Dr. Sher's Advice about Day 3 CGH Testing

[nuthinbutpink]

So, I went on Dr. Sher's blog and posted a comment to him about the 2 opposites and the use of day 3 CGH that apparently caused them. Here is his response:

"I have repeatedly cautioned that day-3 array CGH (aCGH) is fraught with issues. This probably proves my point. The amount of DNA in a single cell is so minute that you aCGH is unreliable. Metaphase CGH done correctly would not make such an error. I urge you to read the blog I posted elsewhere on this site, comparing mCGH with aCGH for PGD. FISH should be accurate but it does not access all chromosomes so, while gender determination would be reliably, assessment of embryo quality falls far short of the mark."

Geoff Sher

So, PLEASE make sure that you NEVER use day 3 aCGH for GS purposes.

[Dr. Potter]

So, I went on Dr. Sher's blog and posted a comment to him about the 2 opposites and the use of day 3 CGH that apparently caused them. Here is his response:

"I have repeatedly cautioned that day-3 array CGH (aCGH) is fraught with issues. This probably proves my point. The amount of DNA in a single cell is so minute that you aCGH is unreliable. Metaphase CGH done correctly would not make such an error. I urge you to read the blog I posted elsewhere on this site, comparing mCGH with aCGH for PGD. FISH should be accurate but it does not access all chromosomes so, while gender determination would be reliably, assessment of embryo quality falls far short of the mark."

Geoff Sher

So, PLEASE make sure that you NEVER use day 3 aCGH for GS purposes.

I have been saying this for some time as well. That is why the aCGH programs have been pushing day 5 biopsy so much. Sher is the first to come out and actually admit that the technology is not good for day 3. GSN with day 3 is equivalent to aCGH on day 5 in terms of accuracy but gives more information.

[nuthinbutpink]

I have been saying this for some time as well. That is why the aCGH programs have been pushing day 5 biopsy so much. Sher is the first to come out and actually admit that the technology is not good for day 3. GSN with day 3 is equivalent to aCGH on day 5 in terms of accuracy but gives more information.

I'm glad you saw this and posted. So, how is day 3 GSN testing different from day 3 aCGH testing in terms we can understand?

[GT77]

How do you feel about testing for FSH on 3day for just PGD?

[Dr. Potter]

FISH is very accurate for gender but as said above does not give you any information about whether the embryo is good or not. It therefore does not help with embryo selection and does not not improve pregnancy rates as 24 chromosome (both aCGH and Natera) testing does. Only Natera (GSN) is able to take the small amount of DNA in a single cell (day 3) and accurately determine the presence of all chromosomes. This is because of the proprietary technology that uses the parental haplotypes to analyze the data from the amplification of DNA from a single cell. aCGH has a difficult time with the small chromosomes (one of which is the Y chromosome another is 21) and so is not great on day three. This issue is mitigated with a day five sample that has multiple cells and therefore more DNA. Natera is the only technology, day 3 or day 5, that is able to detect uniparental disomy (eg Prader-Willi and other 'imprinting' disorders), triploidy (69 chromosomes), deletion/duplication errors and determine whether a bad embryo is from bad sperm or bad eggs. That is why (along with the average implantation rate of 72% with a single embryo) I feel Natera is the way to go.

[girlygirrl]

Dr. Potter, do you believe it is significantly better to do Natera day 3 vs. day 5? Why would you choose one over the other? Thanks!

[Petitepuce]

Dr Potter,

I read somewhere that you are not using Natera anymore and had to switch with aCGH on day 5.
Could you please tell me if, regarding you, aCGH day 5 is totally accurate for gender selection?

Thanks in advance.
Petitepuce