My dad only got symptoms at 50, will I get them late as well?
HDYO has more information about HD available for young people, parents and professionals on our site:
Q. My dad starting showing hd symptoms at 50. I carry the gene does this mean I won’t get it until later in my life as well or can I show symptoms young even though his were older?
Mary, Young Adult, Australia
A. Dear Mary,
Thank you for contacting HDYO. You raise a very good question, and one that is unfortunately quite difficult to answer. Having said that, the fact that your dad had not developed symptoms until the age of 50 still gives much more reassurance for you than if he had been in his 20’s or 30’s for example. In other words - while we can’t rule it out, we would be hopeful that your dad’s age at onset means it would be less likely you would have a very early age of onset of symptoms.
The reason that we can’t give a definite answer to your question is because the age at which different people who have the HD gene start to have symptoms can be quite variable. As you probably know, the average age to start with symptoms is around 35-50, but some individuals with HD start to have symptoms earlier or later in life than this. Some of this variability is linked with the size of the HD gene that the individual carries (the ‘CAG’ repeat size – see this HDYO article for more information about CAG repeats), as we know that people who have a larger CAG repeat size can sometimes (but not always) have an earlier age of onset. BUT the repeat size is only half the explanation – so knowing the exact CAG repeat size is not really very helpful in predicting the age of onset of symptoms for any one individual. There is lots of research going on to investigate what other genetic factors, as well as possible lifestyle/environmental factors, modify the age of symptoms, so in the future it may be possible to predict the age of onset of symptoms more accurately.
I’m guessing that you will have had contact with a Genetic Counsellor at some stage during your genetic test process? If so I’m sure that they would be happy to arrange an appointment if you wanted to discuss this subject further with them, and they may be able to look at the information they have about you/your family to see if they can give you any further guidance.
I hope this helps answer your question but please do not hesitate to get back to us if you wish.