A 30yearold woman comes for genetic counseling to discuss her recent presymptomatic testing for Huntington disease (HD), which was negative. Her mother was diagnosed with HD at age 36, and her deceased maternal grandmother was diagnosed with HD at age 40. Neither had DNA testing. Which of the following is MOST important to discuss with the woman?
A. Confirmatory DNA testing of her mother is needed.
B. Her mother and grandmother did not have HD.
C. She could still develop HD because of anticipation. D. She did not inherit the familial condition.