Genetic disorders: Difference between revisions
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Genetic disorders are diseases of anatomical or physiological function caused by inherent or sporadic mutations in the DNA sequence of one or more genes. The disease can be either familial, | Genetic disorders are diseases of anatomical or physiological function caused by inherent or sporadic mutations in the [[DNA|DNA]] sequence of one or more genes. The disease can be either familial, i.e. inherited from one or both parents, or sporadic, i.e. a random mutation based upon environmental factors. (NB: some genetic diseases can be either of these, for example familial or sporadic retinoblastoma.) | ||
DNA mutations can manifest in a number of different ways, such as: | DNA mutations can manifest in a number of different ways, such as: | ||
Deletions: eg. Cystic fibrosis - ΔF508 | Deletions: eg. [[Cystic_fibrosis|Cystic fibrosis]] - ΔF508 | ||
Insertions: eg. Huntington's disease - CAG repeats | Insertions: eg. [[Huntington's_Disease|Huntington's disease]] - CAG repeats | ||
Point mutations: | [[Point mutation|Point mutations]]: | ||
*[[Silent_mutation|Silent mutation]]: does not cause disease, as the substituted base still causes the codon to transcribe the same amino acid. | |||
*[[Missense mutation|Missense mutation]]: causes another amino acid to be transcribed eg. [[Sickle_Cell|Sickle-cell anaemia]] - E6V | |||
*[[Nonsense_mutation|Nonsense mutation]]: causes a premature stop codon to be transcribed, thereby truncating the protein e.g. α [[thalassemia|thalassemia]] | |||
These mutations only occur on a small scale and can still have disastrous effects, whereas there are some mutations types that occur on a large scale, such as: | These mutations only occur on a small scale and can still have disastrous effects, whereas there are some mutations types that occur on a large scale, such as: | ||
Latest revision as of 00:47, 23 October 2013
Genetic disorders are diseases of anatomical or physiological function caused by inherent or sporadic mutations in the DNA sequence of one or more genes. The disease can be either familial, i.e. inherited from one or both parents, or sporadic, i.e. a random mutation based upon environmental factors. (NB: some genetic diseases can be either of these, for example familial or sporadic retinoblastoma.)
DNA mutations can manifest in a number of different ways, such as:
Deletions: eg. Cystic fibrosis - ΔF508
Insertions: eg. Huntington's disease - CAG repeats
- Silent mutation: does not cause disease, as the substituted base still causes the codon to transcribe the same amino acid.
- Missense mutation: causes another amino acid to be transcribed eg. Sickle-cell anaemia - E6V
- Nonsense mutation: causes a premature stop codon to be transcribed, thereby truncating the protein e.g. α thalassemia
These mutations only occur on a small scale and can still have disastrous effects, whereas there are some mutations types that occur on a large scale, such as:
Amplifications / gene duplications
Chromosomal / whole gene deletions
Loss of heterozygosity