Allison Boyd, MS, CGC

Klinefelter syndrome (KS) is a genetic condition in which a male is born with an extra X chromosome. This condition often impacts fertility (potentially in addition to other aspects of health and development), though it does not necessarily mean a person cannot have biological children. By understanding the symptoms, causes, risks, and treatments, individuals with Klinefelter syndrome can better navigate treatment options.

Turner Syndrome (TS), also known as monosomy X, is a chromosome abnormality that occurs randomly during fertilization and affects only females. It is a genetic condition that, if present in a fetus, causes significantly increased risk for miscarriage and prenatal complications such as heart defects.

After birth, individuals with Turner syndrome have an increased risk for growth issues, learning disabilities, and infertility as adults. Fortunately, with proper early intervention and counseling on reproductive options and risks, females with Turner syndrome may go on to have successful pregnancies.

Preimplantation genetic testing (PGT) is the general term for genetic testing performed on human embryos used for in vitro fertilization (IVF) and before transfer to the uterus. PGT aims to improve the chances of a successful ongoing pregnancy after embryo transfer.

While genetic testing does not impact or change the genetics of an embryo, it gives doctors and prospective parents more information and may help them select the most viable embryo(s) for transfer. It is important to understand that PGT will not improve the cumulative live birth rate of a given IVF cycle and that there are both advantages and disadvantages to PGT.

Preimplantation genetic testing (PGT) is the general term for genetic testing that is performed on embryos produced by in vitro fertilization (IVF) before the embryos are transferred to the uterus. The purpose of PGT is to improve the chances of having a successful embryo transfer. Genetic testing does not impact or change the genetics of an embryo, but it does give doctors and prospective parents more information and may help them select the most viable embryos for transfer.

There are three types of PGT: PGT for monogenic disorders (PGT-M), PGT for structural chromosomal rearrangements (PGT-SR), and PGT for aneuploidy (PGT-A). PGT-A is the most routine type performed. As such, it is an important area of education for prospective parents.

To increase the chances of a successful pregnancy, embryo grading is completed by an embryologist during an in vitro fertilization (IVF) cycle. Assessing embryos for quality at specific stages of embryo development can be a valuable tool in reproductive medicine to help the doctor decide which embryo to transfer first (when there is more than one embryo available for transfer).

Exploring epigenetics, the study of how environmental factors affect gene expression, reveals complex dynamics in the context of donor eggs used for fertility treatments. For mothers seeking a genetic connection to their donor egg–conceived child, epigenetics can provide some insight.

Epigenetic changes are reversible alterations to deoxyribonucleic acid (DNA, the genetic code) that do not alter the code itself but can influence how an embryo develops.ⁱ The dynamic interaction between inherited genetic information and environmental influences shapes the overall epigenetic profile of gametes (oocytes and sperm), the developing embryo, and fetus.ⁱⁱ Epigenetic changes are especially important during critical periods like prenatal development, where the epigenetic landscape is particularly sensitive to external cues.ⁱⁱⁱ

Chromosomes carry DNA, which forms genes that determine multiple aspects of a human’s makeup. A chromosome analysis is often performed to give a healthcare provider more insight into a range of issues, from potential genetic conditions to factors that may be causing recurrent miscarriage.

Embryonic and fetal genetic testing may be recommended for a variety of reasons. Sometimes, individuals or couples have genetic conditions that run in their families. In that case, in vitro fertilization (IVF) with preimplantation genetic testing (PGT) can help select embryos that do not carry the condition. In other cases, patients who have had multiple pregnancy losses may pursue genetic testing of an embryo to help discover a cause. Genetic testing can also give an early glimpse into the sex of the fetus as well as whether the fetus has extra/missing chromosomes that could cause conditions such as Down syndrome or Turner syndrome.