Trinucleotide repeat disorders are an umbrella group of genetic diseases that have been well described clinically for a long time; however, the scientific community is only beginning to understand their molecular basis. They are classified in two basic groups depending on the location of the relevant triplet repeats in a coding or a non-coding region of the genome. Repeat expansion past a disease-specific threshold results in molecular and cellular abnormalities that manifest themselves as disease symptoms. Repeat expansion is postulated to occur via slippage during DNA replication and/or transcription-mediated DNA repair. Trinucleotide repeat disorders are characterized by genetic anticipation, which is defined by the increasing severity and earlier onset of a disease as it is inherited through consecutive generations. Through the analysis of Huntington’s disease as an example of coding trinucleotide repeat disorder and Fragile X Syndrome as an example of non-coding trinucleotide repeat disorder, this work will explore the nature of this devastating group of diseases and the underlying basic molecular processes that construct them. Despite sharing key characteristics, these diseases differ significantly in the wide variety of havoc the repeat expansions can create depending on their location and the nature of the disrupted function. Understanding of the mechanism and specifics of each individual disease remains critical for development of proper therapies.
Diverse Mechanisms of Trinucleotide Repeat Disorders: An Exploration of Fragile X Syndrome and Huntington’s Disease.
Undergraduate Review, 9, 151-156.
Available at: http://vc.bridgew.edu/undergrad_rev/vol9/iss1/30
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