Preimplantation Genetic Testing for Hereditary Conditions

This section focuses on preimplantation genetic testing (PGT) for hereditary conditions, as opposed to preimplantation genetic testing for aneuploidy (PGT-A). If you and/or your partner are at risk of passing on a serious genetic condition to your children, preimplantation genetic testing (PGT), formally named preimplantation genetic diagnosis, can offer a hopeful alternative. By performing DNA testing on embryos and transferring into the uterus only those without the inherited condition, genetic diseases can be prevented – and studies have shown that PGT can provide optimism and peace of mind during pregnancy and after birth.

What is PGT?

PGT (formerly PGD) can be used to identify embryos at risk of having a specific genetic or chromosomal condition.

Patients undergo in vitro fertilization (IVF) to create embryos, and then cells are removed from each embryo for genetic testing. Embryos with normal results are replaced into the uterus in the hopes of achieving pregnancy and delivering a child without the genetic condition.

When is PGT offered?

Patients choose to do IVF with PGT in order to significantly decrease the chance of having a child with a certain genetic or chromosomal condition.

Examples include:

  • A couple has had a previous child or pregnancy with a serious genetic condition;
  • A woman or a man has a serious heritable condition and their children have a 50% risk to inherit the disease gene;
  • A couple learn that they are both healthy carriers of the same recessive genetic disease, often without having any family history of the condition;
  • A woman or man learn that they are carriers of a chromosome change predisposing them to making eggs or sperm with a chromosomal imbalance that increases the risk for miscarriage or birth defects in their pregnancies.

If you are seeking PGT, you may have never had fertility problems. Or, you may have been undergoing a fertility evaluation when genetic testing revealed that you have an increased risk to have a child with a genetic condition. In any case, fertility treatment using IVF is necessary in order to create and test embryos prior to implantation.

Why choose ORM for IVF with PGT?

PGT (formerly PGD) has been performed for over 25 years.

However, most people considering PGT aren’t sure where to start with such a specialized procedure. ORM can help you understand the steps of the PGT process and how they can be customized for you.

Patients from around the globe trust us for their PGT care due to several factors:

  • Our experience:

    Our expert team has performed PGT for a wide variety of inherited pediatric and adult-onset genetic conditions and chromosomal abnormalities using different genetic technologies and protocols.

  • Our clinical team:

    Our incredible physicians and clinical staff provide compassionate and personalized care to patients who may be unfamiliar with the IVF process and what to expect.

  • Our IVF success rates:

    IVF success rates are of paramount importance in the PGT process. ORM’s rates have been in the top 1-3% across all U.S. categories for several years – see our latest IVF statistics here.

  • Our embryology laboratory:

    Having performed biopsies for PGT on over 12,000 embryos since 2010, our embryologists are skilled in the latest biopsy techniques, namely day 5 trophectoderm biopsy. Although the risk of embryo biopsy varies dramatically between programs, at ORM, less than 1/2,000 embryos are not recommended for transfer after the biopsy.

  • The latest genetic technologies:

    Our reference laboratory, CooperGenomics, has performed PGT on tens of thousands of embryos, are continuously investigating new protocols, and regularly present their research at international conferences and in the scientific literature.

  • Genetic counselors:

    The availability of in-house genetic counselors and a Genetic Services Coordinator is a unique aspect of our program – they help our patients understand their genetic risks and options and interface with the PGT laboratory while accompanying patients on their PGT journey.

  • Experience in treating out-of-town patients:

    We understand the unique needs of our patients who travel from afar to see us. Our team is adept at communicating with patients in other cities, states, and countries in a timely manner; facilitating appointments at patients’ local clinics when necessary; coordinating schedules and grouping appointments; and helping with travel arrangements.

  • Support:

    We are fortunate to have a close relationship with the compassionate and professional clinical psychology team Family Building Connections, who has an in-house office at ORM. Their team provides support for our PGT families dealing with the stresses presented by infertility, the impact of a genetic condition on the family, the loss of a parent, child or pregnancy with a genetic disease, and those making reproductive choices

For which diseases can PGT be performed?

PGT (formerly PGD) is available for the vast majority of serious genetic conditions as long as the particular gene mutation or chromosomal condition in the family has been identified through genetic testing.

There are two general categories of conditions for which PGT is offered. There are: preimplantation genetic testing for monosomic/single gene conditions, referred to as PGT-M, and preimplantation genetic testing for structural chromosome rearrangements, which is referred to as PGT-SR.
MONOGENIC/SINGLE-GENE CONDITIONS:

These conditions are caused by DNA mutations in a single gene. One parent may have or carry a heritable genetic disease, or both members of a couple may be healthy carriers of a recessive disease.

Some examples of single-gene conditions for which PGT, formerly PGD, can be done are:

  • Pediatric conditions such as cystic fibrosis, spinal muscular atrophy, thalassemia, and sickle cell anemia;
  • Metabolic disorders such as Tay-Sachs disease and Fanconi anemia;
  • Hereditary cancer syndromes such as breast/ovarian cancer predisposition (known to be associated with BRCA1 or BRCA2 genes), Lynch syndrome, and hereditary diffuse gastric cancer;
  • Inherited neurologic and muscular conditions such as Huntington’s disease, spinocerebellar ataxia, frontotemporal dementia, muscular dystrophy, and myotonic dystrophy;
  • X-linked conditions such as Fragile X syndrome, hemophilia, adrenoleukodystrophy, and Duchenne muscular dystrophy;
  • Inherited heart disease such as hypertrophic or dilated cardiomyopathy, long QT syndrome, and other arrhythmias;
  • …and hundreds of other autosomal recessive, autosomal dominant, and X-linked genetic disorders.

Some patients considering PGT have already identified the mutations in their family through DNA testing in our office or another clinic. Others know that they likely have a hereditary disease in their family but have not yet completed the genetic testing process. In the latter case, we can help facilitate the genetic testing through our office or a specialty clinic.

Read More On Single Gene PGT

CHROMOSOME REARRANGEMENTS:

These are conditions that occur in healthy people and change the structure of the usual 46 chromosomes, or packages of DNA. People who carry these chromosome changes do not experience any health effects but are at increased risk to have miscarriages or offspring with birth defects. They are often detected when a blood chromosome study is done on couple after experiencing miscarriages.

Examples include:

  • Reciprocal translocations
  • Robertsonian translocations
  • Chromosome inversions
  • Complex chromosome rearrangements

Read More On Chromosomal PGD

You can find a list of conditions for which PGT may be available here.

What factors go into a decision about PGT?

You may have already decided that PGT is right for you. Alternatively, you may be considering a variety of medical, emotional, moral, and financial factors including:

  • The chance of having a successful pregnancy or healthy child if PGT is not used;
  • Whether effective treatment is available for the condition that may be passed on;
  • Your personal likelihood of success with the IVF and PGT process
  • Whether alternatives to PGT – such as prenatal diagnosis, use of sperm/egg donors, adoption, or living childfree – are acceptable to you and your partner;
  • Your personal experience, if any, with the genetic condition

We anticipate that you may have several questions as you consider whether PGT is right for you.

Contact Oregon Reproductive Medicine for more information today.

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