|
Profibrillin
Fibrillin-1 is a protein that in humans is encoded by the ''FBN1'' gene, located on chromosome 15. It is a large, extracellular matrix glycoprotein that serves as a structural component of 10-12 nm calcium-binding microfibrils. These microfibrils provide force bearing structural support in elastic and nonelastic connective tissue throughout the body. Mutations altering the protein can result in a variety of phenotypic effects differing widely in their severity, including fetal death, developmental problems, Marfan syndrome or in some cases Weill-Marchesani syndrome. ''FBN1'' gene ''FBN1'' is a 230-kb gene with 65 coding exons that encode a 2,871-amino-acid long proprotein called profibrillin which is proteolytically cleaved near its C-terminus by the enzyme furin convertase to give fibrillin-1, a member of the fibrillin family, and the 140-amino-acid long protein hormone asprosin. FBN-1 protein structure The sequence of fibrillin-1 includes 47 six-cysteine EGF-like d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asprosin
Asprosin is a protein hormone produced by mammals in ( white adipose) tissues that stimulates the liver to release glucose into the blood stream. Asprosin is encoded by the gene ''FBN1'' as part of the protein profibrillin and is released from the C-terminus of the latter by specific proteolysis. In the liver, asprosin activates rapid glucose release via a cyclic adenosine monophosphate ( cAMP)-dependent pathway. Discovery Asprosin was first identified by Dr. Atul Chopra and coworkers at Baylor College of Medicine as a C-terminal cleavage product of the ''FBN1'' gene product profibrillin. They found mutations in the ''FBN1'' gene in two patients with congenital partial lipodystrophy and a progeroid appearance. The two patients were Lizzie Velasquez and Abby Solomon. Truncations of the FBN1 protein in these patients were seen to have two consequences for protein production: a mutant/truncated fibrillin protein and very low plasma asprosin levels (from a postulated dominant negat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germline Mutations
A germline mutation, or germinal mutation, is any detectable variation within germ cells (cells that, when fully developed, become sperm and ova). Mutations in these cells are the only mutations that can be passed on to offspring, when either a mutated sperm or oocyte come together to form a zygote. After this fertilization event occurs, germ cells divide rapidly to produce all of the cells in the body, causing this mutation to be present in every somatic and germline cell in the offspring; this is also known as a constitutional mutation. Germline mutation is distinct from somatic mutation. Germline mutations can be caused by a variety of endogenous (internal) and exogenous (external) factors, and can occur throughout zygote development. A mutation that arises only in germ cells can result in offspring with a genetic condition that is not present in either parent; this is because the mutation is not present in the rest of the parents' body, only the germline. When mutagenes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Idiopathic Scoliosis
Scoliosis is a condition in which a person's spine has a sideways curve. The curve is usually "S"- or "C"-shaped over three dimensions. In some, the degree of curve is stable, while in others, it increases over time. Mild scoliosis does not typically cause problems, but more severe cases can affect breathing and movement. Pain is usually present in adults, and can worsen with age. The cause of most cases is unknown, but it is believed to involve a combination of genetic and environmental factors. Risk factors include other affected family members. It can also occur due to another condition such as muscle spasms, cerebral palsy, Marfan syndrome, and tumors such as neurofibromatosis. Diagnosis is confirmed with X-rays. Scoliosis is typically classified as either structural in which the curve is fixed, or functional in which the underlying spine is normal. Treatment depends on the degree of curve, location, and cause. Minor curves may simply be watched periodically. Treatment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FBN2
Fibrillin is a glycoprotein, which is essential for the formation of elastic fibers found in connective tissue. Fibrillin is secreted into the extracellular matrix by fibroblasts and becomes incorporated into the insoluble microfibrils, which appear to provide a scaffold for deposition of elastin. Clinical aspects Marfan syndrome is a genetic disorder of the connective tissue caused by defected FBN1 gene. Mutations in FBN1 and FBN2 are also sometimes associated with adolescent idiopathic scoliosis. Types Fibrillin-1 Fibrillin-1 is a major component of the microfibrils that form a sheath surrounding the amorphous elastin. It is believed that the microfibrils are composed of end-to-end polymers of fibrillin. To date, 3 forms of fibrillin have been described. The fibrillin-1 protein was isolated by Engvall in 1986, and mutations in the FBN1 gene cause Marfan syndrome Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MASS Phenotype
MASS syndrome is a medical disorder of the connective tissue similar to Marfan syndrome. MASS stands for: Mitral valve prolapse, Aortic root diameter at upper limits of normal for body size, Stretch marks of the skin, and Skeletal conditions similar to Marfan syndrome. It is caused by a mutation in the ''FBN1'' gene, which encodes fibrillin-1. Fibrillin-1 is an extracellular matrix protein that is found in microfibrils; defects in the fibrillin-1 protein cause the malfunctioning of microfibrils, which results in improper stretching of ligaments, blood vessels, and skin. Treatment options for MASS syndrome are largely determined on a case-by-case basis and generally address the symptoms as opposed to the actual disorder; furthermore, due to the similarities between these two disorders, individuals with MASS syndrome follow the same treatment plans as those with Marfan syndrome. Other possible symptoms are mitral valve prolapse, a large aortic root diameter, and myopia. The ske ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectopia Lentis
Ectopia lentis is a displacement or malposition of the eye's crystalline lens from its normal location. A partial dislocation of a lens is termed lens subluxation or subluxated lens; a complete dislocation of a lens is termed lens luxation or luxated lens. Ectopia lentis in dogs and cats Although observed in humans and cats, ectopia lentis is most commonly seen in dogs. Ciliary zonules normally hold the lens in place. Abnormal development of these zonules can lead to primary ectopia lentis, usually a bilateral condition. Luxation can also be a secondary condition, caused by trauma, cataract formation (decrease in lens diameter may stretch and break the zonules), or glaucoma (enlargement of the globe stretches the zonules). Steroid administration weakens the zonules and can lead to luxation, as well. Lens luxation in cats can occur secondary to anterior uveitis (inflammation of the inside of the eye). Anterior lens luxation With anterior lens luxation, the lens pushes into the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marfanoid–progeroid–lipodystrophy Syndrome
Marfanoid–progeroid–lipodystrophy syndrome (MPL), also known as Marfan lipodystrophy syndrome (MFLS) or progeroid fibrillinopathy, is an extremely rare medical condition which manifests as a variety of symptoms including those usually associated with Marfan syndrome, an appearance resembling that seen in neonatal progeroid syndrome (NPS; also known as Wiedemann–Rautenstrauch syndrome), and severe partial lipodystrophy. It is a genetic condition that is caused by mutations in the '' FBN1'' gene, which encodes profibrillin, and affects the cleavage products of profibrillin, fibrillin-1, a fibrous structural protein, and asprosin, a glucogenic protein hormone. As of 2016, fewer than 10 cases of the condition have been reported. Lizzie Velásquez and Abby Solomon have become known publicly through the media for having the condition. In addition to severe lipodystrophy (loss of adipose tissue), individuals with MPL show a concomitant marked loss of lean tissue mass, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastogenesis
Elastic fibers (or yellow fibers) are an essential component of the extracellular matrix composed of bundles of proteins ( elastin) which are produced by a number of different cell types including fibroblasts, endothelial, smooth muscle, and airway epithelial cells. These fibers are able to stretch many times their length, and snap back to their original length when relaxed without loss of energy. Elastic fibers include elastin, elaunin and oxytalan. Elastic tissue is classified as "connective tissue proper". Elastic fibers are formed via elastogenesis, a highly complex process involving several key proteins including fibulin-4, fibulin-5, latent transforming growth factor β binding protein 4, and microfibril associated protein 4. In this process tropoelastin, the soluble monomeric precursor to elastic fibers is produced by elastogenic cells and chaperoned to the cell surface. Following excretion from the cell, tropoelastin self associates into ~200 nm particles by c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinal Detachment
Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blindness. It is a surgical emergency. The retina is a thin layer of light-sensitive tissue on the back wall of the eye. The optical system of the eye focuses light on the retina much like light is focused on the film in a camera. The retina translates that focused image into neural impulses and sends them to the brain via the optic nerve. Occasionally, posterior vitreous detachment, injury or trauma to the eye or head may cause a small tear in the retina. The tear allows vitreous fluid to seep through it under the retina, and peel it away like a bubble in wallpaper. Diagnosis Symptoms As the retina is responsible for vision, persons experiencing a retinal detachment have vision loss. This can be painful or painless. Imaging Ultrasou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pectus Excavatum
Pectus excavatum is a structural deformity of the anterior thoracic wall in which the sternum and rib cage are shaped abnormally. This produces a caved-in or sunken appearance of the chest. It can either be present at birth or develop after puberty. Pectus excavatum can impair cardiac and respiratory function and cause pain in the chest and back. People with the condition may experience severe negative psychosocial effects and avoid activities that expose the chest. Signs and symptoms The hallmark of the condition is a sunken appearance of the sternum. The most common form is a cup-shaped concavity, involving the lower end of the sternum; a broader concavity involving the upper costal cartilages is possible. The lower-most ribs may protrude ("flared ribs"). Pectus excavatum defects may be symmetric or asymmetric. People may also experience chest and back pain, which is usually of musculoskeletal origin. In mild cases, cardiorespiratory function is normal, although the heart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
