Connective Tissue Diseases Essay

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Connective Tissue Diseases Essay

The major component of skin is elastin fibre which can be stretched and returned to its original shape. Ground substances are carbohydrates and carbohydrate-protein complexes; the more common being chondroitin sulphate and hyaluronic acid. The cells of connective tissues may be the migrating type (macrophages, eosinophils, plasma, mast cells) or stationary like adipocytes and fibrocytes (Connective Tissue, 2010).

Tendons and ligaments are dense connective tissues. Loose vascular tissue has the synovial membrane which produces synovial fluid which functions as a lubricant for the joints. Cartilage is a connective tissue that has a large amount of ground tissue responsible for its gel-like consistency and flexibility. Other cartilages are made up of hyaline and elastic fibres. Bone and blood are also connective tissues.Connective Tissue Diseases Essay. Red blood cells comprise blood tissues while calcium phosphate is an important component of bone tissue (Connective Tissue, 2010).

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Connective tissue disorders result when they are damaged and become dysfunctional. There is a wide and diverse range of these diseases, but they can be grouped into three main categories (Connective Tissue Disease, 2010). The first type of connective tissue disorders are autoimmune disorders which occur when one’s own immune system attacks the connective tissues resulting in inflammation and damage. These diseases can be characterized by an overproduction of nuclear antibodies that can be measured in the blood. The second type of connective tissue disorders is due to inherited genetic defects or gene abnormalities. Usually, these disorders also cause tissue abnormalities in other organs like the heart, lungs, eyes, and bones. Some connective tissue disorders also show general symptoms for the early stage of the disorders, but the symptoms may or not progress to full stage disease. These disorders fall under the third and general classification of “undifferentiated connective tissue disorder” or UCTD (Berman, 2003).

Summary

Connective tissue is an important biological tissue composed of an extracellular matrix that binds, anchors, and supports organs. There are various types of connective tissue, all of which consist of varying combinations of fibers, cells, and intercellular substance. Over 200 conditions, which may be inherited or autoimmune, affect connective tissue, and they are collectively known as connective tissue diseases (CTDs). Connective Tissue Diseases Essay. Inherited CTDs are caused by mutations that affect one of the two fibers (collagen and fibrillin). Autoimmune CTDs have no clear etiology, but the incidence is higher in women and among genetically predisposed individuals. As the name suggests, in autoimmune CTDs, the immune system develops antibodies against components of connective tissue. Individual conditions can affect a vast range of bodily structures (including cartilage, blood vessels, bone, tendons, and organs) and thus present with a wide array of clinical findings.

Autoimmune connective tissue diseases

Systemic lupus erythematosus
Rheumatoid arthritis
Inflammatory myopathies (e.g., polymyositis; , dermatomyositis)
Systemic sclerosis
Sjögren’s syndrome
Mixed connective tissue disease (Sharp’s syndrome) Connective Tissue Diseases Essay.
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Inherited connective tissue diseases

Ehlers-Danlos syndrome
Marfan syndrome
Osteogenesis imperfecta
Alport syndrome
Loeys-Dietz syndrome ^[1]
- Autosomal dominant inheritance
- Caused by mutations in TGFβ receptor
- Features shared with Marfan syndrome: marfanoid habitus, increased risk of ascending aortic aneurysms and aortic dissection
- Distinct features: hypertelorism, bifid uvula, cleft palate, easy bruising and keloids, arterial tortuosity (winding course of arteries)

Clinical manifestations of connective tissue disorders

Clinical features vary greatly among individual diseases. The table below provides a general overview of the more common features.

Overview of manifestations of connective tissue disorders
Features	Autoimmune CTDs	Inherited CTDs
General	Fever, weight loss, fatigue	Fatigue, weakness
Musculoskeletal	Polyarthritis, myositis	Joint hypermobility, curved spine, brittle bones, bone deformities, growth abnormalities (short or tall stature)
Skin	Erythema, Raynaud’s phenomenon	Hyperextensive, fragile skin
Other organ manifestations	Heart: pericarditis Lungs: scarring (pulmonary fibrosis), pleurisy Kidneys: nephritis (e.g., glomerulonephritis)Connective Tissue Diseases Essay. CNS: depressive moods	Heart: valve weakness/prolapse Lungs: weakness, difficulty breathing, tendency to develop emphysema Blood vessels: aneurysms, ruptures Eye abnormalities

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Connective tissue disorders

This table lists the most important connective tissue disorders and some examples of their clinical features. For more information on Marfan syndrome, Ehlers-Danlos syndrome, and osteogenesis imperfecta, see the respective articles.

Overview of inherited connective tissue disorders
Condition	Etiology	Pathophysiology	Clinical features (examples)
Marfan syndrome	Autosomal dominant disease caused by mutation of fibrillin-1 gene (FBN1) on chromosome 15	Defective fibrillin → defective elastin → defective connective tissue throughout the body	Tall stature with disproportionately long extremities; jointhypermobility Arachnodactyly Aortic aneurysm and dissection Lens subluxationsuperiorly and temporally Heart valve defects (mitral valve prolapse) Skin hyperelasticity
Ehlers-Danlos syndrome	Heterogeneous group of six connective tissue disorders with variable inheritance (autosomal recessive or dominant) Mutation in genes controlling synthesis of collagen Classic type: mutations in COL5A1, COL5A2 → type Vcollagen defect Vascular type: type IIIprocollagen defect	Defective collagen cross-linking and fibril synthesis	Varying degrees of: Joint hypermobility(most common) Skin hyperextensibility Heart valve defects (particularly mitral valve prolapse) Aneurysms/dissectionsof the iliac, splenic, renal arteries, or the aorta
Menkes disease ^[6]	X-linked recessiveneurodegenerative disease caused by a mutation in the gene ATP7A(coding for Menkes protein, copper-transporting ATPase 1)	Defective copper-transporting ATPase 1 → impaired copper absorption and transport → reduced activity of copper-dependent enzymes (e.g., lysyl oxidase, tyrosinase)→ defective collagen crosslinking and fibril synthesis	Sparse, fragile, kinky hair Hypopigmented skin and hair Failure to thrive Developmental retardation Epilepsy Hypotonia Increased risk of cerebral aneurysm Decreased copper and ceruloplasmin levels
Osteogenesis imperfecta	Rare, autosomal dominantinherited bone disorder due to mutation in COL1A1 or COL1A2genes	Mutation in type I collagen gene → decreased synthesis of type 1 collagen	Brittle bones and frequent and/or multiple fractures from minimal trauma Growth retardation Skeletal deformities Blue sclera Progressive hearing loss(due to abnormal ossicles)
Scurvy	Vitamin C deficiency	Defect in hydroxylation of proline and lysineresidues in procollagen → production of abnormalcollagen with decreased tensile strength	Swollen gums Mucosal bleeding Poor wound healing Curly body hair Follicular hyperkeratosis Hemarthrosis Generalized weakness/fatigue

Connective Tissue Diseases Essay