Type III collagen is found primarily in tissues of the body that exhibit elastic properties, like the blood vessels and skin. Some of the body's internal organs also contain this type of collagen. It is often present in areas of the body which also contain type I collagen.
This type of collagen is considered to be a scleroprotein, which is the type of protein used in the construction of muscle fibers and connective tissue. It is fibrous in nature, meaning that it contains elastic qualities as well as the typical qualities of collagen. As a scleroprotein, it is considered to be a somewhat simple protein and is most commonly found in body tissues that contain some sort of cartilage. It is also present in the portion of the eye known as the lens.
Generally found in bones, tendons, and cartilage, type III collagen can also be found in bone marrow and what is known as stroma. Stroma is located in bone marrow, but it functions a bit differently than the rest of that tissue. Various other types of connective tissue can contain this collagen as well. When it reaches the boiling point, a substance known as gelatin is formed.
The gene responsible for the body's production of this collagen has been labeled COL3A1. The protein is designed to provide support and strength for body tissues. Pro-alpha1 chains are the names given to the components of the collagen produced by the COL3A1 gene.
Hundreds of mutations in this particular gene have been discovered by scientists, and they can create some medical issues. Some types of aneurysms, particularly those originating in the aorta, or primary cardiac artery, can result from this type of genetic mutation. An aneurysm is basically a bulging of a blood vessel; if this bulge ruptures, it becomes a medical emergency, as death is a very real possibility.
The most severe forms of a condition known as Ehlers-Danlos syndrome are often attributed to the mutation of the type III collagen gene. With this condition, not enough collagen is produced by the body, which can cause blood vessels and organs to actually rupture. This condition can be life-threatening and requires consistent monitoring by a medical professional.