Preimplantation Genetic Testing (PGT)

Preimplantation genetic testing (PGT) is a test that is performed on embryos in the laboratory 5 or 6 days after egg retrieval. A small sample from appropriately developed embryos is removed for the purposes of testing. The chromosomal information obtained in the PGT results indicate chromosome abnormalities such as Down syndrome or other chromosomal abnormalities that can often lead to miscarriage. The results also indicate whether the embryo is male or female. Patients at risk for a child with a genetic disorder can use PGT-M to select embryos that will not be affected.

Yes. Data from many years of PGT following embryo biopsy indicate that adding PGT to an IVF cycle does not lead to an increase in genetic or chromosomal disorders as compared to an IVF cycle that does include PGT. Removal of a few cells of the early embryo does not alter the ability of that embryo to develop into a complete, normal pregnancy.

PGT-M (monogenic) is possible for almost all monogenetic genes if prior testing has identified the underlying genetic change(s) and if there is clear data to support the cause of the disease in the family. Genetics & IVF Institute has long been a leader in PGT for genetic disease prevention. Following a consultation with our reproductive geneticist, a PGT-M test is custom developed for the patient in advance of the IVF cycle so that once embryos are available, testing of the embryos can determine which embryos are unaffected, affected, or depending on the disease, a silent carrier of the specific disease in the family. In addition to PGT-M for autosomal dominant, autosomal recessive, and X-linked disorders, PGT-M for cancer predisposition genes is routinely performed.

Genetics & IVF Institute is a pioneer in non-disclosing PGT for Huntington’s disease (HD), which still benefits parents today, as noted in this article highlighting a grateful mother and past GIVF patient. Many patients with a family history of Huntington’s disease want to prevent having a child who will develop HD. Often, people do not know if they have HD when they are family planning because the average age of onset of clinical symptoms is approximately 40 years old. These patients may want to prevent having a child with HD but also do not want to know if they carry the HD gene. Non-disclosing PGT for Huntington’s disease can help decrease the chance of conceiving a pregnancy with HD while not identifying the HD status of the parents. PGT for Huntington’s disease is also available when patients already know their HD status and wish to prevent transmission to the next generation.

Yes, PGT-A (aneuploidy) will identify which embryos are male and which embryos are female, in addition to screening the embryos for chromosome abnormalities (aneuploidy). If there is a preference for either sex, the PGT-A result will aid in embryo selection or the order in which embryos are selected for transfer. Patients are encouraged to discuss their embryo transfer options with their physician.

Yes. PGT-A is performed in addition to PGT-SR (structural rearrangements) or PGT-M, and for patients at risk for more than one disease, PGT-M for multiple diseases can be done. In addition to the known genetic diseases, biopsied embryos are screened for chromosomal aneuploidy. Only embryos unaffected by the genetic disease and with a normal chromosome result would be considered for transfer. Whether to use or not use embryos that are carriers of an autosomal recessive or X-linked disease will be discussed with each patient. The combination of PGT-M for genetic disease, and PGT-A for aneuploidy screening, will help identify the best embryo(s) to use with the greatest chance for a healthy outcome.