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Sclerosteosis
Sclerosteosis is an autosomal recessive disorder characterized by bone overgrowth. It was first described in 1958 but given the current name in 1967. Excessive bone formation is most prominent in the skull, mandible and tubular bones. It can cause facial distortion and syndactyly. Increased intracranial pressure can cause sudden death in patients. It is a rare disorder that is most prominent in the Afrikaner population in South Africa (40 patients), but there have also been cases of American and Brazilian families. Cause Sclerosteosis is caused by mutations in the SOST gene that encodes the sclerostin protein. The sclerostin protein is necessary in inhibiting the Wnt signaling pathway. Wnt signalling results in increased osteoblast activity and RANKL synthesis. Sclerostin therefore increases bone formation by indirectly inhibiting RANKL synthesis and thus osteoclast activation. See also * Van Buchem disease References External links "These Superhumans Are Real and Their DNA C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclerostin
Sclerostin is a protein that in humans is encoded by the ''SOST'' gene. It is a secreted glycoprotein with a C-terminal cysteine knot-like (CTCK) domain and sequence similarity to the DAN (differential screening-selected gene aberrative in neuroblastoma) family of bone morphogenetic protein (BMP) antagonists. Sclerostin is produced primarily by the osteocyte but is also expressed in other tissues, and has anti-anabolic effects on bone formation. Structure The sclerostin protein, with a length of 213 residues, has a secondary structure that has been determined by protein NMR to be 28% beta sheet (6 strands; 32 residues). Function Sclerostin, the product of the SOST gene, located on chromosome 17q12–q21 in humans, was originally believed to be a non-classical bone morphogenetic protein (BMP) antagonist. More recently, sclerostin has been identified as binding to LRP5/ 6 receptors and inhibiting the Wnt signaling pathway. The inhibition of the Wnt pathway leads to decrea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Recessive
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the Phenotype, effect of a different variant of the same gene on Homologous chromosome, the other copy of the chromosome. The first variant is termed dominant and the second is called recessive. This state of having Heterozygosity, two different variants of the same gene on each chromosome is originally caused by a mutation in one of the genes, either new (''de novo'') or Heredity, inherited. The terms autosomal dominant or autosomal recessive are used to describe gene variants on non-sex chromosomes (autosomes) and their associated traits, while those on sex chromosomes (allosomes) are termed X-linked dominant, X-linked recessive or Y-linked; these have an inheritance and presentation pattern that depends on the sex of both the parent and the child (see Sex linkage). Since there is only one Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent parts: the neurocranium and the facial skeleton, which evolved from the first pharyngeal arch. The skull forms the frontmost portion of the axial skeleton and is a product of cephalization and vesicular enlargement of the brain, with several special senses structures such as the eyes, ears, nose, tongue and, in fish, specialized tactile organs such as barbels near the mouth. The skull is composed of three types of bone: cranial bones, facial bones and ossicles, which is made up of a number of fused flat and irregular bones. The cranial bones are joined at firm fibrous junctions called sutures and contains many foramina, fossae, processes, and sinuses. In zoology, the openings in the skull are called fenestrae, the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandible
In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone is the skull's only movable, posable bone, sharing Temporomandibular joint, joints with the cranium's temporal bones. The mandible hosts the lower Human tooth, teeth (their depth delineated by the alveolar process). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels. Amongst other functions, the jawbone is essential for chewing food. Owing to the Neolithic Revolution, Neolithic advent of agriculture (), human jaws evolved to be Human jaw shrinkage, smaller. Although it is the strongest bone of the facial skeleton, the mandible tends to deform in old age; it is also subject to Mandibular fracture, fracturing. Surgery allows for the removal of jawbone fragments (or its entirety) as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syndactyly
Syndactyly is a condition wherein two or more digits are fused together. It occurs normally in some mammals, but is an unusual condition in humans. The term is . Classification Syndactyly can be simple or complex. * In simple syndactyly, adjacent fingers or toes are joined by soft tissue. * In complex syndactyly, the bones of adjacent digits are fused. The kangaroo exhibits complex syndactyly. Syndactyly can be complete or incomplete. * In complete syndactyly, the skin is joined all the way to the tip of the involved digits. * In incomplete syndactyly, the skin is only joined part of the distance to the tip of the involved digits. Complex syndactyly occurs as part of a syndrome (such as Apert syndrome) and typically involves more digits than simple syndactyly. Fenestrated syndactyly, also known as acrosyndactyly or terminal syndactyly, means the skin is joined for most of the digit but in a proximal area there are gaps in the syndactyly with normal skin. This type of synda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afrikaner
Afrikaners () are a Southern African ethnic group descended from predominantly Dutch settlers who first arrived at the Cape of Good Hope in 1652.Entry: Cape Colony. ''Encyclopædia Britannica Volume 4 Part 2: Brain to Casting''. Encyclopædia Britannica, Inc. 1933. James Louis Garvin, editor. Until 1994, they dominated South Africa's politics as well as the country's commercial agricultural sector. Afrikaans, a language which evolved from the Dutch dialect of South Holland, is the mother tongue of Afrikaners and most Cape Coloureds. According to the South African National Census of 2022, 10.6% of South Africans claimed to speak Afrikaans as a first language at home, making it the country's third-largest home language after Zulu and Xhosa. The arrival of Portuguese explorer Vasco da Gama at Calicut, India, in 1498 opened a gateway of free access to Asia from Western Europe around the Cape of Good Hope. This access necessitated the founding and safeguarding of tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic Ocean, South Atlantic and Indian Ocean; to the north by the neighbouring countries of Namibia, Botswana, and Zimbabwe; to the east and northeast by Mozambique and Eswatini; and it encloses Lesotho. Covering an area of , the country has Demographics of South Africa, a population of over 64 million people. Pretoria is the administrative capital, while Cape Town, as the seat of Parliament of South Africa, Parliament, is the legislative capital, and Bloemfontein is regarded as the judicial capital. The largest, most populous city is Johannesburg, followed by Cape Town and Durban. Cradle of Humankind, Archaeological findings suggest that various hominid species existed in South Africa about 2.5 million years ago, and modern humans inhabited the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wnt Signaling Pathway
In cellular biology, the Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt, pronounced "wint", is a portmanteau created from the names Wingless and Int-1. Wnt signaling pathways use either nearby cell-cell communication (paracrine) or same-cell communication (autocrine). They are highly evolutionarily conserved in animals, which means they are similar across animal species from fruit flies to humans. Three Wnt signaling pathways have been characterized: the canonical Wnt pathway, the noncanonical planar cell polarity pathway, and the noncanonical Wnt/calcium pathway. All three pathways are activated by the binding of a Wnt-protein ligand to a Frizzled family receptor, which passes the biological signal to the Dishevelled protein inside the cell. The canonical Wnt pathway leads to regulation of gene transcription, and is thought to be negatively regulated in part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RANKL
Receptor activator of nuclear factor kappa- ligand (RANKL), also known as tumor necrosis factor ligand superfamily member 11 (TNFSF11), TNF-related activation-induced cytokine (TRANCE), osteoprotegerin ligand (OPGL), and osteoclast differentiation factor (ODF), is a protein that in humans is encoded by the ''TNFSF11'' gene. RANKL is known as a type II membrane protein and is a member of the tumor necrosis factor (TNF) superfamily. RANKL has been identified to affect the immune system and control bone regeneration and remodeling. RANKL is an apoptosis regulator gene, a binding partner of osteoprotegerin (OPG), a ligand for the receptor RANK and controls cell proliferation by modifying protein levels of Id4, Id2 and cyclin D1. RANKL is expressed in several tissues and organs including: skeletal muscle, thymus, liver, colon, small intestine, adrenal gland, osteoblast, mammary gland epithelial cells, prostate and pancreas. Variation in concentration levels of RANKL througho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone Formation
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue (mesenchyme), while endochondral ossification involves cartilage as a precursor. In fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in fractures of long bones treated by plaster of Paris, whereas fractures treated by open reduction and internal fixation with metal plates, screws, pins, rods and nails may heal by intramembranous osteogenesis. Heterotopic ossification is a process resulting in the formation of bone tissue that is often atypical, at an extraskeletal location. Calcification is often confused with ossification. Calcification is syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteoclast
An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and bone remodeling, remodeling of bones of the vertebrate, vertebral skeleton. The osteoclast disassembles and digests the composite of hydrated protein and mineral at a molecular level by secreting acid and a collagenase, a process known as ''bone resorption''. This process also helps regulate the level of blood calcium. Osteoclasts are found on those surfaces of bone that are undergoing resorption. On such surfaces, the osteoclasts are seen to be located in shallow depressions called ''resorption bays (Howship's lacunae)''. The resorption bays are created by the erosive action of osteoclasts on the underlying bone. The border of the lower part of an osteoclast exhibits finger-like processes due to the presence of deep infoldings of the cell membrane; this border is called ''ruffled border''. The ruffled border lies in contact with the bone surface within a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Van Buchem Disease
Van Buchem disease, or hyperostosis corticalis generalisata, is an autosomal recessive skeletal disease which is characterised by uninhibited bone growth, especially in the mandible, skull and ribs. The disease was first described in 1955 by Frans van Buchem, when describing two patients of the same family in Urk in the Netherlands. The cause, he found, was that the bone was produced faster than the body broke it down, making it much thicker as the patient got older. The first symptoms experienced by the affected were often deafness and paralysis of the face, caused by the growing bone pinching the nerves. This condition can be traced to a deletion on chromosome 17q. As the disease is recessive, a child will only be affected by the disease if both of the parents are carriers and the child is homozygous for the allele, meaning that they have the allele in duplicate. The gene involved is SOST, and by extension the protein involved is sclerostin. There have been attempts to relieve a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
