradation leads to wrinkles that accompany aging . It strengthens blood vessels and plays a role in tissue development . It is present in the cornea and lens of the eye in crystalline form . It may be one of the most abundant proteins in the fossil record, given that it appears to fossilize frequently, even in bones from the Mesozoic and Paleozoic . </P> <P> Collagen has a wide variety of applications, from food to medical . For instance, it is used in cosmetic surgery and burn surgery . It is widely used in the form of collagen casings for sausages, which are also used in the manufacture of musical strings . </P>

Where is collagen made in the human body