Connective tissue is the material inside your body that joins and supports many of its parts. It is the “cellular glue” that gives your tissues shape and helps keep them strong. Connective tissue also helps some of your tissues do their work. Cartilage and fat are examples of connective tissue.
Connective tissues form a framework, or matrix, for the human body, and are composed of two major structural protein molecules: collagen and elastin. There are many different types of collagen protein in each of the body’s tissues.
Elastin is capable of stretching and returning to its original length, much like a spring or rubber band. Elastin is the major component of ligaments, which are tissues that attach bone to bone, and skin. In patients with connective tissue disease, it is common for collagen and elastin to become injured due to inflammation. Many connective tissue diseases feature abnormal immune system activity demonstrated by inflammation in tissues due to an immune system that is directed against one’s own body tissues (this is why it is called an “autoimmunity” disorder).
There are several hundred disorders that impact the body’s connective tissue. Connective tissue diseases can have strong or weak inheritance risks, and may also be caused by environmental factors. Some connective tissue disorders are the result of an infection, such as cellulitis. Injuries can also cause connective tissue disorders, such as scarring after trauma. Others, are genetic, such as Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta. Still others have no known cause, like scleroderma. Each disorder has its own symptoms and needs different treatment.
Diseases involving inflammation or weakness of collagen are referred to as collagen diseases. Collagen vascular diseases can be (but are not necessarily) associated with collagen and blood vessel abnormalities that are autoimmune in nature.
Autoimmune Connective Tissue Disorders
Autoimmune CTDs are also referred to as systemic autoimmune diseases. They may have both genetic and environmental causes. Genetic factors may cause an individual’s predisposition towards developing these autoimmune diseases. As a group they are characterized by the presence of spontaneous overactivity of the immune system, which results in the production of extra antibodies into the circulation. Classic collagen vascular diseases have a “classic” presentation with typical findings that doctors can identify during an examination. Each disease also has “classic” blood test abnormalities and abnormal antibody patterns. Each of these diseases can evolve slowly or rapidly from very subtle abnormalities before demonstrating the classic features that assist in the diagnosis. The classic collagen vascular diseases include:
- Systemic Lupus Erythematosus (SLE) – An inflammation of the connective tissues, SLE can afflict every organ system. It is up to nine times more common in women than men and strikes black women three times as often as white women. The condition is aggravated by sunlight.
- Rheumatoid arthritis – Rheumatoid arthritis is a systemic disorder in which immune cells attack and inflame the membrane around joints. It also can affect the heart, lungs, and eyes. Of the estimated 2.1 million Americans with rheumatoid arthritis, approximately 1.5 million (71 percent) are women.
- Scleroderma – an activation of immune cells that produces scar tissue in the skin, internal organs, and small blood vessels. It affects women three times more often than men overall, but increases to a rate 15 times greater for women during childbearing years, and appears to be more common among black women.
- Sjögren’s syndrome – also called Sjögren’s disease, is a chronic, slowly progressing inability to secrete saliva and tears. It can occur alone or with rheumatoid arthritis, scleroderma, or systemic lupus erythematosus. Nine out of 10 cases occur in women, most often at or around mid-life.
- Mixed connective tissue disease – Mixed connective-tissue disease (MCTD) is a disorder in which features of various connective-tissue diseases (CTDs) such as systemic lupus erythematosus (SLE); systemic sclerosis (SSc); dermatomyositis (DM); polymyositis (PM); anti-synthetase syndrome; and, occasionally, Sjögren syndrome can coexist and overlap. The course of the disease is chronic and usually milder than other CTDs. In most cases, MCTD is considered an intermediate stage of a disease that eventually becomes either SLE or Scleroderma.
- Psoriatic arthritis is also a collagen vascular disease.
Heritable Connective Tissue Disorders
Heritable (genetic) disorders of connective tissue are a family of more than 200 disorders that affect connective tissues. These disorders result from alterations (mutations) in genes, and thus are called “heritable.” All of these diseases are directly related to mutations in genes that are responsible for building tissues. Alterations in these genes may change the structure and development of skin, bones, joints, the heart, blood vessels, lungs, eyes, and ears. Some mutations also change how these tissues work.
- Marfan syndrome – a genetic disease causing abnormal fibrillin.
- Peyronie’s disease- involving the growth of abnormal collagen (Type I and III) in the penis.
- Ehlers-Danlos syndrome – defect in the synthesis of collagen (Type I or III) causes progressive deterioration of collagens, with different EDS types affecting different sites in the body, such as joints, heart valves, organ walls, arterial walls.
- Osteogenesis imperfecta (brittle bone disease) – caused by insufficient production of normal collagen (primarily type I) to produce healthy, strong bones.
- Stickler syndrome – affects collagen (primarily type II and XI), and may result in a distinctive facial appearance, eye abnormalities, hearing loss, and joint problems.
- Alport syndrome – defects in collagen (type IV), found in the renal basement membrane, inner ear and eyes, leading to glomerulonephritis, hearing loss, and eye disease, respectively.
- Congenital contractural arachnodactyly – Also known as Beal’s syndrome. It is akin to Marfan syndrome but with Contractures of hip, knee, elbows and ankle joint and crumpled ear.
- Loeys–Dietz syndrome- The disorder is marked by aneurysms in the aorta, often in children. Symptoms appear to be like Marfan Syndrome and EDS. This is caused by a mutation in the gene TGFBR on either chromosome 3 or 9 depending on the type. Discovered in 2005.
If you have a connective tissue disorder and are unable to work, you may qualify for long term disability insurance benefits.