|
L-2-hydroxyglutaric Aciduria
2-hydroxyglutaric aciduria is a rare neurometabolic disorder characterized by the significantly elevated levels of hydroxyglutaric acid in one's urine. It is either autosomal recessive or autosomal dominant. Presentation The signs/symptoms of this condition are consistent with the following: *Intellectual disability, *Muscular hypotonia *Encephalitis *Seizures *Aphasia Cause Mutation in several genes can lead to different types of 2-hydroxyglutaric aciduria. For example, the D2HGDH and L2HGDH genes provide instructions for making enzymes that are found in mitochondria - in which these enzymes break down D-2-hydroxyglutarate and L-2-hydroxyglutarate, respectively, as a part of normal reaction series that generate energy for cell activities. Any mutations occur in either of these genes would interrupt the functional enzymes and allow both 2-hydroxyglutarates to accumulate in cells, which cause 2-hydroxyglutaric aciduria type I. Moreover, it is known that type II for L-2-hydroxygl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-Hydroxyglutaric Acid
α-Hydroxyglutaric acid (2-hydroxyglutaric acid) is an alpha hydroxy acid form of glutaric acid. In biology In humans the compound is formed by a hydroxyacid-oxoacid transhydrogenase whereas in bacteria is formed by a 2-hydroxyglutarate synthase. The compound can be converted to α-ketoglutaric acid through the action of a 2-hydroxyglutarate dehydrogenase which, in humans, are two enzymes called D2HGDH and L2HGDH. Deficiency in either of these two enzymes lead to a disease known as 2-hydroxyglutaric aciduria. D-2-hydroxyglutarate Mutations in isocitrate dehydrogenase (IDH1 and IDH2), which frequently occur in glioma and AML, produce D-2-hydroxyglutarate from alpha-ketoglutarate. D-2-hydroxyglutarate accumulates to very high concentrations which inhibits the function of enzymes that are dependent on alpha-ketoglutarate, including histone lysine demethylases. This leads to a hypermethylated state of DNA and histones, which results in different gene expression that can activa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epilepsy
Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical activity in the brain. These episodes can result in physical injuries, either directly such as broken bones or through causing accidents. In epilepsy, seizures tend to recur and may have no immediate underlying cause. Isolated seizures that are provoked by a specific cause such as poisoning are not deemed to represent epilepsy. People with epilepsy may be treated differently in various areas of the world and experience varying degrees of social stigma due to the alarming nature of their symptoms. The underlying mechanism of epileptic seizures is excessive and abnormal neuronal activity in the cortex of the brain which can be observed in the electroencephalogram (EEG) of an individual. The reason this occurs in most cases of epilepsy is u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
D2HGDH
D-2-hydroxyglutarate dehydrogenase, mitochondrial is an enzyme that in humans is encoded by the ''D2HGDH'' gene. This gene encodes D-2hydroxyglutarate dehydrogenase, a mitochondrial enzyme belonging to the FAD-binding oxidoreductase/transferase type 4 family. This enzyme, which is most active in liver and kidney but also active in heart and brain, converts D-2-hydroxyglutarate to 2-ketoglutarate. Mutations in this gene are present in D-2-hydroxyglutaric aciduria, a rare recessive neurometabolic disorder causing developmental delay, epilepsy, hypotonia, and dysmorphic features. See also * L2HGDH * 2-hydroxyglutarate synthase * 2-hydroxyglutarate dehydrogenase * Hydroxyacid-oxoacid transhydrogenase In enzymology, a hydroxyacid-oxoacid transhydrogenase () is an enzyme that catalyzes the chemical reaction :(S)-3-hydroxybutanoate + 2-oxoglutarate \rightleftharpoons acetoacetate + (R)-2-hydroxyglutarate Thus, the two substrates of this enzym ... References Further reading< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blindness
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment– visual impairment may cause the individual difficulties with normal daily tasks including reading and walking. Low vision is a functional definition of visual impairment that is chronic, uncorrectable with treatment or correctable lenses, and impacts daily living. As such low vision can be used as a disability metric and varies based on an individual's experience, environmental demands, accommodations, and access to services. The American Academy of Ophthalmology defines visual impairment as the best-corrected visual acuity of less than 20/40 in the better eye, and the World Health Organization defines it as a presenting acuity of less than 6/12 in the better eye. The term blindness is used for complete or nearly complete vision loss. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiomyopathy
Cardiomyopathy is a group of diseases that affect the heart muscle. Early on there may be few or no symptoms. As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. An irregular heart beat and fainting may occur. Those affected are at an increased risk of sudden cardiac death. Types of cardiomyopathy include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia, and Takotsubo cardiomyopathy (broken heart syndrome). In hypertrophic cardiomyopathy the heart muscle enlarges and thickens. In dilated cardiomyopathy the ventricles enlarge and weaken. In restrictive cardiomyopathy the ventricle stiffens. In many cases, the cause cannot be determined. Hypertrophic cardiomyopathy is usually inherited, whereas dilated cardiomyopathy is inherited in about one third of cases. Dilated cardiomyopathy may also result from alcohol, heavy m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrocephaly
Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a familial genetic characteristic. People diagnosed with macrocephaly will receive further medical tests to determine whether the syndrome is accompanied by particular disorders. Those with benign or familial macrocephaly are considered to have megalencephaly. Causes Many people with abnormally large heads or large skulls are healthy, but macrocephaly may be pathological. Pathologic macrocephaly may be due to megalencephaly (enlarged brain), hydrocephalus (abnormally increased cerebrospinal fluid), cranial hyperostosis (bone overgrowth), and other conditions. Pathologic macrocephaly is called "syndromic", when it is associated with any other noteworthy condition, and "nonsyndromic" otherwise. Pathologic macrocephaly may be caused by congenital anatomic abnormalities, genetic conditions, or by environmental events. Many genetic conditions are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolite Damage And Its Repair Or Pre-emption
Metabolite damage can occur through enzyme promiscuity or spontaneous chemical reactions. Many metabolites are Chemical reaction, chemically reactive and unstable and can react with other cell components or undergo unwanted modifications. Enzymatically or chemically damaged metabolites are always useless and often toxic. To prevent toxicity that can occur from the accumulation of damaged metabolites, organisms have damage-control systems that: # Reconvert damaged metabolites to their original, undamaged form (damage repair) # Convert a potentially harmful metabolite to a benign one (damage pre-emption) # Prevent damage from happening by limiting the build-up of reactive, but non-damaged metabolites that can lead to harmful products (directed overflow) Damage-control systems can involve one or more specific enzymes. Types of damage Similarly to DNA and proteins, metabolites are prone to damage, which can occur chemically or through enzyme promiscuity. Much less is known about metabo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malate Dehydrogenase
Malate dehydrogenase () (MDH) is an enzyme that reversibly catalyzes the oxidation of malate to oxaloacetate using the reduction of NAD+ to NADH. This reaction is part of many metabolic pathways, including the citric acid cycle. Other malate dehydrogenases, which have other EC numbers and catalyze other reactions oxidizing malate, have qualified names like malate dehydrogenase (NADP+). Isozymes Several isozymes of malate dehydrogenase exist. There are two main isoforms in eukaryotic cells. One is found in the mitochondrial matrix, participating as a key enzyme in the citric acid cycle that catalyzes the oxidation of malate. The other is found in the cytoplasm, assisting the malate-aspartate shuttle with exchanging reducing equivalents so that malate can pass through the mitochondrial membrane to be transformed into oxaloacetate for further cellular processes. Humans and most other mammals express the following two malate dehydrogenases: Protein families The m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Promiscuity
Enzyme promiscuity is the ability of an enzyme to catalyse a fortuitous side reaction in addition to its main reaction. Although enzymes are remarkably specific catalysts, they can often perform side reactions in addition to their main, native catalytic activity. These promiscuous activities are usually slow relative to the main activity and are under neutral selection. Despite ordinarily being physiologically irrelevant, under new selective pressures these activities may confer a fitness benefit therefore prompting the evolution of the formerly promiscuous activity to become the new main activity. An example of this is the atrazine chlorohydrolase (''atzA'' encoded) from '' Pseudomonas sp.'' ADP that evolved from melamine deaminase (''triA'' encoded), which has very small promiscuous activity toward atrazine, a man-made chemical. Introduction Enzymes are evolved to catalyse a particular reaction on a particular substrate with a high catalytic efficiency (''kcat/KM'', ''cf''. Michae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L2HGDH
L-2-hydroxyglutarate dehydrogenase, mitochondrial is an enzyme that in humans is encoded by the ''L2HGDH'' gene, also known as C14orf160, on chromosome 14. Function This gene encodes L-2-hydroxyglutarate dehydrogenase, a flavin adenine dinucleotide (FAD)-dependent enzyme that oxidizes Alpha-Hydroxyglutaric acid, L-2-hydroxyglutarate to alpha-ketoglutarate in a variety of mammalian tissues. Mutations in this gene cause L-2-hydroxyglutaric aciduria, a rare autosomal recessive neurometabolic disorder resulting in moderate to severe mental retardation. L2HGDH codes for a protein that is 50 kDa in size. The L2HGDH protein contains a mitochondrial-targeting transit peptide and is localized to the mitochondrial inner membrane inside mitochondria inside the cell. The L2HGDH protein catalyzes the following reaction, and requires flavin adenine dinucleotide (FAD) as a Cofactor (biochemistry), co-factor: (S)-2-hydroxyglutarate + acceptor = 2-oxoglutarate + reduced acceptor. L-2-hydrox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychomotor Learning
Psychomotor learning is the relationship between cognitive functions and physical movement. Psychomotor learning is demonstrated by physical skills such as movement, coordination, manipulation, dexterity, grace, strength, speed—actions which demonstrate the fine or gross motor skills, such as use of precision instruments or tools, and walking. Sports and dance are the richest realms of gross psychomotor skills. Behavioral examples include driving a car, throwing a ball, and playing a musical instrument. In psychomotor learning research, attention is given to the learning of coordinated activity involving the arms, hands, fingers, and feet, while verbal processes are not emphasized. Stages of psychomotor development According to Paul Fitts and Michael Posner's three-stage model, when learning psychomotor skills, individuals progress through the cognitive stages, the associative stage, and the autonomic stage. The cognitive stage is marked by awkward slow and choppy movem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mental Retardation
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation,Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by significantly impaired intellectual and adaptive functioning. It is defined by an IQ under 70, in addition to deficits in two or more adaptive behaviors that affect everyday, general living. Intellectual functions are defined under DSM-V as reasoning, problem‑solving, planning, abstract thinking, judgment, academic learning, and learning from instruction and experience, and practical understanding confirmed by both clinical assessment and standardized tests. Adaptive behavior is defined in terms of conceptual, social, and practical skills involving tasks performed by people in their everyday lives. Intellectual disability is subdivided into syndromic intellectual disability, in which intellectual deficits associated with other medical and beh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
