My mom has huntington's disease. my grandmother died with hd. now my mom has it. my mom has five daughters and three son. how many of her children are likely to get hd? and what is their life expectancy after they receive it?
2 doctor answers • 2 doctors weighed in
Radiation Oncology 27 years experience
People : People with hd usually have one normal copy of the hd gene and one disease-causing copy. Unfortunately, the disease causing copy is the "trump card" and causes the disease in people who have it. Parents only pass one their two copies of their genes to each child. This means that there is a 50/50 chance of getting hd for each child of a patient with the disease. In other words, on average half an hd patient's children will get the disease. However, there is a chance (0.39% to be exact) that you and all of your siblings received the normal copy of the gene and will not get the disease.
Very rarely an hd patient can be born with two disease-causing copies of the gene. This can only occur if both of their parents had the disease, so it doesn't sound like this applies to you or your mother. In this situation though, the affected patient can only pass on the disease-causing gene so all of their children will be affected.
There is also something called variable penetrance which basically means the severity of the disease and the time of onset can be different among affected siblings in the same family. Another phenomenon is called genetic anticipation in which the disea gets worse in successive generations. However, this probably doesn't apply to you because it usually happens when the father is the person with the disease and not the mother.
On average, life expectancy is about 20 years after the onset of symptoms.
There are many good resources on the internet (the attached wiki page is quite good), but the best source if information tailored to you would be to meet with a certified genetic counselor or medical geneticist. Your primary doctor should be able to get you in touch with one in your area. They can also talk to you about genetic testing for the disease although most people at risk don't seem to take the test.
There is more and more research in the area and hopefully an effective treatment will be available in our lifetimes. I also attached a link to the hd society of america whic is a support organization that may be helpful for you and your family.
I wish you and your siblings the best of luck.
5.3k viewsAnswered >2 years ago
Developmental and Behavioral Pediatrics 51 years experience
Each child has 50% r: Each of your mom's children has a 50% chance of having inherited the huntington gene. They can be tested to see if they have. Symptoms may or may not have appeared depending on their age, but genetic testing can be done before they develop symptoms. How long they will live after developing hd depends on how old they are when they develop symptoms and what the range of disease progression has been.
5.3k viewsAnswered >2 years ago
Last updated Oct 3, 2016
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