Huntington's Disease Cag Repeat Age Of Onset Chart. About 10% have onset of motor symptoms after age 60 and 10%. Knowledge of the typical age of onset sometimes leads physicians to miss the diagnosis, mistakenly believing the person to be too old or too young to develop hd.

Knowledge of the typical age of onset sometimes leads physicians to miss the diagnosis, mistakenly believing the person to be too old or too young to develop hd. While most people with hd develop the motor symptoms in their forties and fifties, subtle changes may arise much earlier. About 10% have onset of motor symptoms after age 60 and 10%.