Collagen hereditary link. 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
Mixed connective tissue disease Mixed connective tissue disease Mixed connective tissue disease (also known as Sharp's syndrome), commonly abbreviated as MCTD, is an autoimmune disease characterized by the presence of high blood levels of a specific autoantibody, now called anti-U1 ribonucleoprotein (RNP). The idea behind the "mixed" disease is that this specific autoantibody is also present in other autoimmune diseases such as systemic lupus erythematosus, polymyositis, scleroderma, etc. It was characterized in 1972, and the term was introduced by Leroy in 1980. It is sometimes said to be the same as undifferentiated connective tissue disease, but other experts specifically reject this idea because undifferentiated