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CAG Repeat Length

Meaning

CAG repeat length refers to the number of times the trinucleotide sequence Cytosine-Adenine-Guanine (CAG) is repeated within a specific gene’s coding region, which is particularly relevant in hormonal and neurological contexts. These repeats code for the amino acid glutamine, forming a polyglutamine tract in the resulting protein. Clinically, variations in this repeat length are a key genetic biomarker, as an abnormally expanded number of repeats is associated with a class of neurodegenerative and endocrine disorders. Assessing this length is a precise genetic test used to gauge androgen receptor sensitivity and determine susceptibility to certain conditions.