Chromosomal abnormalities in embryos may cause implantation failures and miscarriages
CGH technique which is the newest PGD technqiue which looks at all chromosomes of the embryos. Humans have 46 chromozomes. Therefore its much more developed technique. Fisch technique PGD on the hand looks only at 5 chromozomes. CGH gives a better understanding of genetically healthy embryos compared to the Fish Technique
The disadvantage is that the CGH is priced per embryo and the analysis is still expensive. CGH is requires the embryos to be frozen. We do the CGH and freeze the embryos 5-6 days after the egg collection. It takes about 2-3 weeks for the results to come. The patient needs to come back to the clinic for a frozen embryo transfer.
This technique is useful for couples who had multiple IVF failures or miscarriages.
Below you can see the report of 2 cases done with Array CGH. On the X axis you see the chromosome numbers starting from 1 to 22 and then you see the X and Y chromosomes.
The first graphich shows the compatibility of an embryo sample to a normal female DNA. The second one shows the compatibility of the same embryo to a male DNA. This is done in such a way because we cannot know the gender of the embryos at the beginning. The red moving line shows anomalie at the 4th chromozome and therefore there is a blue box which lies above of the red line. This indicates that chromosome 4 has extended itself and it causes Trysomy, meaning that the chromoze 4 extended from being 2 DNA’s to 3 DNA’s. An embryo with 3 DNA of the same chromosome is considered abnormal.
At the end of the graph we also see that X chromozome is below the red line and Y chromosome is above the red line. This is however normal now because as mentioned, this is a compatibility test of an embryo to a female embryo which has XX chrmomozes. Male embryo has XY chromozome. This particular embryo is a male embryo because it has 1 less X chromosome and 1 extra chromozome of Y. In the second graph we see the peformance of the same embryo to a male DNA. There we still see the problem on Chromsome 4 but we dont see a problem at the end of the Graph where the X and Y chromozomes are. Since it came normal we understand that this embryo is a male embryo .
On the third and fourth graphics we see normal male embryo graphic . There is no chromosomal abnormality