A permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people.
| Print |. This section defines the types of mutations found in the dystrophin gene, including deletions, duplications, and point mutations. Note: The terminology used to describe dystrophin mutations is evolving, as is our understanding of the frequency of each type of mutation.  Types of mutations. In order for a mutation to be inherited, it must occur in the genetic material of a sex cell. It is likely that most sex cells contain gene mutations of some sort. It is now thought that the frequency of new mutations in humans is about 1 for every 10,000 genes per generation A gene mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people. Mutations range in size; they can affect anywhere from a single DNA building block (base pair) to a large segment of a chromosome that includes multiple genes. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if a mistake is made as DNA copies itself during cell division. Acquired mutations in somatic cells (cells other than sperm and egg cells) cannot be passed on to the next generation. The methylenetetrahydrofolate reductase (MTHFR) mutation test is used to detect two relatively common mutations in the MTHFR gene that are associated with elevated levels of homocysteine in the blood. If the MTHFR mutation test is negative, then the C677T and A1298C mutations were not detected and the tested person's elevated homocysteine level is likely due to another cause. Other, more rare MTHFR genetic mutations will not be detected with typical testing. 1 Silent Mutation: Although a change in the DNA sequence occurs, this type of mutation does not change the protein that is to be produced. 2  This is because multiple genetic codons can encode for the same amino acid. 3  Amino acids are coded for by three nucleotide sets called codons. 1 Nonsense Mutation: This type of mutation alters the nucleotide sequence so that a stop codon is coded for in place of an amino acid. 2  A stop codon signals the end of the translation process and stops protein production. Mutations can also occur in which nucleotide base pairs are inserted into or deleted from the original gene sequence. This type of gene mutation is dangerous because it alters the template from which amino acids are read. 1 Nonsense Mutation: This type of mutation alters the nucleotide sequence so that a stop codon is coded for in place of an amino acid. 2  A stop codon signals the end of the translation process and stops protein production. Of these, MTHFR C677T and A1298C mutations are among the most common. If a person has two copies (homozygous) of MTHFR C677T, or has one copy of C677T and one of A1298C, then it is likely that elevated homocysteine levels are due to these inherited mutations, or that the mutations are contributing to them. If the MTHFR mutation test is negative, then the C677T and A1298C mutations were not detected and the tested person's elevated homocysteine level is likely due to another cause. Other, more rare MTHFR genetic mutations will not be detected with typical testing. The methylenetetrahydrofolate reductase (MTHFR) gene contains the DNA code to produce the MTHFR enzyme. This test detects two of the most common mutations. When there are mutations or variations in the MTHFR gene, it can lead to serious genetic disorders such as homocystinuria, anencephaly, spina bifida, and others. The MTHFR enzyme is critical for metabolizing one form of B vitamin, folate, into another Mutations cause changes in the genetic code that lead to genetic variation and the potential to develop disease. Gene mutations can be generally categorized into two types: point mutations and base-pair insertions or deletions. Point mutations are the most common type of gene mutation. Also called a base-pair substitution, this type of mutation changes a single nucleotide base pair. 1 Nonsense Mutation: This type of mutation alters the nucleotide sequence so that a stop codon is coded for in place of an amino acid. 2  A stop codon signals the end of the translation process and stops protein production. When a person has two copies of the MTHFR C677T gene mutation (homozygous) or one copy of MTHFR C677T and one copy of A1298C (compound heterozygous), decreased MTHFR enzyme activity slows down the homocysteine-to-methionine conversion process and can lead to a buildup of homocysteine in the blood. This test detects two of the most common mutations. When there are mutations or variations in the MTHFR gene, it can lead to serious genetic disorders such as homocystinuria, anencephaly, spina bifida, and others.
http://research.duchenneconnect.org/index.php?option=com_content&view=article&id=154&Itemid=240 http://anthro.palomar.edu/synthetic/synth_3.htm http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation https://labtestsonline.org/understanding/analytes/mthfr/tab/test http://biology.about.com/od/basicgenetics/ss/gene-mutation.htm http://biology.about.com/od/basicgenetics/ss/gene-mutation.htm https://labtestsonline.org/understanding/analytes/mthfr/tab/test https://labtestsonline.org/understanding/analytes/mthfr/tab/sample http://biology.about.com/od/basicgenetics/ss/gene-mutation.htm https://labtestsonline.org/understanding/analytes/mthfr/tab/sample
what is a gene/DNA mutation