Genetic heterogeneity - Genetic heterogeneity This is the...

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Genetic heterogeneity This is the term used to describe a condition which may be caused by mutations in more than one gene. Tuberous sclerosis again provides a good example of this, the identical disease is produced by mutations in either of two unrelated genes, TSC1 on chromosome 9 or TSC2 on chromosome 16. In such cases, presumably both genes act at different points in the same biochemical or regulatory pathway. Or perhaps one provides a ligand and one a receptor. variable expressivity The degree to which a disease may manifest itself can be very variable and, once again, tuberous sclerosis provides a good example. Some individuals scarcely have any symptoms at all whereas others are severely affected. Sometimes very mild symptoms may be overlooked and then a person may be wrongly classified as non-affected. Clearly this could have profound implications for genetic counselling. Incomplete Penetrance
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Genetic heterogeneity - Genetic heterogeneity This is the...

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