I think there are such cases. But more than that I think many people, even though they show some signs earlier, aren't aware that they have HD until later. This was the case with my father, who had only minor chorea and his mental health wasn't too good, but no one thought he had HD until after age 65, when it progressed more rapidly to his death at 73. I'm a writer, too, and wrote a youth novel in which Huntington's Disease is the main problem in the family.