Criteria For JHD vs HD

I've seen a couple different versions of the data criteria for determining whether or not a patient is considered JHD.  My daughter was diagnosed before age 20 and has a repeat number of 69 so was clearly diagnosed as JHD.  My son, however, was told his is adult onset originally but the neurologist he sees now said with a repeat of 55 (50 or more) and symptoms beginning in early twenties, he is JHD as well.  Not that this makes much difference as we still cannot stop this beast in its tracks, but it's interesting to know from this standpoint:  HD is rare, JHD is more rare, and with the small number of JHD patients in one state, for instance, we have two of them.  And even though they are siblings, only two years apart, their symptoms are most definitely not the same.

I'm interested in finding out if others see very different symptoms among close siblings.