Respuesta :
A deletion of a particular stretch of chromosome 15 can cause either prader-willi syndrome or angelman syndrome, depending on the parent of origin of the chromosome 15 that becomes deleted.
Why are prader-willi syndrome or angelman syndrome described together?
The clinically separate conditions known as Prader-Willi and Angelman syndromes are linked to numerous abnormalities and mental impairment. They are only treated collectively because they have a comparable and unusual genetic basis: they involve genes that are situated in the same area of the genome and are distinguished by genetic imprinting.
Through the inactivation of one copy of the genes relevant to each disorder—a maternally derived copy of the Prader-Willi syndrome genes in proximal 15q are normally silent, and a paternally derived copy of the one gene for Angelman syndrome in 15q is normally silent—this normal process has contributed to these two severe, complex conditions. When the gene or genes' ordinarily active copy is lacking, abnormality develops in both illnesses.
Both of these disorders typically result from the same chromosomal deletion because the genes for these 2 disorders are very close together and because the center involved in deactivating the genes involved in imprinting may be the same. Which disorder manifests depends on the parent of origin of the chromosome 15 that is deleted. Uniparental disomy, or having both members of the chromosome 15 pair derived from one parent, can also result in Prader-Willi and Angelman syndrome. Both can also be caused by an imprinting mutation, a structural deviation of the imprinting center.
Additionally, Prader-Willi syndrome does not have a comparable origin because it occurs from abnormalities in multiple genes, unlike Angelman syndrome, which can be caused by a mutation in the gene that causes it.
Finally, since DNA methylation is the mechanism by which the genes for these 2 illnesses are imprinted, all save the one gene mutation of the Angelman syndrome gene can be discovered by methylation-sensitive DNA probes. This is true despite the complexity of potential causes. Through the reversal of the imprinting process, this peculiar characteristic of particular regions of the DNA holds hope for the treatment of these and other illnesses connected to imprinting in the future.
To learn more about Prader-Willi and Angelman syndromes with the help of given link:
https://brainly.com/question/13857139
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