Why is it that the onset age for HD is related to whether its a paternal or maternal transmission? Does anyone have any links that i can read regarding this issue? Thanks.

I don't have a link - I am sure someone else will post one. There are statistics regarding CAG expansion, contraction and staying the same. The percentage of CAG expansion is much higher when it is passed paternally. Higher CAG # is related to earlier onset...

Here is the latest article about repeat instability. As you can see, we still don't have our table formatting just right, but the content is there.

[www.hdlf.org]

Thanks hope and marsha!

So, it looks like Mother to Daughter and Father to Son had the more favorable outcome as far as CAG count is concerned? This is all Greek to me, so I might be inferring the complete wrong thing but it seems that according to this study, if you have to have HD, it's best to be a daughter getting it from mom, then son from dad, and so on and so on.

If that's true, I wonder if that's why my dad had a later onset than my aunt, and then why her son had the earliest onset of everyone so far

All the CAG count study results are based on group averages. Individual cases vary widely because of environmental and other genetic factors. This is why on average CAG count are negatively correlated with age of onset (the higher the count, the earlier the onset) and yet two people with the same count can have onsets more than twenty years apart.

I meant to say something about this..... if you are wondering what it means to you personally (for prediction or planning)... it means nothing. It could have research applications someday. It also dispels incorrect advice we get from health professionals who speak about what they don't know anything about. They will say something like HD is always worse from the father... or always the same from the mother. So understanding a little bit about CAG statistics keeps you from being unrealistically scared or over confident.