Prevent the transmision of single gene diseases in a family and achieve a healthy pregnancy
1. Introduction. What is it?
Preimplantation genetic diagnosis (PGD) for single gene disorders is a powerful genetic test that may be performed during IVF treatment to screen embryos that are at risk to develop a serious genetic disease. PGD is performed on a small embryo biopsy and identifies which embryos are not at increased risk of developing the disease. The goal of PGD testing is to help couples build a healthy family. PGD is done before the pregnancy is established and helps avoid difficult decisions and situations.
Common examples of conditions caused by mutations in single genes (monogenic diseases) include beta thalassaemia, sickle cell anaemia, duchenne muscular dystrophy, spinal muscular atrophy (SMA), cystic fibrosis, and Fragile X disease. During the IVF process, PGD can be used to screen embryos for these conditions. Embryos that are not at increased risk for developing the single gene disorder are identified and preferentially transferred for the pregnancy. The goal of PGD testing is to help couples build healthy families.
To perform PGD testing, a pre PGD work-up is required. A unique probe is customized for each couple and used to perform PGD testing on embryos. To build the probe, blood samples from the couple and often from other family members are required. Igenomix’ team is made up of the world’s finest experts in the PGD field who are able to design probes for even the most rare and complicated mutations. Our pre-PGD workup is the first in the country to offer such services.
Igenomix uses state of the art technology for PGD. Whenever possible, Igenomix uses a multiple detection approach to ensure the most highly reliable results. Using direct detection, PCR is used to detect the specific disease causing mutation. Linkage analysis uses PCR to detect informative STR markers that are linked to the disease-causing gene. Our multiple detection strategy minimizes the chances of no results or misdiagnosis due to allele drop out (ADO). With our technology, our PGD testing is 98-99% accurate.
2. Who should use PGD testing?
Fertile couples who have a known history of a genetic condition in their families can consider PGD testing. Couples who are already undergoing IVF therapy for infertility can consider additional pre-conception screening to identify conditions for which their offspring might be at increase risk of developing. PGD testing could then be considered for any condition for which the couple’s offspring are at risk. Our goal is to prevent transmission of monogenic diseases that cause seriously illnesses to future generations.
At Igenomix, we can perform PGD for virtually any single gene disorder. Below is a list of diseases commonly tested for at Igenomix.
Panel of Frequent Monogenic Diseases**
- Autosomal Dominant Polycystic Kidney Disease
- Autosomal Recessive Polycystic Kidney Disease
- Becker muscular dystrophy
- Beta thalassaemia
- Congenital adrenal hyperplasia (gene CYP21A2)
- Cystic fibrosis
- Charcot-Marie-Tooth type 1A
- Duchenne muscular dystrophy
- Familial amyloid polyneuropathy
- Fragile X syndrome
- Hemophilia A (F8)
- Hemophilia B (F9)
- Huntington’s disease
- Multiple endocrine neoplasia, type 2A
- Myotonic dystrophy (Steinert)
- RhD incompatibility
- Sickle cell anaemia
- Spinal muscular atrophy
- X-linked adrenoleukodystrophy
3. What are the advantages of PGD testing with Igenomix?
- Identify embryos affected with a genetic disease prior to implantation
- Unique probe custom designed for every couple
- Shortest turnaround time for pre PGD work-up in the country:
- 2 weeks for common diseases/mutations
- 8 weeks for rare diseases/mutations
- We offer complete PGD counseling at a minimal cost
- World’s finest experts in the PGD field who are able to design probes for even the most rare and complicated mutations
- Senior team who analyze results for every embryo
- Onsite training of embryologists available
- Guaranteed outstanding customer service
1. To perform PGD for a single gene disorder, is it required to have identified the mutation causing the disease?
In most cases, documentation of the mutation responsible for the disorder is necessary. In some cases, a clinical report with a clear family history can be sufficient.
2. Should PGS for aneuploidy screening be performed in conjunction with PGD testing?
Aneuploidy is a numerical chromosome abnormality. Igenomix recommends that PGS for aneuploidy screening be performed on conjunction with PGD testing. Both tests can be done on the same embryo biopsy, and so there is no additional risk to the embryo to do PGS testing. PGS for aneuploidy screens for abnormalities in chromosome numbers that could cause miscarriage or could result in the birth of a baby with birth defects and mental retardation. Down syndrome is an example of a genetic disease that is caused by a numeric chromosome abnormality. The risk of having embryos with aneuploidy increases with maternal age. The goal of PGS testing is to identify embryos that are the most likely to develop to term and to be born healthy.
3. After the probe has been developed, how soon must IVF be completed?
After the probe has been developed, the IVF cycle and testing of embryos can be completed at the convenience of the patient and the clinic. The probe can be kept long term. Patients needing to delay IVF for longer than 6 months after the probe has been developed should make special arrangements with Igenomix.
4. If PGD testing has been done for a previous cycle, is there still a set-up time required for another PGD cycle?
No, there is no pre PGD work-up time necessary for subsequent PGD cycles. This is because the same probe that was made for the couple can be used again for any future testing. If a probe has been made for previous PGD testing with Igenomix, we can proceed directly with embryos testing for future PGD cycles.