Pre-implantation Genetic Diagnosis (PGD)

The process of Pre-implantation Genetic Diagnosis (PGD) allows a single embryo to be screened for genetic disease prior to embryo transfer. Dr. Goldstein and the team at Fertility Specialists of Texas is able to screen embryos for numerous reasons including inheritable disease, genetic defects and even gender.

Preconception Genetic Counseling

Screening Embryos For:
Chromosome Number (i.e., Down’s Syndrome)
Single Gene Mutations (i.e., Cystic Fibrosis)
Inheritable Cancers
Gender For Family Balancing

Examples of specific genetic diseases PGD has been utilized to prevent

Achondroplasia
Adenosine deaminase deficiency
Alpha-1-antitrypsin deficiency
Alzheimer's disease (AAP gene)
Beta thalasemia
Cystic fibrosis
Epidermolysis bullosa
Fanconi anemia
Gaucher's disease
Hemophilia A and B
Huntington's disease
Muscular dystrophy (Duchenne and Becker)
Myotonic dystrophy
Neurofibromatosis type I
OTC deficiency
P53 cancers
Phenylketonuria
Retinitis pigmentosa
Sickle cell disease
Spinal muscular atrophy
Tay Sachs disease
Any genetically abnormal embryos (i.e. Trisomy 21, 13.)

We utilize the services of specialized laboratories to do the specific analysis for depending on the specific indication for doing the PGD study. We are able to offer PDG for any genetic disorder for which the sequence DNA information is known therefore, the list is increasing as new genes are identified. Below are four reference laboratories that have experience with PGD.

Gene Security Network
2686 Middlefield Road Suite C
Redwood City, CA 94063
Tel 650-249-9090
www.genesecurity.net

Reproductive Genetics Institute
2825 North Halsted
Chicago, Illinois 60657
Tel 773-472-4900
www.reproductivegenetics.com

Reprogenetics
Tel (973) 436-5012
www.reprogenetics.com

Genesis Genetics Institute, LLC
5555 Conner Avenue, Suite 1100
Detroit, MI 48213
Tel/fax 313-544-4006
www.genesisgenetics.org

What is the Process of PGD?

Trying to build a family when you carry a genetically transmittable disease or condition can be terrifying. Fertility Specialists of Texas and Dr. Jerald Goldstein are extensive experience in the use of preimplanation genetic diagnosis, a technology that is available to significantly reduce the chances of giving birth to a child who as a specific genetic condition. By reducing the possibility that your child may inherit a specific genetic disease, we believe you will have less fear and anxiety that may accompany pregnancy. Preimplantation genetic diagnosis offered at Fertility Specialists of Texas offers couples the opportunity to conceive and have children without further worry

What is the process of doing an embryo biopsy?

When an embryo reaches the third day of development, it has approximately eight ccells. Each of these cells is called a "blastomere" and can be removed from the embryo. This process can be done using a special lazer that allows the embryologist to carefully remove this one cell or two cells without damaging the remaining cells. These cells then undergo genetic analysis to determine if they carry a specific disease mutation.

What is the role of chromosomes in reproduction and fertility?

Chromosomes are thread-like structures found in all human cells except red blood cells. Chromosomes contain genes that are made of DNA. In each of our cells we expect to find a total of 46 chromosomes or 23 pairs. We receive 23 chromosomes from each parent. The first 22 pairs are the same for men and women. The 23 rd pair, either X or Y chromosome determines our sex.

What is the difference between a gene and a chromosome?

Genes are segments of DNA that determine specific traits, such as eye or hair color. Chromosomes have many genes which are tightly coilded strands of deoxyribonucleic acid ( DNA). A gene mutation is an alteration in your DNA. It can be inherited or acquired during your lifetime, as cells age or are exposed to certain chemicals. Some changes in your genes result in genetic disorders

Chromosome abnormalities include aneuploidy which means that the chromosomes number is either two many or few. Structural abnormalities include translocations, inversions and deletions of certain chromosomes. Both kinds of chromosomal abnormalites can be present in the egg or sperm and the most common abnormality is aneuploidy.

How does PGD allow the identification of chromosomal abnormalities?

Following your egg retrieval, the embryos can be tested prior to being replaced into the uterus. Using a technique called Comparative Genomic Hybridization (CGH) we can test for aneuloidy of all 22 chromosomes including the sex chromosomes. The use of Flouresent In Situ Hybridization (FISH) is another technique that may be used that allows the analysis of chromosomal abnormalities. The image below shows a normal FISH analysis. The second image shows three blue chromosomes corresponding to three number 21 chromosomes.

PGD allows us to separate the chromosomally normal embryos from chromosomally abnormal embryos so that only normal embryos are transferred into the uterus.This technology is useful in couples where there is a known translocation present.

Normal Chromosomes as demonstrated by FISH

The image above shows a "dot" for each chromosome identified. Normally, we have two pairs of each chromosome except for sex chromosomes which are either two X chromosomes or an X and a Y chromosome

Trisomy 21 as demonstrated by FISH

The image above show three blue spots corresponding to three chromosomes. This identifies an embryo that is trisomy 21

Does your center have experience with Day Five embryo biopsy ?.

Our embryologist at Fertility Specialists of Texas has received specialized training in doing embryo biopsy's on day five. Because CGH typically takes more than 5 days to get a result, the embryos are usually frozen and transferred at a later time.

This new technique in preimplantation genetic screening (PGS) offers a complete genetic analysis of multiple cells on five-day-old embryos, replacing inspection of the genetic material in one cell from an embryo on the third day after IVF egg retrieval. The biopsy itself involves taking cells from the Trophectoderm of the embryo as noted below.

The embryo transfer is therefore performed after the results of the biopsy have been obtained. Patients will undergo the normal IVF process so the cell biopsy can be performed. After the embryos have been frozen and the results are reviewed, the patient can then undergo a frozen embryo transfer. It is very important that a program have an excellent rate of freezing and thawing embryos or the process of cryopreservation may damage normal embryos and reduce the chance of implantation or pregnancy.