Is PGD for Single Gene Disorders right for me?

PGD testing for Single Gene Disorders allows for couples who are carrying or affected by a genetic disorder to ensure that their child will not be affected by the genetic disease. It is important to note that PGD testing for Single Gene Disorder is only possible after one or both parents has been confirmed through genetic testing as being affected by or carrying an inherited disease. If you believe you or a family member is affected by or carrying a genetic disease and would like to complete testing, contact Viafet today to learn the most efficient method of testing based on your medical history.

If the genetic disorder in question has been previously confirmed through genetic testing, it is possible to complete PGD for Single Gene Disorder with IVF. With locations in the United Arab Emirates (Dubai and Abu Dhabi), Australia, the Kingdom of Saudi Arabia, Lebanon and more locations coming soon, Viafet's services are available to a wide network of clinicians and patients.

Genetic diseases differ in their modes of inheritance - Viafet can help you to prevent the passing on of the condition to your children regardless of inheritance mode.

Modes of Inheritance

Genetic diseases vary in the modes of inheritance. For some conditions, both parents must be carriers in order to pass the genetic disease on to their offspring. For other conditions, if one parent is carrying the genetic disease than the children are at risk of being affected by the disease.

• Autosomal Recessive Disorders: In the case of autosomal recessive conditions, two copies of the abnormal gene must be present in order for the disease or trait to develop. If both parents are non-affected carriers (heterozygous) of the condition, the chance of having a healthy non-carrier baby through natural conception is 25%, the same as the chance of having an affected (homozygous) child. There is a 50% chance of having a heterozygous unaffected child (non-affected carrier, like the parents).
• Autosomal Dominant Disorders: Autosomal dominant disorders are less common than autosomal recessive disorders. In order to inherit an autosomal dominant disorder, only one copy of the abnormal gene must be present. In cases where one of the parents is an affected carrier, through natural conception, 50% of children will be affected and the other 50% will be unaffected non-carriers.
• X-linked Disorders: X-linked disorders are always initially passed from a carrier mother (normal or mildly affected) to offspring. Male offspring (XY) who have the maternal chromosomal carrying the mutation are severely affected. Comparatively, female offspring (XX) carrying one normal X (father) and the mother's X-chromosome with mutation are much less affected. 50% of male babies will be affected and 50% of the female babies will be carriers. The daughters of men who are affected with X-linked disease are called “obligate carriers" since one of their two X chromosomes is always coming from their affected father.

How does PGD for Single Gene Disorders work?

When?

Completing genetic testing during your IVF cycle provides a wealth of information about each embryo before being transferred back to your uterus. During an IVF cycle, PGD Single Gene Disorder can be performed on day 3, 4 or 5 after Egg Retrieval by removing a single cell or cells from the developing embryo. You may simultaneously perform 24-chromosome aneuploidy screening, if requested. Results for PGD Single Gene Disorder are available 24-hours after receiving the samples. Viafet's fast reporting time allows for embryos to be transferred fresh or frozen, depending on your IVF physician's protocol.

How?

PGD Single Gene Disorder is performed by first separating genetic material from the embryonic cells and then completing the analysis based on the particular disease.

If the condition being tested for is inherited in an Autosomal Recessive pattern, a method called Sanger Sequencing is utilized. By using this approach, the change in the genetic material that causes the genetic disease in your family will be screened and will allow for your embryos to be identified as affected, carriers or chromosomally normal.

If the condition is inherited in an Autosomal Dominant or X-linked pattern, Sanger Sequencing will be utilized in addition to a second method called haplotyping. Haplotyping consists of analysing particular points around the gene where the change in genetic material which allows for a more accurate diagnosis in terms of detecting carrier embryos. Carrier embryos are affected if the condition is autosomal dominant and in the case of X-linked inheritance, the condition can be transferred from a carrier mother to her male offspring.

PGD Single Gene Disorder with HLA Matching

With today's advanced medical technologies it is now possible to cure a family member suffering from a hereditary disease curable by bone marrow or allogenic stem cell transplant. Preimplantation Genetic Diagnosis (PGD) for a Single Gene Disorder is offered to couples suffering from inherited genetic diseases. PGD can also be used to cure affected individuals if the diseases they are suffering from is curable by allogeneic hematopoietic stem cell (HSC). In order to do so, an HLA match must be identified.

HLA or Human leukocyte antigen is a part of our DNA that determines much of our immune system strength as well as plays a large role in our histocompatibility with others. In order for the body to accept and use the bone marrow or stem cells from another person it must be able to use and communicate with the donated material.

HSC transplantation represents the only curative option for severe cases of blood disorders, including beta thalassemia, sickle cell disease, Fanconi ansemia and other hemoglobinopathy disorders. The best possibilities of cure are provided by transplantation with HLA-identical sibling donors. The difficulties in finding donors makes PGD with HLA Matching during an IVF cycle a viable option for couples. Umbilical cord blood from HLA-identical siblings has been reported as an excellent source of stem cells.

During an IVF cycle, healthy embryos are identified using PGD Single Gene Disorder testing and HLA matching will be tested with the affected family member. When the mother gives birth to the child, cord blood, which contains stem cells, will be stored and may be used to treat the affected brother or sister.

Viafet's Method

Viafet has developed a PGD strategy that is optimised for HLA matching. Viafet's technique includes the analysis of a minimum of 6 polymorphic markers scattered through the HLA complex. By testing for more markers, we can reduce the occurrence of incomplete HLA-matching of the embryo and affected sibling.

Based on your medical history and the preference of you and your family members, Viafet advises you to consult with your physician in order to determine if completing PGD Single Gene Disorder testing with HLA Matching is right for you. With locations in the United Arab Emirates (Dubai and Abu Dhabi), Australia, the Kingdom of Saudi Arabia, Lebanon and more locations coming soon, Viafet's services are available to a wide network of clinicians and patients.For more information, to discuss any questions related to genetic testing, or to learn where you may complete an IVF cycle with Viafet testing, contact Viafet today.

Where can I get testing?

Talk to your IVF physician about PGD for Single Gene Disorder and if it right for you. If your physician does not yet offer Viafet testing, please suggest that they contact us - testing can get started immediately. If your physician is already offering Viafet testing, all coordination for your case will be completed between your IVF centre and Viafet's team.

With locations in the United Arab Emirates (Dubai and Abu Dhabi), Australia, the Kingdom of Saudi Arabia, Lebanon and more locations coming soon, Viafet's services are available to a wide network of clinicians and patients. If at any time during your journey you have questions or would like to speak with a Genetic Counselor, contact Viafet and we will schedule an appointment immediately.