Final answer:
Huntington's disease is associated with the huntingtin gene, which contains 36-39 CAG trinucleotide repeats. The repeats lead to the production of a mutant protein that causes neurodegeneration. The length of the repeats is used to diagnose the disease.
Step-by-step explanation:
The huntingtin gene is associated with Huntington's disease, a neurological disorder that leads to the gradual degeneration of the nervous system. The huntingtin gene carries a repetitive DNA sequence known as CAG trinucleotide repeats.
In individuals affected by Huntington's disease, there are typically 36-39 repeats of the CAG sequence in the huntingtin gene. These repeats result in the production of a mutant huntingtin protein, which accumulates in the brain cells and causes neurodegeneration.
As the number of CAG repeats increases, the age of onset and severity of Huntington's disease symptoms tend to worsen. Therefore, the length of the CAG repeats in the huntingtin gene is used as a diagnostic marker for the disease.