PGD: Preimplantation Genetic Diagnosis/Genetic Testing at IVF New Jersey

Preimplantation Genetic Diagnosis (PGD) View All Videos Preimplantation genetic diagnosis (PGD) is a type of prenatal genetic testing available at IVF New Jersey. PGD is an innovative method of screening embryos for genetic abnormalities prior to the embryo attaching to the uterus (implantation). PGD requires the use of in vitro fertilization (IVF) to obtain the embryos in the laboratory for evaluation. Achieving a pregnancy through PGD and IVF using healthy embryos can increase the chance of a successful pregnancy and decrease the risk of passing certain genetic diseases to your offspring.

PGD can be used to target specific genetic diseases when one or both parents are carriers of, or affected by, a known genetic diagnosis. Alternatively, PGD can be applied to screen embryos of genetically normal parents for genetic abnormalities that may be causing problems such as recurrent pregnancy losses or recurrent IVF failures. In some circumstances, PGD may be appropriate to select embryos for HLA-typing or for the detection of genes associated with devastating chronic diseases and some types of cancer.

Preimplantation Genetic Diagnosis (PGD) Procedure

PGD: Preimplantation Genetic Diagnosis/Genetic Testing at IVF New JerseyThe preimplantation genetic diagnosis (PGD) genetic testing procedure at IVF New Jersey begins with in vitro fertilization (IVF). The IVF procedure involves the use of hormones to stimulate the growth and recovery of multiple eggs from the ovaries in order to form several embryos for evaluation by PGD, thereby increasing the chances of finding normal or unaffected embryos for transferring back to the uterus. The evaluation of these embryos by PGD takes place in the laboratory and requires a biopsy at one of two developmental stages: cleaved embryo stage (3 days after fertilization when the embryo is composed of 6-10 cells) or blastocyst stage (>100 cells 5-6 days after fertilization). Whether the biopsy takes place at the cleaved or blastocyst stage is determined on a case-by-case basis because not every embryo is capable of reaching the blastocyst stage. Less commonly, the polar body (extra genetic material) extruded from the unfertilized egg can be biopsied to screen for maternal or egg-only chromosomal disorders. Polar body biopsies do not detect problems that occur after fertilization with the sperm.

The embryo biopsy is performed under microscopic guidance using a pipette to gently aspirate embryonic cells. An opening is made in the shell surrounding the embryo (zona pellucida) allowing access to the dividing cells inside called blastomeres. At the cleavage stage, the biopsy removes 1 or 2 of the 6-10 available blastomeres. At the blastocyst stage, the biopsied cells come from the outer layer of the embryo called trophectoderm. The goal is to obtain enough cellular material to carry on the PGD analysis without harming the embryo. Only embryos with normal biopsy results (i.e. free of the target genetic defects) are used for transfer/implantation.

The cell(s) obtained from the biopsy are immediately submitted to genetic evaluation. This can be accomplished in several ways depending on what is being studied. For example, in single gene disorders such as cystic fibrosis, PCR analysis is used to detect a specific mutation in the DNA of the embryo. If on the other hand the goal is to look for defects involving entire chromosomes FISH technology using florescent signals is employed to detect extra, missing, or abnormally structured chromosomes in the embryo. These chromosome abnormalities are referred to as “aneuploidy” (an example would be trisomy 21 or an extra chromosome 21 which causes Down’s syndrome) and “balanced translocations” which can be responsible for recurrent miscarriages. Most recently, exciting advancements have been made to develop techniques that are able to check the entire genome (all genes within the chromosomes) of the cell(s) tested and screen for both known and unknown genetic defects that may be present in the embryo. This technology is called Comparative Genomic Hybridization (CGH) and employs computer software and “DNA chips” to check for aneuploidy, translocations and single gene disorders in one single test.

Most PGD techniques mentioned above traditionally require at least 24 hours to generate results, therefore, performing the biopsy at the cleaved stage allows for the interpretation of results by the 5th day of embryo development (blastocyst stage). This is important because embryos are only able to survive up to 6 days in the laboratory otherwise they need to be frozen (cryopreserved). Therefore, the cleaved stage (day 3) biopsy technique allows for transfer of “fresh” PGD-resulted embryos. On the other hand, biopsies performed on the trophectoderm of blastocysts (day 5) may require freezing of the embryos since the turn-around time for the results may exceed the amount of the time the embryo(s) can survive in the laboratory.

Whether PGD is right for you or what type of PGD technique should be applied to any particular couple depends on what needs to be studied, the number and developmental ability of the embryos in the laboratory, and the limitations of the technique.

Diseases Detected with PGD Genetic Testing

The list of genetic defects that preimplantation genetic diagnosis (PGD) checks for is constantly growing. This genetic testing procedure can identify recessive sex-linked disorders, dominant sex-linked disorders, single gene disorders, and chromosomal aneuploides and translocations. The gender of the embryo (male or female) is usually known when PGD testing is applied, however, here at IVF NJ that information is used to select embryos only in cases of sex-linked disorders and not for family balancing purposes.

Traditionally, PGD was developed to check for genetic and chromosomal abnormalities that would always cause miscarriages, birth defects or fatal illnesses. More recently, with the completion of the human genome project, PGD can be used to screen for genes that are not a definite cause of disease at birth but may be associated with an increased risk of a chronic debilitating illness and some forms of cancer (i.e., BRCA or breast cancer gene) throughout a person’s lifetime. Genetic counseling is recommended in order to understand the risks and benefits of PGD and how screening could potentially change the risk of having affected offspring.

The list of diseases that preimplantation genetic diagnosis/genetic testing can detect at IVF New Jersey is continually evolving, and includes the following:

1. Achondroplasia

2. Adenosine deaminase deficiency

3. Alpha-1-antitrypsin deficiency

4. Alpers Syndrome

5. Alzheimer's disease (AAP gene)

6. Aneuploidies (i.e. Trisomy 21 or Down’s syndrome)

7. Beta thalasemia

8. BRCA-1 and BRCA-2 (Heriditary breast/ovarian cancer)

9. Canavan Disease

10. Congenital Adrenal Hyperplasia

11. Cystic fibrosis

12. Ehlers-Danlos Syndrome

13. Epidermolysis bullosa

14. Fanconi anemia

15. Fragile X Syndrome

16. Gaucher's disease

17. Hemophilia A and B

18. Huntington's disease

19. Marfan Syndrome

20. Muscular dystrophy (Duchenne and Becker)

21. Myotonic dystrophy

22. Neimann Pick Disease

23. Neurofibromatosis type I

24. Osteogenesis imperfecta

25. OTC deficiency

26. P53 cancers

27. Phenylketonuria

28. Polycystic Kidney Disease

29. Retinitis pigmentosa

30. Sickle cell disease

31. Spinal muscular atrophy

32. Tay Sachs disease

33. Translocations

While PGD significantly increases your chances of having normal offspring, we still recommend that patients get confirmatory genetic testing during pregnancy (CVS or amniocentesis) to ensure that their child is free of other conditions.

Family balancing through PGD and IVF

The combination of in vitro fertilization (IVF) and pre-implantation genetic diagnosis (PGD) technologies allows for the determination of the gender of the pre-embryo(s) generated by a couple seeking family balancing through assisted reproductive treatment.   The combination of IVF and PGD is the most precise way to determine if an embryo is male (XY) or female (XX) with nearly 100% accuracy (the technique carries approximately a 1% technical error rate therefore the gender of the embryo cannot be guaranteed).   Couples who already have at least one child of a particular sex and are interested in having another child of the opposite sex are welcome into our family balancing program using our highly successful IVF and PGD experience at our state-of-the-art, on site fertility center.

Fertility Preservation

Fertility Preservation techniques have been developed with the purpose of helping women, men, and children overcome the complications of infertility associated with chemotherapy and radiation therapy. IVF NJ utilizes established procedures including egg and embryo freezing, ovarian stimulation techniques, and semen freezing for cancer patients. The state of NJ has mandated coverage of fertility preservation treatments for patients who are undergoing chemotherapy or radiation for cancer.

Fertility Preservation Program

IVF NJ’s Fertility Preservation Program is intended for those women and men who are diagnosed with cancer and are concerned about preserving their future fertility. Prior to scheduling an initial appointment with IVF NJ, all patients are asked to provide medical records specific to their diagnosis and care, complete the online patient portal and other necessary forms. This allows our team to review the information prior to your visit and provide a timely treatment plan for you.

Thank you for your interest in our Fertility Preservation Program. We look forward to meeting you and helping you preserve your goal of having a family in the future.