genetic testing

[kme]

I am considering asking our ped for some genetic testing for my son. When we were at Kennedy Krieger, they mentioned mitochondrial testing too.

How do I go about asking for this? Do I have to ask for specific disorders to be tested for or can they just run a test and see what "pops" up? At this point I am mostly interested in Fragile X and also a test to see if he has the right number of chromosomes.

I don't understand mitochondrial testing at all - what do I ask for?

How do you know genetic testing is warranted?

My son is just such an enigma and does have some "unusual" (although I think endearing) physical features like large ears (Fragile X).

Thanks for any info you can share.

[2boyzmama]

My understanding is that it used to be that the drs had to have some specific things in mine when testing, but now there's a test called a Microarray that tests all 46 chromosomes simultaneously. That's the test that my son had that found his deletion. He had a chromosomal analysis done initially that missed the deletion, but the Microarray found it.

As for the mito stuff...I know very little...but others do who will hopefully be by to asnwer that part. I believe it involves a biopsy...

[askew]

I think your family doc can order a chromosome analysis. This is easy, and just a blood test and a two week or less wait. If that does not show anything (although fragile X would show up) you can ask for the microarray. My insurance won't cover it. I have tried 3 times. Which is something to consider as the test is like 5K. It also takes a lot longer to get results. Like 8 weeks I think? So I would ask for the simple chromosome analysis first, and if it turns up nothing you can ask for the fancier in depth test.

I know nothing about Mito stuff, but someone who does will certainly pop in soon.

[mrsfru]

Personally, I would wonder if the answers to the tests are worth it, if you don't have someone who knows how to interpret them. I'd look into a geneticist. DS has an appt w/one in June. Our insurance will cover it, but maybe for some, they'd cover none or would only cover it if your ped did it.

GL!

mrsfru

[kittynurse]

I'm in Canada so I don't know how helpful my info will be but for DS1 we have 2 separate requisitions - 1 just for Fragile X and then 1 for chromosomes. Our Dev Ped is specifically looking to rule in/out Fragile X so that may be why it's separate? I don't know. It also goes to a different lab than the chromosome analysis.

HTH

Martha

[sbgrace]

I don't know about genetics. I do know about mito (that would be metabolics). The tricky part of testing for mito is 1. there are very few doctors who understand enough to test and interpret accurately; depending on your location you might be lucky and have one near but most people need to travel
2. The initial testing is blood (lots of it) and urine. But that isn't diagnostic right now. If they find markers in those tests you move up to muscle biopsy for actual diagnosis. We didn't go that far because it wasn't going to change our treatment (we did do a skin biopsy). There may be better, less invasive tests on the horizon and I'm holding out for that for my kiddo. He is under treatment though (his blood/urine/and skin were abnormal and we ruled out everything else to explain those abnormalities). Metametrix urine isn't a metabolic test but that company runs a lot of metabolic labs. It caught all the stuff the metabolic testing we did do found in my son and recommended the same treatments.
My link about mito:
http://www.mothering.com/discussions...d.php?t=734501

umdf site with testing information:http://www.umdf.org/site/c.otJVJ7MMI..._Diagnosis.htm The top one/metabolic screening in blood and urine are the initial tests run at least in my experience (two different mito centers/doctors).

treatment information: http://www.umdf.org/site/c.otJVJ7MMI..._Therapies.htm

Does he have low muscle tone? Fatigue?

[CarrieK]

Your general pediatrician should be able to do the Fragile X test and I don't think it's too costly. Not sure if the pediatrician can do the microarray to check for abnormalities in chromosomes. We had to have the microarray done by a Geneticist. As a PP mentioned, the microarray test is pretty expensive - at least 3-4K - so check with insurance first. If an abnormal result shows in the microarray (as with my son) the parents are usually asked to do the microarray to see if the parents are carriers or if it's unique to the child.

[Lollybrat]

DS had chromosomal testing as part of the diagnostic process for Autism Spectrum Disorder. (I remember that the developmental ped was a little annoyed that I had refused an amnio while pregnant.) They were primarily looking for Fragile X. His chromosomes came back normal.

DS also has albinism, and we would need to have genetic testing done to determine exactly which variant he has, since there are many. The testing for this is only done at a few specific labs throughout the country and is very expensive. Each lab tests for a different specific form, so we would actually need to have a series of tests done. We do want to rule out the forms that involve certain complications (ie bleeding disorders, organ problems). But if DS doesn't have one of those types, then I'm not sure it's really important for us to know the exact genetic defect involved.

Originally Posted by 2boyzmama

My understanding is that it used to be that the drs had to have some specific things in mine when testing, but now there's a test called a Microarray that tests all 46 chromosomes simultaneously. That's the test that my son had that found his deletion. He had a chromosomal analysis done initially that missed the deletion, but the Microarray found it.

2boyzmama - Was Connor's Microarray covered by BCMH?

[2boyzmama]

Originally Posted by Lollybrat

2boyzmama - Was Connor's Microarray covered by BCMH?

Yes, but he was on his diagnostic letter then, not his treatment letter, which might have been why. Also, the lab that did the test paid for myself and my husband to be tested since Connor's test was positive, so we didn't have to pay for ours either.

We were told there were two labs in the country that do the microarray, and that if the first test was normal, we could send another sample to the other lab. I don't know if that's still the case or not...it's been two years. I have a copy of the lab report, I can give the name...I'd have to find it...

[kme]

Thanks for the replies and information!! I will ask his ped about fragile x specifically and ask him his opinion on the other testing. Since Fragile X is my biggest concern right now, maybe just testing for that first is what we should do. I certainly can't afford $5K so I guess I will take it one step at a time!

Thanks again!

[muldey]

All Gabey's tests were done by a geneticist.He had the regular chromosome testing done first,and when that came out normal he had the microarray done which showed a microdeletion on his 2nd chromosome.Exh and I were tested as well,for free.My results came back negative but exh's aren't back yet.Like others have said it is very expensive but hopefully your insurance will pay for it.We had to fight a little,but it was approved fairly quickly.

[MotherWhimsey]

The Mitochondrial testing can be done with a blood test, but it's not going to give difinitive answers in all cases and is very expensive and sometimes hard to get insurance to cover. We did the muscle biopsy first which showed a primary Mitochondrial disease, and then we did the mtDNA testing, which showed all his mutations. We didn't have a hard time getting insurance to cover it (I think probably because he already had the diagnosis based on the muscle biopsy).

The reason it is not always difinitive is that there are some mutations that don't cause symptoms if they occur alone (and some don't cause any at all). But there are a lot of mutations that they haven't seen. My son's primary "causitive" mutation had only been seen once before, and 4 hadn't ever been seen (so in a sense they aren't sure if these are symptomatic mutations or even the causative mutation), and he had 29 that had been seen before, some symptomatic, some secondary mutations, and some that are only symptomatic due to "synergistic effects." Clear as mud?

[Joy*4]

Sorry to respond to such an old post, but I was searching for Fragile X info on here. I'm a new member, so bear with me.

If you are looking to rule out Fragile X, you have to have the CGG count - the count determines whether or not a person is a carrier, has the full syndrome or does not have either one. Chromosome tests on their own won't rule out FX. We had the Chromosome test come back fine, but we tested positive for FX - much to our developmental pediatrician's surprise.