what is mthfr gene mutation?
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TRY SITE BELOW FOR FULL INFORMATION
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Because dominant mutations will be selected against.  Keep in mind for all dominant mutations, a phenotype will be expressed, and in a lot of these cases, the gene may not be passed on because the affected person may not be able to reproduce (or will be dead before he/she can reproduce). \n\nRecessive mutations can be carried without expressing a phenotype, so unless both alleles are mutated, no phenotype will be expressed.
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threonine\n\nthere should be a table in your textbook with mRNA codons and corresponding AA's.
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Haemophilia or hemophilia is the name of any of several hereditary genetic illnesses that impair the body's ability to control bleeding. Genetic deficiencies (or, very rarely, an autoimmune disorder) cause lowered plasma clotting factor activity so as to compromise blood-clotting; when a blood vessel is injured, a scab will not form and the vessel can continue to bleed excessively for a very long period of time. The bleeding can be external, if the skin is broken by a scrape, cut or abrasion, or it can be internal, into muscles, joints or hollow organs. It might therefore present visibly as skin bruises, or subtly as melena, hematuria, or bleeding in the brain-.
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I don't have it, but I do know that when it is a familial disorder, it virtually always passes from mother to children, as it is a mitochondrial disorder, and all cellular organelles come from the mother's egg (the sperm basically supply just the DNA).  It can occur sporadically.  It is a A3243G mutation in the mitochondrial genetic code.  A good resource for the "technical" information.  http://www.emedicine.com/ped/topic1406.htm
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Marfan syndrome is a genetic connective tissue disorder characterized by unusually long limbs and fingers. The disease also affects other structures and organs — including the lungs, eyes, heart, blood vessels, dural sac surrounding the spinal cord, and hard palate — in less visible ways. It is named after Antoine Marfan, the French pediatrician who first described it in 1896.\n\nCause\nMarfan syndrome is an autosomal dominant disorder that has been linked to the FBN1 gene on chromosome 15. FBN1 codes for a protein called fibrillin-1, which is essential for the formation of elastic fibers found in connective tissue. Marfan syndrome is also an example of a dominant negative mutation. Marfan syndrome is associated with incomplete penetrance, therefore not all persons carrying the mutation develop the disease. Without the structural support provided by fibrillin, many connective tissues are weakened, which can have severe consequences on support and stability. A related disease has been found in mice, and the study of mouse fibrillin synthesis and secretion, and connective tissue formation, has begun to further our understanding of Marfan syndrome in humans. For instance it has been found that simply reducing the level of normal fibrillin-1 causes the Marfan related disease in mice [1].\n\nMore recently, transforming growth factor β (TGFβ) has been shown to play an important role in Marfan syndrome. Fibrillin-1 binds TGFβ, inactivating it. In Marfan syndrome, reduced levels of fibrillin-1 allow TGFβ to damage the lungs and heart. New treatments for Marfan, using antagonists of TGFβ, are being investigated (Habashi et al., 2006 Science 312(5770):117-21).\n\nDiagnosis\nAlthough genetic testing is available, a diagnosis is usually made solely on clinical findings. A clinical diagnosis uses specific criteria that were established in 1996.[2]\n\n\nEpidemiology\nBecause Marfan syndrome is caused by an autosomal dominant genetic defect, each parent with the condition has a 50 percent chance of passing it on to a child. Most individuals with Marfan syndrome have another affected family member, but about 1/4 to 1/3 of all cases are due to de novo genetic mutations. Such spontaneous mutations occur in about 1 in 20,000 births. Estimates indicate that perhaps 1 in 5,000 people (0.02 percent of the population) have Marfan syndrome. It affects all races and both sexes equally.[3]\n\n\nSymptoms\nThe most serious conditions associated with Marfan syndrome primarily involve the cardiovascular system. Marfan syndrome may cause leakage of the mitral or aortic valves that control the flow of blood through the heart. This may produce shortness of breath, an irregular pulse, and undue tiredness. Another complication is cystic medial necrosis predisposing to dissecting aortic aneurysm.\n\nMarfan syndrome sufferers may grow to larger than normal height, and typically have long, slender limbs and fingers. Sometimes the fingers have a long, thin, spidery appearance known as arachnodactyly. In addition to affecting height and limb proportions, Marfan syndrome may produce other skeletal symptoms. Curvature of the spine (scoliosis) is a common problem, as is abnormal indentation (pectus excavatum) or protrusion (pectus carinatum) of the sternum. These symptoms may in turn cause unusual pressure on the heart and lungs. Other symptoms include; abnormal joint flexibility, high palates, small jaws, flat feet, stooped shoulders, unexplained stretch marks, and dislocation of the optic lens in the eye (ectopia lentis). Some people with Marfans have speech impediments as a result of the high palates and small jaws.\n\nNearsightedness or myopia is a common condition associated with Marfan syndrome. In addition, the weakening of connective tissue often causes detachment of the retina and/or displacement of the lens in one or both eyes.[4]\n\nDural ectasia is a major indicator of Marfan syndrome. It is a dilation of the dural sac surrounding the spinal cord.
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Cystic fibrosis (CF), also called mucoviscidosis, is an autosomal, recessive, hereditary disease of the exocrine glands. It affects the lungs, sweat glands and the digestive system, causing chronic respiratory and digestive problems. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. It is the most common fatal autosomal recessive disease in Caucasians.
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Defination of epistasis - A double mutant where one mutation masks the phenotype of another mutation.\n\nNote that epistasis is not the same thing as dominance. With epistasis a mutation in one gene masks the expression of a different gene. With dominance, one allele of a gene masks the expression of another allele of the same gene.\n\nFor instance, a mutant gene that causes complete baldness would be epistatic to a mutant gene that determines hair color. Likewise, a mutation preventing an early step in a biochemical pathway will be epistatic to a mutation that prevents a step later in the same pathway (that is, an "upstream" mutant phenotype will obscure a "downstream" mutant phenotype). Two examples of how tests of epistasis can be used to analyze biochemical reactions are shown below. \n\n\n\n--------------------------------------------------------------------------------\n\nQUESTION: Two mutations were isolated with different effects on proline utilization: the mutation put-1020 makes cells constitutively express the putP gene at high levels, while the mutation put-1222 prevents expression of the putP gene. To determine if these two mutations affect different "regulatory pathways" or if they both affect the same "regulatory pathway", the double mutant was constructed. The phenotype of the put-1020 put-1222 double mutant is constitutive expression of the putP gene. Suggest a simple explanation for these results. What results would you expect if the two mutations affected different pathways? \n\nANSWER: The put-1020 is epistatic to put-1222. The simplest explanation of these results is that both the put-1020 mutation and the put-1222 mutation affect the same regulatory pathway. If the two mutations affected independent regulatory pathways then the phenotype of the double mutant would probably be intermediate between the two extremes observed in the single mutants. \ncontinues here:\nhttp://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/genetic-analysis/epistasis.html
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Go to answers.com and type molecular mutagensis at search you get links go through them.
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Basically it only takes mutation in one allele to cause Marfan's.  Why?  Because it's autosomal dominant, specifically dominant negative.  What does this mean?  It means that in the heterozygous state, you are making 1/2 normal fibrillin-1, and 1/2 mutant fibrillin-1.  However, normal fibrillin-1 and mutant fibrillin-1 are interacting, and the mutant is making even the normal fibrillin not functional.  Dominant negatives are the result of either proteins with many subunits, or even more commonly, collagen triple helix formation (a condition called osteogenesis imperfecta).  The serious problem with Marfan's is that fibrillin is not properly functioning in the aorta, and it ruptures.
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Interesting question about microbiology. Some recent studies have suggested that many people have a genetic mutation that may result in longer lives.  This mutation is in the mitochrondrial DNA.  You might check out the following websites for more information: www.wired.com/news/medtech and www.imminst.org \nThese sites may go into more detail as to the pathophysiology of the mutation.
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Factor V Leiden Thrombophilia is the most common inherited disorder of blood clotting. It is the result of a specific mutation in the gene for factor V which leads to increased risk for clots in the large veins of the legs (deep venous thrombosis), or clots that travel though the bloodstream and embed in the lungs (pulmonary embolism). It is inherited in an autosomal dominant manner. \nPlease see the webpages for more details on Factor V Leiden syndrome and Anti-coagulants (coumadin).
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in old theoryit might seem that way, but not in real science. many genes and mutations can occurr without any generations having it or even skip generations. the structures of dna and genes have just been discovered to have millions of chromozones in each gene. enviroment has alot to do with genetics also. i have what is called factor v lieden. its a very rare mutation in my dna genes which causes blood clots all the time. at the va hospital, i found i was one of four known in the va system by the chief of staff to have it. they checked for genetics at first but no one in my family ever had a blood clot. just as in aids. there have been many children born from parents who were hiv and never got it. in your theory, the child could get nothing or the fathers 25 %. at what percent were the great, great grandparents. both 100 % or 50/50? the child could also get the great grandparents percentage which is the fathers. even with the mother at 75 and the father at 25. the child could get nothing, the fathers 25 percent or half of his or half of the mothers or half of both.
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HTN, hypertension\nCOPD-chronic obstructive pulmonary disease \nFTT-Failure to thrive\nHA-hydroxylapatite
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Could just be mutations.
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Definition of Missense mutation\n\nMissense mutation: A genetic change involving the substitution of one base in the DNA for another which results in the substitution of one amino acid in a polypeptide for another. A missense mutation is a "readable" genetic message although its "sense" (its meaning) is changed. This is in contrast to a nonsense mutation which has no meaning except to halt the reading of the genetic message. \n\nThe first missense mutation discovered in humans was found to be responsible for sickle hemoglobin, the molecular basis of sickle cell trait and sickle cell anemia. The mutation causes an amino acid change from glutamic acid to valine, converting normal adult hemoglobin (hemoglobin A) to sickle hemoglobin (hemoglobin S). \n\nThe discovery of the sickle missense mutation was made by Vernon Ingram at MIT. In 1956 Dr. Ingram noted that the difference between hemoglobin A and hemoglobin S lay in a single tryptic peptide and then in 1959 reported the precise nature of the missense mutation. This discovery opened the current era of molecular medicine\nMissense mutations or nonsynonymous mutations are types of point mutations where a nucleotide is changed which results in a different amino acid. This in turn can render the resulting protein nonfunctional. Such mutations are responsible for diseases such as Epidermolysis bullosa and sickle-cell disease.\n\nFor example, in sickle-cell disease, the 17th nucleotide of the gene for the beta chain of hemoglobin found on chromosome 11 is erroneously changed from the codon GAG (for glutamic acid) to GTG (which codes valine), so the sixth amino acid is incorrectly substituted.
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get tested for hughs synrome its the underlying cause