PGD-PCR possible outcomes
No embryo transfer
Not all embryos may be suitable for biopsy. They may however, be suitable for freezing or untested transfer .
An answer is achieved for most of the embryos tested. If for technical reasons we do not get an answer on an individual embryo, the genetic status of that embryo will be considered as unknown. These embryos may still be suitable for clinical use.
No embryos with desired genetics
Embryos tested and deemed abnormal or affected are unsuitable for transfer.
You may complete a cycle and not have an embryo suitable for transfer.
Whilst we take stringent precautions to avoid DNA contamination, there is always a small risk that this may occur and could result in a misdiagnosis. PCR will copy any DNA and any contamination present will contribute to the answer.
Misdiagnosis – technical factors
Other technical factors may contribute to loss of genetic information that might result in misinterpretation of the genetic status of the embryo.
Technical limitations can also lead to a reduction in test accuracy. If this occurs during your treatment it will be discussed with you by your PGD scientist.
Preferential Amplification and Allele Drop-out
DNA may copy unevenly which could cause difficulty in interpreting the results for certain linkage markers. This is why the ‘DNA fingerprint’ looks at multiple regions around the gene.
Chromosomes naturally rearrange their DNA during egg and sperm formation and this may affect the interpretation of the result. If a direct mutation test is included, it may help resolve any interpretation problem.