Predictive Testing for Huntington's Disease

pyropath

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I have a character who just lost his father to Huntington's, and is debating on whether or not he wants to find out if he's going to develop the disease later in life. He eventually decides he does want to find out and opts to go through with the genetic predictive testing.
I was just wondering how exactly that testing occurs. I've seen a lot online about before and after the test, coping with results and such, but I haven't seen anything about how they actually run the test.
Does anyone have any information that might help?
 
Pyekett

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There will be meeting(s) with a genetic counselor first. This is a highly--hmmm, "regulated" isn't the right word, but it's close enough--regulated area of genetics, and the protocols are both clear and thorough. [I see you found some discussion of the "coping" process online.]

Are you interested in [more about] the encounter-by-encounter experience a character would have in seeking out and obtaining the information, or the laboratory details of how it is done, or both?
 

pyropath

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Pyekett said:
There will be meeting(s) with a genetic counselor first. This is a highly--hmmm, "regulated" isn't the right word, but it's close enough--regulated area of genetics, and the protocols are both clear and thorough. [I see you found some discussion of the "coping" process online.]

Are you interested in [more about] the encounter-by-encounter experience a character would have in seeking out and obtaining the information, or the laboratory details of how it is done, or both?
Click to expand...

I'm more interested in what this character will personally go through throughout the process of finding out the results. Like, what will they have to do to him in order to take a DNA test and what is that procedure like?
 
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Ah. That's just a blood draw just like any other.

For most places, once the genetic counseling has been completed, you take the lab requisition slip to a given laboratory. You either wait in line or are taken to a seat, made comfortable, and asked to roll up your sleeve. You are asked to clench a fist, a vein in in your arm is selected, and the skin over it is cleaned. You are asked to relax your fist and hold still. One or more tubes is connected to the needle setup sticking out of the vein, and the blood is drawn (often by internal vacuum) into the tube(s). Then the tourniquet is snapped off and the needle withdrawn while pushing a cotton ball down on the site to stop bleeding. Often you are asked to press the cotton down for a few minutes to prevent bruising. The ball is removed and a bandage placed, or a bandage or medical tape may be placed over the ball to hold a little additional extended pressure. Usually there is a reminder that your physician will talk to you about the results, and then you are free to go.

Added: Cheek (buccal) swabs are available for some genetic testing, but I don't think the tech is there yet for HD [in a reliable way]. Even if it is, most testing for it would still be standard blood draw, so that would fit okay for your story. I'll look around and see if I can find a buccal HD test, anyway.
 
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Pyekett

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The Huntington Disease Society of America does not have any information about buccal testing on their website that I can find. They do have information about PCR and Southern blot tests on standard blood draw DNA samples.

Additionally, the HDSA has a protocol which most testing centers follow. It is available (2003 version) here as pdf: http://www.hdsa.org/images/content/1/1/11884.pdf

You might find the Section 4/B/5 particularly useful, titled The predictive testing process: "The components of predictive testing are shown in Table 1 and described in detail on page 22."

1. Initial telephone contact
2. Neurological evaluation
3. Genetic counseling
4. Documentation of informed consent
5. Psychological assessment
6. Review of the potential impact of the test
7. Disclosure of results in person
8. Follow-up after testing
 

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Pyekett said:
Ah. That's just a blood draw just like any other.

For most places, once the genetic counseling has been completed, you take the lab requisition slip to a given laboratory. You either wait in line or are taken to a seat, made comfortable, and asked to roll up your sleeve. You are asked to clench a fist, a vein in in your arm is selected, and the skin over it is cleaned. You are asked to relax your fist and hold still. One or more tubes is connected to the needle setup sticking out of the vein, and the blood is drawn (often by internal vacuum) into the tube(s). Then the tourniquet is snapped off and the needle withdrawn while pushing a cotton ball down on the site to stop bleeding. Often you are asked to press the cotton down for a few minutes to prevent bruising. The ball is removed and a bandage placed, or a bandage or medical tape may be placed over the ball to hold a little additional extended pressure. Usually there is a reminder that your physician will talk to you about the results, and then you are free to go.

Added: Cheek (buccal) swabs are available for some genetic testing, but I don't think the tech is there yet for HD [in a reliable way]. Even if it is, most testing for it would still be standard blood draw, so that would fit okay for your story. I'll look around and see if I can find a buccal HD test, anyway.
Click to expand...

Thank you! this is all very helpful!
 
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