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Spinal Muscular Atrophy With Lower Extremity Predominance 1
Spinal muscular atrophy with lower extremity predominance 1 (SMALED1) is an extremely rare neuromuscular disorder of infants characterised by severe progressive muscle atrophy which is especially prominent in legs. The disorder is associated with a genetic mutation in the '' DYNC1H1'' gene (the gene responsible also for one of the axonal types of Charcot–Marie–Tooth disease) and is inherited in an autosomal dominant manner. As with many genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...s, there is no known cure to SMALED1. The condition was first described in a multi-generational family by Walter Timme in 1917. Its linkage to the ''DYNC1H1'' gene was discovered in 2010 by M. B. Harms, et al., who also proposed the current name of the disorder. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Dominant
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and the second recessive. This state of having 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 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 copy of the Y chromosome, Y-linked traits cannot be dominant or recessive. Additionally, there are other forms of dominance such as incomple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Atrophy
Muscle atrophy is the loss of skeletal muscle mass. It can be caused by immobility, aging, malnutrition, medications, or a wide range of injuries or diseases that impact the musculoskeletal or nervous system. Muscle atrophy leads to muscle weakness and causes disability. Disuse causes rapid muscle atrophy and often occurs during injury or illness that requires immobilization of a limb or bed rest. Depending on the duration of disuse and the health of the individual, this may be fully reversed with activity. Malnutrition first causes fat loss but may progress to muscle atrophy in prolonged starvation and can be reversed with nutritional therapy. In contrast, cachexia is a wasting syndrome caused by an underlying disease such as cancer that causes dramatic muscle atrophy and cannot be completely reversed with nutritional therapy. Sarcopenia is age-related muscle atrophy and can be slowed by exercise. Finally, diseases of the muscles such as muscular dystrophy or myopathies can caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DYNC1H1
Cytoplasmic dynein 1 heavy chain 1 is a protein that in humans is encoded by the ''DYNC1H1'' gene. Interactions DYNC1H1 has been shown to interact with PAFAH1B1 and CDC5L. Clinical relevance Mutations in this gene have been shown to cause dominant axonal Charcot-Marie-Tooth disease as well as spinal muscular atrophy with lower extremity predominance 1 Spinal muscular atrophy with lower extremity predominance 1 (SMALED1) is an extremely rare neuromuscular disorder of infants characterised by severe progressive muscle atrophy which is especially prominent in legs. The disorder is associated wit ... (SMA-LED1). References Further reading * * * * * * * * * * * * * * * * * * External links * {{gene-14-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrophy
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, excessive amount of apoptosis of cells, and disuse or lack of exercise or disease intrinsic to the tissue itself. In medical practice, hormonal and nerve inputs that maintain an organ or body part are said to have ''trophic'' effects. A diminished muscular trophic condition is designated as ''atrophy''. Atrophy is reduction in size of cell, organ or tissue, after attaining its normal mature growth. In contrast, hypoplasia is the reduction in the cellular numbers of an organ, or tissue that has not attained normal maturity. Atrophy is the general physiological process of reabsorption and breakdown of tissues, involving apoptosis. When it occurs as a result of disease or loss of trophic support because of other diseas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication ( translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics ( phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charcot–Marie–Tooth Disease
Charcot–Marie–Tooth disease (CMT) is a hereditary motor and sensory neuropathy of the peripheral nervous system characterized by progressive loss of muscle tissue and touch sensation across various parts of the body. This disease is the most commonly inherited neurological disorder, affecting about one in 2,500 people. It is named after those who classically described it: the Frenchman Jean-Martin Charcot (1825–1893), his pupil Pierre Marie (1853–1940), and the Briton Howard Henry Tooth (1856–1925). There is no known cure. Care focuses on maintaining function. CMT was previously classified as a subtype of muscular dystrophy. Signs and symptoms Symptoms of CMT usually begin in early childhood or early adulthood but can begin later. Some people do not experience symptoms until their early 30s or 40s. Usually, the initial symptom is foot drop early in the course of the disease. This can also cause hammertoe, where the toes are always curled. Wasting of muscle tissue of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inheritance
Inheritance is the practice of receiving private property, titles, debts, entitlements, privileges, rights, and obligations upon the death of an individual. The rules of inheritance differ among societies and have changed over time. Officially bequeathing private property and/or debts can be performed by a testator via will, as attested by a notary or by other lawful means. Terminology In law, an ''heir'' is a person who is entitled to receive a share of the deceased's (the person who died) property, subject to the rules of inheritance in the jurisdiction of which the deceased was a citizen or where the deceased (decedent) died or owned property at the time of death. The inheritance may be either under the terms of a will or by intestate laws if the deceased had no will. However, the will must comply with the laws of the jurisdiction at the time it was created or it will be declared invalid (for example, some states do not recognise handwritten wills as valid, or on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development (a ''de novo'' mutation), or it can be inherited from two parents who are carriers of a faulty gene (autosomal recessive inheritance) or from a parent with the disorder (autosomal dominant inheritance). When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA (due to their size). There are well over 6,000 known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Muscular Atrophies
Spinal muscular atrophies (SMAs) are a genetically and clinically heterogeneous group of rare debilitating disorders characterised by the degeneration of lower motor neurons (neuronal cells situated in the anterior horn of the spinal cord) and subsequent atrophy (wasting) of various muscle groups in the body. While some SMAs lead to early infant death, other diseases of this group permit normal adult life with only mild weakness. Classification Based on the type of muscles affected, spinal muscular atrophies can be divided into: * ''Proximal spinal muscular atrophies'', i.e., conditions that affect primarily proximal muscles; * ''Distal spinal muscular atrophies'' (which significantly overlap with distal hereditary motor neuronopathies) where they affect primarily distal muscles. When taking into account prevalence, spinal muscular atrophies are traditionally divided into: * '' Autosomal recessive proximal spinal muscular atrophy'', responsible for 90-95% of cases and usual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Muscular Atrophy With Lower Extremity Predominance 2A
Spinal muscular atrophy with lower extremity predominance 2A (SMALED2A) is a rare neuromuscular disorder characterised by muscle weakness predominantly in legs. The disorder is usually diagnosed shortly after birth; affected children have a delayed motor development, waddling gait, difficulties walking, sometimes develop spasticity. Sensation, swallowing and cognitive development are not affected. The disorder is slowly progressive throughout the lifetime. The disease is caused by a mutation in the ''BICD2'' gene and is passed on in an autosomal dominant manner. There is no known cure for SMALED2A. See also * Spinal muscular atrophies * Spinal muscular atrophy with lower extremity predominance 1 Spinal muscular atrophy with lower extremity predominance 1 (SMALED1) is an extremely rare neuromuscular disorder of infants characterised by severe progressive muscle atrophy which is especially prominent in legs. The disorder is associated wit ... * Spinal muscular atrophy with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Muscular Atrophy With Lower Extremity Predominance 2B
Spinal muscular atrophy with lower extremity predominance 2B (SMALED2B) is a rare neuromuscular disorder characterised by generalised muscle weakness. Indications Decreased foetal movement is apparent already before birth. The child is born with a generalised muscle weakness (hypotonia) and contractures resembling arthrogryposis multiplex congenita, respiratory insufficiency, and sometimes facial deformations. The disorder is frequently fatal in early childhood. Cause The disease is caused by a mutation in the ''BICD2'' gene and is passed on in an autosomal dominant manner. There is no known cure to SMALED2B. See also * Spinal muscular atrophies * Spinal muscular atrophy with lower extremity predominance 1 * Spinal muscular atrophy with lower extremity predominance 2A Spinal muscular atrophy with lower extremity predominance 2A (SMALED2A) is a rare neuromuscular disorder characterised by muscle weakness predominantly in legs. The disorder is usually diagnosed shortly af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
