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Riboflavin-responsive Exercise Intolerance
Riboflavin-responsive exercise intolerance (SLC25A32 deficiency) is a rare disorder caused by mutations of the SLC25A32 gene that encodes the mitochondrial folate transporter. Patients suffer from exercise intolerance and may have disrupted motor function. A positive correlation between SLC25A32 dysfunction and flavoenzyme deficiency has been observed suggesting that SLC25A32 is in fact a mitochondrial FAD transporter. In mice studies, besides β-oxidation and amino acid metabolism being impaired by mitochondrial FAD deficiency, Slc25a32 wipeout embryos experienced dysfunction of the glycine cleavage system– dihydrolipoamide dehydrogenase. This dihydrolipoamide dehydrogenase dysfunction disrupted folate-mediated one-carbon metabolism, leading a deficiency of 5-methyltetrahydrofolate. Treatment with riboflavin, 5-formyltetrahydrofolate (Folinic acid) and/or L-5-methyltetrahydrofolate (5-MTHF) may lead to a drastic improvement of symptoms. Pyridoxal - 5 - Phosphate (P5P), a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial Folate Transporter
The mitochondrial folate transporter (MTF) is a transport protein that facilitates the transfer of tetrahydrofolate across the inner mitochondrial membrane. It is encoded by the SLC25A32 gene and belongs to the mitochondrial carrier superfamily. History The mitochondrial folate transporter was first described in 2000. Role in pathology Mutations of the SLC25A32 gene cause the condition putatively called "riboflavin-responsive exercise intolerance" (RREI), also known as SLC25A32 deficiency. The first case report linking this condition to SLC25A32 was published in 2016. Several additional cases of SLC25A32 deficiency have been described since. The phenotype of the patients is reminiscent of multiple acyl-CoA dehydrogenase deficiency (MADD). According to a review published in 2020, mutations of the SLC25A32 gene have been shown to cause neural tube defect Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exercise Intolerance
Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe post-exercise pain, fatigue, nausea, vomiting or other negative effects. Exercise intolerance is not a disease or syndrome in and of itself, but can result from various disorders. In most cases, the specific reason that exercise is not tolerated is of considerable significance when trying to isolate the cause down to a specific disease. Dysfunctions involving the pulmonary, cardiovascular or neuromuscular systems have been frequently found to be associated with exercise intolerance, with behavioural causes also playing a part. Signs and symptoms Exercise in this context means physical activity, not specifically exercise in a fitness program. For example, a person with exercise intolerance after a heart attack may not be able to susta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Online Mendelian Inheritance In Man
Online Mendelian Inheritance in Man (OMIM) is a continuously updated catalog of human genes and genetic disorders and traits, with a particular focus on the gene-phenotype relationship. , approximately 9,000 of the over 25,000 entries in OMIM represented phenotypes; the rest represented genes, many of which were related to known phenotypes. Versions and history OMIM is the online continuation of Dr. Victor A. McKusick's ''Mendelian Inheritance in Man'' (MIM), which was published in 12 editions between 1966 and 1998.McKusick, V. A. ''Mendelian Inheritance in Man. Catalogs of Autosomal Dominant, Autosomal Recessive and X-Linked Phenotypes.'' Baltimore, MD: Johns Hopkins University Press, 1st ed, 1996; 2nd ed, 1969; 3rd ed, 1971; 4th ed, 1975; 5th ed, 1978; 6th ed, 1983; 7th ed, 1986; 8th ed, 1988; 9th ed, 1990; 10th ed, 1992. Nearly all of the 1,486 entries in the first edition of MIM discussed phenotypes. MIM/OMIM is produced and curated at the Johns Hopkins School of Medici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Acyl-CoA Dehydrogenase Deficiency
Glutaric acidemia type 2 is an autosomal recessive metabolic disorder that is characterised by defects in the ability of the body to use proteins and fats for energy. Incompletely processed proteins and fats can build up, leading to a dangerous chemical imbalance called acidosis. Genetics Mutations in the '' ETFA'', '' ETFB'', and ''ETFDH'' genes cause glutaric acidemia type II. Mutations in these genes result in a deficiency in one of two enzymes that normally work together in the mitochondria, which are the energy-producing centers of cells. The ETFA and ETFB genes encode two subunits of the enzyme electron transfer flavoprotein, while the ETFDH gene encodes the enzyme electron-transferring-flavoprotein dehydrogenase. When one of these enzymes is defective or missing, the mitochondria cannot function normally, partially broken-down proteins and fats accumulate in the cells and damage them; this damage leads to the signs and symptoms of glutaric acidemia type II. This condi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ragged Red Fibers
MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. It is extremely rare, and has varying degrees of expressivity owing to heteroplasmy. MERRF syndrome affects different parts of the body, particularly the muscles and nervous system. The signs and symptoms of this disorder appear at an early age, generally childhood or adolescence. The causes of MERRF syndrome are difficult to determine, but because it is a mitochondrial disorder, it can be caused by the mutation of nuclear DNA or mitochondrial DNA. The classification of this disease varies from patient to patient, since many individuals do not fall into one specific disease category. The primary features displayed on a person with MERRF include myoclonus, seizures, cerebellar ataxia, myopathy, and ragged red fibers (RRF) on muscle biopsy, leading to the disease's name. Secondary features include dementia, optic atrophy, bilateral deafness, peripheral neuropathy, spasticity, or multiple lipoma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dysarthria
Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. In other words, it is a condition in which problems effectively occur with the muscles that help produce speech, often making it very difficult to pronounce words. It is unrelated to problems with understanding language (that is, dysphasia or aphasia), although a person can have both. Any of the speech subsystems ( respiration, phonation, resonance, prosody, and articulation) can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication. Dysarthria that has progressed to a total loss of speech is referred to as anarthria. The term ''dysarthria'' is from New Latin, ''dys-'' "dysfunctional, impaired" and ''arthr-'' "joint, vocal articulation". Neurological injury due to damage in the central or peripheral nervous system may result in w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ataxia
Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum. Ataxia can be limited to one side of the body, which is referred to as hemiataxia. Several possible causes exist for these patterns of neurological dysfunction. Dystaxia is a mild degree of ataxia. Friedreich's ataxia has gait abnormality as the most commonly presented symptom. The word is from Greek α- negative prefix+ -τάξις rder= "lack of order". Types Cerebellar The term cerebellar ataxia is used to indicate ataxia due to dysfunction of the cerebellum. The cerebellum is responsible for integrating a significant amount of neural information that is used to coordinate smoothly ongoing movements and to participate in motor planning. Althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5,10-Methylenetetrahydrofolate
5,10-Methylenetetrahydrofolate (N5,N10-Methylenetetrahydrofolate; 5,10-CH2-THF) is cofactor in several biochemical reactions. It exists in nature as the diastereoisomer R5,10-methylene-THF. As an intermediate in one-carbon metabolism, 5,10-CH2-THF interconverts to 5-methyltetrahydrofolate, 5-formyltetrahydrofolate, and methenyltetrahydrofolate. It is substrate for the enzyme methylenetetrahydrofolate reductase (MTHFR) It is mainly produced by the reaction of tetrahydrofolate with serine, catalyzed by the enzyme serine hydroxymethyltransferase. Selected functions Formaldehyde detoxification Methylenetetrahydrofolate is an intermediate in the detoxification of formaldehyde. Pyrimidine biosynthesis It is the one-carbon donor for thymidylate synthase, for methylation of 2-deoxy-uridine-5-monophosphate (dUMP) to 2-deoxy-thymidine-5-monophosphate (dTMP). The coenzyme is necessary for the biosynthesis of thymidine and is the C1-donor in the reactions catalyzed by TS and thymid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flavin Adenine Dinucleotide
Flavin may refer to: Placename * Flavin, Aveyron, a commune in southern France Surname * Adrian Flavin (born 1979), a professional rugby player * Christopher Flavin, president of the Worldwatch Institute * Dan Flavin (1933–1996), a minimalist artist famous for using fluorescent light fixtures * Dan Flavin (politician), Louisiana politician * James Flavin (1906–1976), an American character actor * Jennifer Flavin (born 1968), a former model and wife of actor Sylvester Stallone * Martin Flavin (1883–1967), an American playwright and novelist * Martin Flavin (politician) (1841–1917), Irish Nationalist politician, Member of Parliament (MP) for Cork, 1891–1892 * Michael Joseph Flavin (1866-1944), Irish Nationalist politician, Member of Parliament (MP) for North Kerry, 1896-1918 * Mick Flavin, an Irish country singer Biochemistry * Flavin adenine dinucleotide (FAD), a redox cofactor * Flavin-containing amine oxidoreductase, a family of amine oxidases * Flavin-containing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydrofolate
Tetrahydrofolic acid (THFA), or tetrahydrofolate, is a folic acid derivative. Metabolism Human synthesis Tetrahydrofolic acid is produced from dihydrofolic acid by dihydrofolate reductase. This reaction is inhibited by methotrexate. It is converted into 5,10-methylenetetrahydrofolate by serine hydroxymethyltransferase. Bacterial synthesis Many bacteria use dihydropteroate synthetase to produce dihydropteroate, a molecule without function in humans. This makes it a useful target for sulfonamide antibiotics, which compete with the PABA precursor. Functions Tetrahydrofolic acid is a cofactor in many reactions, especially in the synthesis (or anabolism) of amino acids and nucleic acids. In addition, it serves as a carrier molecule for single-carbon moieties, that is, groups containing one carbon atom e.g. methyl, methylene, methenyl, formyl, or formimino. When combined with one such single-carbon moiety as in 10-formyltetrahydrofolate, it acts as a donor of a group w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine Hydroxymethyltransferase
Serine hydroxymethyltransferase (SHMT) is a pyridoxal phosphate (PLP) (Vitamin B6) dependent enzyme () which plays an important role in cellular one-carbon pathways by catalyzing the reversible, simultaneous conversions of L-serine to glycine and tetrahydrofolate (THF) to 5,10-Methylenetetrahydrofolate (5,10-CH2-THF). This reaction provides the largest part of the one-carbon units available to the cell. Structure The structure of the SHMT monomer is similar across prokaryotes and eukaryotes, but whereas the active enzyme is a dimer in prokaryotes, the enzyme exists as a tetramer in eukaryotic cells, though the evolutionary basis for this difference in structure is unknown. However, the evolutionary path taken by SHMT going from prokaryotic dimeric form to the eukaryotic tetrameric form can be easily seen as a sort of doubling event. In other words, the eukaryotic SHMT tetramer resembles two prokaryotic dimers that have packed together, forming what has been described as a � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
