[tri-med] Re: question regarding genetic tests: Cells counted etc

----- Original Message ----- 
From: "Barbara Farlow"
> I think that you are the smartest non-geneticist on trisomy in the world. 
> I cannot believe how much you know. Thanks so much for this review.

Nope just had to learn the hard way - still earning my degree in Alex:-)

> To compare my tests with yours: (done with cord blood)
> G Banding resolution: 450
> Cultures: No mention of cultures anywhere
> Cells Counted 12
> Cells Analyzed 5
> Karyotypes 2
>
> We had specifically asked that the karyotying test be stopped. FiSH had 
> revealed the existence of tri 13 and we saw no benefit in the full test. 
> As Annie seemed to be mildly afflicted, we believe that in the absence of 
> the karyotpying test, they might assume that she was mosaic and not give 
> up on her so easily...or at least treat her for herself and not the 
> genetic label. >>

Thats always the hope and why I believe screening and testing should only be 
offered when the parents know the consequences.

> The geneticist assured us that the results would be kept in the genetics 
> office of a different hospital and they would not be revealed without our 
> express consent. Guess what? They lied. We learned after death that the 
> results were sent directly to the children's hospital.

Aaaah in many cases legally, even though they told you that they do not have 
to abide by it because they can share anything that they consider to be in 
the patients interest with a collegue or member of the team. The geneticist 
actually has no right to tell the lab what to do. There are exceptions but 
it falls into legal technicalities and thats nightmare time. We may make 
jokes about lawyers but having worked side by side with some for a long time 
now I have to admire them their jobs arent always easy.......... a word, a 
comma can change everything and its always up to "interpretation" of the 
law.

> I guess my question is how certain can I be about the chance of mosaicism, 
> or not?

If the FISH showed mosaicism then I would accept that (personally) - legally 
its the g-banding though FISH would be considered. My personal cautions on 
that are - it depends on when the FISH was done. FISH is new, it was only 
introduced in the late 90's and not widely done for 5 years after that. So 
its only been around for 10 years or so and most labs have been doing it for 
less than that. The pertinent questions are how long had the lab been doing 
FISH testing, what probe did they use and how experienced was the technician 
and how many checks are done in the lab. We have three labs in Sydney and 
there is one that I will not use as I have never had an accurate result from 
them.

Trisomy 13 is actually a little more complicated than 18 or many of the 
others because its a Robertsonian chromosome - meaning that you don't need a 
whole chromosome to have a "full" trisomy only the q arm.

It's actually too late to do any retest as the tissue has to be "live". That 
was the problem with the urine specimen we used. It was sent out of state 
for independent testing and although it was refrigerated during collection, 
spun off and couriered to the lab within 12 hours it was too "dead" to grow 
properly.

DNA testing is an option but it wont pick up mosaicism and you would need to 
find someone willing to work outside the box. Meaning that its theoretically 
possible but as far as we know never been done.

If the original g-banding slides were kept you might be able to double check 
but they are preserved and that causes them to degrade fairly rapidly. Ours 
were re-examined 15 months after they were made but they were too degraded 
to see anything. DNA testing may have been possible to confirm that it was 
actually Alex's blood but not for the trisomy. The trisomy would only have 
shown up by confirming that there was two sets of maternal or paternal 
originating DNA - not conclusive but an indication of trisomy not mosaicism. 
And not back then (1994) as the science wasnt advanced enough. It is now but 
the slides have mysteriously disappeared even though they were supposed to 
be secured as "evidence".

So I guess I am saying you will have to go with what you have - and if it 
were me the FISH would give you the better answers. That it was cord blood 
is good. Blood tests two embryonic lines, skin only one. Did they test again 
after birth?

> By the way, my essay about Annie's life was accepted by a major bioethics 
> journal for publication some time in the next few months.

Thats great!! As it now appears we are definitely going to court I have been 
working on my book in my spare time. Its not moving very fast because I 
don't have a lot of spare time and its both confronting and painful to 
relive it all on a personal level instead of a detached scientific level.

Life consists not in holding good cards but in playing those you hold well.
                                            -- Josh Billings

Keep Looking For Rainbows!!
   _--_|\
 /Karen \
 \ _.--._ /
          v Karen, Mum to Alex (14 years, T-18 Mosaic)
http://members.optushome.com.au/karens

                  Building ___ooOOoo__ Rainbows
                       www.trisomyonline.org
                  Families Helping Families On-line

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