Review Question - QID 106278

A 31-year-old presents with self-described complaints of being "fidgety and irritable" that is unlike his "calm personality a few years ago". What is concerning to him is that his father was diagnosed with a similar condition at the age of 38. His father began a progressive decline - losing interest in his life and family, becoming messy, experiencing involuntary movements, and worsening dementia as he grew older. Genetic tests were performed on the patient which confirmed that he has a larger number of repeats than his father. He is concerned that the disease may begin earlier for him or may have already started. Which of the following trinucleotide repeats is found in this disease?