Fertility Associates of Memphis

PREIMPLANTATION GENETIC DIAGNOSIS
Kutteh Ke Fertility Associates of Memphis, PLLC

What is PGD?
At Fertility Associates of Memphis and Memphis Fertility Lab, we perform preimplantation genetic diagnosis (PGD) of human embryos to detect abnormalities in chromosomes or hereditary conditions. The first reports of PGD used successfully in conjunction with human in vitro fertilization (IVF) appeared in the early 1990’s. Since then, hundreds of normal infants have been born through the use of advanced reproductive technology.

How is PGD performed?
PGD requires patients to undergo a cycle of in vitro fertilization (IVF) in order to have pre-embryos available for testing. Prior to transfer, the pre-embryos have one or two cells, called blastomeres, safely removed. These blastomeres are then evaluated. The results are known in one to two days. Only the normal pre-embryos are transferred to the patient’s uterus to establish a pregnancy.

What can be determined about a pre-embryo by PGD testing?
PGD can be used for determining chromosomal health (PGD-FISH) or the presence or absence of specific genes related to hereditary disease (PGD-PCR).

Chromosomal abnormalities occur when there are an incorrect number of chromosomes. Some chromosomes are more likely than others to become “unpaired,” which can lead to early embryonic demise (chromosomes 13, 16, 18, and 22) or affect term births, such as Down syndrome (trisomy 21). Numerical mistakes in the sex chromosomes can lead to Turner’s syndrome (XO), or Klinefelter’s syndrome (XXY).

Checking for normal chromosome pairing is done using a technique called fluorescent in situ hybridization (FISH). Sometimes, chromosomes can break apart and attach to other chromosomes, a condition known as translocation.

Examples of hereditary conditions caused by gene disorders are cystic fibrosis, Tay-Sachs disease, Duchenne muscular dystrophy, and sickle cell anemia, as well as X-chromosome-linked disorders. The method of analysis for gene disorders involves a technique that greatly multiplies the genetic code contained in a single blastomere, so that the specific gene or genes being looked for may be detected. This technique is called polymerase chain reaction (PCR).

Can PGD of pre-embryos improve the chance of conceiving through in vitro fertilization?
Until the development of PGD, assisted reproductive technology laboratories had to rely on the appearance of pre-embryos to decide which ones to place into the patient’s uterus to establish a pregnancy. PGD has proven that normal-appearing pre-embryos frequently have abnormal numbers of chromosomes, rendering them incompatible with the development of normal pregnancy.

For older patients and for those suffering from unexplained pregnancy loss, PGD allows embryologists to select pre-embryos balanced for the chromosomes tested. This knowledge should increase the chance of pregnancy for every pre-embryo placed in the patient’s uterus. Fewer pre-embryos will need to be replaced, which will lower the risk of multiple pregnancy.

Who can benefit from PGD?
PGD testing is recommended for couples that have a family history of inherited disease or want to prevent a sex-linked genetic disease. PGD is also available for women who have a history of unexplained miscarriage to or advanced maternal age.
Fertility Associates of Memphis is composed of fertility specialists who have completed fellowship training, specializing in infertility. We have the only board-certified reproductive endocrinologists in Memphis who offer all types of assisted reproduction. Click here for more information or to make an appointment.