Re: seeking feedback on DNA blood test

[Guest guest]

Steve

My take on this is that they will be looking for the known defects in your

blood which are only a few out of hundreds. You might want to ask how many

mito defects they will be testing for and if they are nuclear or

mitochondrial DNA tests. Please don't let them tell you that you don't have

mito if these tests are negative.

You might also want to ask what they will be looking for with the EMG. There

are single fiber EMGs that take longer, as they work to isolate a single

fiber in the muscle. As far as I know, they can detect a myopathy or

neuropathy and if done as a pre and post exercise test, they can determine

if it is a metabolic myopathy. Again, a negative test doesn't prove you

don't have mito. I have had both positive and negative EMGs done by the same

neuro that teaches EMGs as a speciality for neuro fellows.

You might also want to ask how many mito cases have been determined by the

testing they want to do.

Sometimes you have to go along with some testing to rule out things before

the next step is taken. This is often required by insurance companies. You

might also want to ask " what is next if these tests are negative " .

Good luck!

laurie

>

> Reply-To:

> Date: Sat, 6 Nov 2004 02:43:35 -0500

> To: >

> Subject: seeking feedback on DNA blood test

>

> I've finally received a callback from my " neurologist with apparent interest

> in mito " at MGH. His office left a message about the test they want to do,

> so I wasn't able to ask any questions yet. BTW I had NO idea how many calls

> and delays would be required, before I could get this simple next step

> rolling.

>

> What they want to do, they called it " mitochondrial myopathy DNA evaluation "

> and then said this is " blood work " . I have a definite diagnosis of MSL

> which is known to have mito origins (and for which SOME patients have

> various KNOWN particular mtDNA mutations). I have not yet had any DNA tests

> or biopsies. FWIW they also want to do an EMG (presumably far more involved

> than one I had three years ago).

>

> Before I call them back on Monday to schedule this test, does anyone have

> any specific questions I should ask, or " suggestions " as to which specific

> DNA tests should be done, or preferred labs to do the testing (I think they

> do at least some of this in-house, but I don't really know)? I have the

> feeling that I will have little input on any of this, but it's worth a try.

> Presumably the results may lead to further testing.

>

> Thanks in advance

> Steve D.

>

>

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>

[Guest guest]

I can just add a few tidbits to Laurie's advice. I've had mtDNA and

nDNA screening and also worked with researchers who are very

involved in this field.

First, you will probably have very little input into where your DNA

testing is sent. Most experts have their networks well-established

and only work with certain labs. The testing you receive will be

limited by the testing available at the particular lab where your

sample is sent. There are very few labs that actually test for every

known mtDNA mutation. It takes many man hours to set up protocols

and procedures to test for any given mutation. The availability of

funds and trained personel limit what a single lab can offer. In

addition to the limitations of what one lab can offer, DNA screening

is so expensive that it is often limited to those mutations that may

be most likely given the particular patient history. A good lab will

be sent a patient history and they will try to match that with

likely mutations.

Beyond screening for known mutations, I have also had my entire

mtDNA sequenced, base pair by base pair. This was done on a research-

only basis and doesn't happen unless some researcher gets really

interested in your case and wants to crack it, so to speak, usually

for the purpose of publication and career advancement. If you are

interested in that kind of ultimate mtDNA screening, I would suggest

that you use every opportunity to develop relationships with

researchers. And then be very patient. It might just happen.

As for questions to ask, I would personally want to know which lab

will be doing the screening and which specific mutations (by name)

that you will be screened for. New mutations are being reported

regularly--though I haven't kept up with the mtDNA mutations reports

for the past two years, so not sure just how many are known at this

point, but the number is growing considerably. Just for one mito

disorder, CPT def, there are about 30 different mutations now known,

but most patients with known CPT are screened for only one or two of

the more common mutations.

Congratultions on getting this far. I hope you get some useful

information.

Barbara

> I've finally received a callback from my " neurologist with

apparent interest

> in mito " at MGH. His office left a message about the test they

want to do,

> so I wasn't able to ask any questions yet. BTW I had NO idea how

many calls

> and delays would be required, before I could get this simple next

step

> rolling.

>

> What they want to do, they called it " mitochondrial myopathy DNA

evaluation "

> and then said this is " blood work " . I have a definite diagnosis

of MSL

> which is known to have mito origins (and for which SOME patients

have

> various KNOWN particular mtDNA mutations). I have not yet had any

DNA tests

> or biopsies. FWIW they also want to do an EMG (presumably far more

involved

> than one I had three years ago).

>

> Before I call them back on Monday to schedule this test, does

anyone have

> any specific questions I should ask, or " suggestions " as to which

specific

> DNA tests should be done, or preferred labs to do the testing (I

think they

> do at least some of this in-house, but I don't really know)? I

have the

> feeling that I will have little input on any of this, but it's

worth a try.

> Presumably the results may lead to further testing.

>

> Thanks in advance

> Steve D.