Genetic Testing of Embryos

Personalized, highly-advanced care for preimplantation genetic testing

At Columbia University, our team combines exceptional clinical care with the state-of-the art embryology and genetics laboratory techniques, to generate embryos and identify the ones with the correct number of chromosomes, or test for specific genetic conditions before the embryos are implanted.

In every cell in our body, we have 23 pairs of chromosomes. Chromosomes contain our genetic information – the blueprint for how our cells function – written in a four-letter code (“A”, “T”, “C”, and “G”). Having an extra or missing chromosome is called “aneuploidy.” Down syndrome is an example of an aneuploidy that many people are familiar, where the individual is born with three copies of chromosome 21. An embryo with a chromosomal imbalance will either stop developing, result in miscarriage, or present with major birth defects. In addition to having the wrong number of chromosomes, there can be problems within the chromosomes themselves. For example, a change in one of the letters of the genetic code can result in a genetic disease such as Tay Sachs or cystic fibrosis, while having too many letters in a particular code can result in a disease like Huntington’s disease. 

For more information on preimplantation genetic testing (PGT) and specific conditions, see below.

Pre-Implantation Genetic Testing for Aneuploidy (PGT-A)

Chromosomal abnormalities are responsible for a large proportion of miscarriages and congenital anomalies. With PGT-A, a complete chromosomal analysis of each embryo is conducted. The purpose of PGT-A is to select embryos with the highest implantation potential and reduce the emotional and physical trauma from a pregnancy loss or termination, or risk having a baby affected by an aneuploidy such as Turner’s syndrome or Down syndrome. PGT-A also helps reduce the number of embryos needed to achieve a successful pregnancy, thereby reducing the risk of higher order multiples such as triplets.

You may consider PGT-A if you decided to pursue IVF for fertility preservation, have trouble conceiving or experience pregnancy losses. We recommend that you discuss whether PGT-A is the right decision for you with your physician during your consultation.

Pre-Implantation Genetic Testing for Monogenic Diseases (PGT-M)

PGT-M is the appropriate test for couples whose offspring are at risk for inheriting a single gene disorder. The M stands for monogenic, meaning a disease resulting from a mutation in a single gene. This test can effectively identify embryos affected with a specific inheritable condition. For families with this risk, PGT-M has been utilized and successful for hundreds of different conditions.

You may consider PGT-M :

  • If you and your partner are carriers of common autosomal recessive conditions: In an autosomal recessive disorder, two changed copies of a gene, one from mom and one from dad, are inherited. Carriers of autosomal recessive conditions don't exhibit symptoms and most don't have a family history of the condition. Traditionally, couples learned about their carrier status after having a pregnancy or affected child with the single-gene condition. Nowadays, a simple blood or saliva test can screen the DNA of the couple pre-pregnancy for hundreds of conditions. Some examples of autosomal recessive conditions are: Cystic fibrosis, Sickle cell disease, or Tay-Sachs.
  • If you are a carrier of an X-linked condition: The gene causing the disorder is located on the X chromosome and the sons of carrier mothers are at risk of being affected. Examples of X-linked conditions are: Fragile X, Duchenne Muscular Dystrophy, or Adrenoleukodystrophy.
  • If you or your partner are from a family with a certain inherited neurological disorder: Reproductive age members of families with neurogenetic conditions are typically interested in prevention of transmission to children and grandchildren sometimes without knowing their own carrier status. The majority of the inheritable neurodegenerative disorders are autosomal dominant; passing on one changed copy of a gene may result in symptoms related to the condition. Nondisclosure testing can be utilized to identify the embryos at risk without testing the parents.  Examples of heritable neurological conditions are: Early onset Alzheimer, Huntington Disease,  and Familial ALS.
  • If you or your partner have inheritable cardiac or renal disease: Most of these conditions are autosomal dominant in inheritance and may be associated with sudden death or need for kidney transplant at young age. Examples include Long QT syndrome, cardiomyopathy, Marfan Syndrome, and Adult Polycystic Kidney Disease.
  • If you or your partner have a cancer predisposition gene: Most of the cancer predisposition syndromes are inherited in autosomal dominant fashion. Some examples of hereditary cancer genes that are frequently subject to PGT-M are: BRCA, Lynch, Familial adenomatous polyposis.

PGT-M can be performed for multiple conditions at the same time. PGT-M, PGT-SR, or PGT-HLA testing is usually conducted along with PGT-A so that we know that the embryo is free of the genetic disease for which the couple is at risk, as well as having the right number of chromosomes. If indicated, PGT-M, PGT-SR and PGT-HLA tests can be performed in conjunction.

Preimplantation Genetic Testing for Chromosomal Structural Rearrangements (PGT-SR)

Many carriers of balanced chromosome rearrangements are healthy, however they are at risk of  having multiple miscarriages or having a child with mental and physical disabilities. Embryos generated with IVF can be tested with PGT-SR to achieve a pregnancy with chromosomally correct embryos. Translocations occur when segments of two chromosomes break off and change places. Inversions are a result of a segment of a chromosome being in the reversed orientation. You may consider PGT-SR if you or your partner are carriers of a balanced translocation or inversion.

PGT-M, PGT-SR, or PGT-HLA testing is usually conducted along with PGT-A so that we know that the embryo is free of the genetic disease for which the couple is at risk, as well as having the right number of chromosomes. If indicated, PGT-M, PGT-SR and PGT-HLA tests can be performed in conjunction. 

PGT for Human Leukocyte Antigen Match (PGT-HLA)

You may consider, PGT-HLA if your child has a blood disorder or immunodeficiency and allogeneic bone marrow/stem cell transplantaion is recommended by his/her physician. IVF will be performed to select the embryo suitable for donation.  Cord blood from immunologically matched sibling at the time of birth can be used to treat your sick child.   

PGT-M, PGT-SR, or PGT-HLA testing is usually conducted along with PGT-A so that we know that the embryo is free of the genetic disease for which the couple is at risk, as well as having the right number of chromosomes. If indicated, PGT-M, PGT-SR and PGT-HLA tests can be performed in conjunction.