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Trinucleotide Repeats

Meaning

Trinucleotide repeats are a specific type of genetic sequence characterized by the tandem repetition of three DNA base pairs, such as cytosine-adenine-guanine (CAG), which can occur within the coding or non-coding regions of a gene. The number of these repeats is typically stable but can expand beyond a normal threshold during DNA replication, a phenomenon known as trinucleotide repeat expansion. Clinically, this expansion is the underlying genetic cause of a number of neurodegenerative and neuromuscular disorders, with the length of the repeat often correlating with the severity and age of onset of the disease. This is a critical factor in genetic predisposition.