CAG Repeat Expansion

CAG repeat expansion is a genetic mutation involving the increase in the number of consecutive CAG DNA sequences within a gene. Normally, this sequence is repeated a certain number of times, but in some disorders, it becomes abnormally long. This expanded segment produces an abnormal protein that can damage nerve cells. Such mutations are linked to diseases like Huntington's disease, where the severity and age of onset often correlate with the number of repeats. The more repeats, the greater the potential for disease development, as the abnormal proteins interfere with normal cell function.