Details of testing and possible results

What are the steps that you need to follow in order to find out if you are a carrier?

Step One: Go through this program, which you are already doing.

Step Two: At the end of the program, print the appropriate documents, including an instruction form and the appropriate requisition form, allowing you to have a blood draw to be tested.

Step Three: Go to the Test Centre of the McGill University Health Centre Glen site for your blood draw. The sample consists of 1 or 2 tubes of blood.

Step Four: Wait while the test is performed. This step usually takes 2 months, unless you or your partner is pregnant, in which case, it generally takes approximately 4 weeks.

Step Five: Receive a phone call from a genetic counsellor and find out if you are a carrier of one of the 3 Jewish genetic disorders, then receive a copy of your results by regular mail or e-mail. If you haven’t received a call from us within 3 months of your blood draw, or 5 weeks if you or your partner is pregnant, please contact the Department of Medical Genetics at 514-412-4427, or directly contact the genetic counsellor who initially contacted you.

What does the test consist of?

The genetic test is done from a blood sample and looks at specific mutations in the genes causing Tay-Sachs disease, Canavan disease and familial dysautonomia. Those mutations, or genetic changes, are the ones most commonly found in individuals affected with these conditions in the AJ community.

What are the possible results for me?

A negative result for a condition would mean that you are likely not a carrier of the condition. If your test result is negative, there remains a very small chance that you are a carrier as the test does not test for all the mutations.

A positive result for a condition would mean that you are a carrier of the condition. If your partner is of AJ ancestry, s/he is eligible to take the screening test and find out if s/he is a carrier.

What are the possible results for my partner and me?

If both you and your partner have a negative result for the same condition, your chance of having a child with this genetic condition would be very low. Thus, no further testing would be needed.

If one of you had a positive result and the other had a negative result for the same condition, your chance of having a child with this genetic condition would be low. Further genetic testing may be considered.

If both you and your partner had a positive result for the same condition, your probabilities would be 1 in 4 of having a child who is affected, 1 in 2 of having a child who is a carrier and 1 in 4 of having a child who is not a carrier. If this situation occurs, meeting with a genetic counsellor to discuss your pregnancy options would be recommended.

Are there prenatal testing options available if my partner and I are carriers of the same condition?              

Two options would be available to test your pregnancy. One is performed in the first trimester of pregnancy and the other is performed from the second trimester. Both procedures allow one to know whether the baby is affected by the condition, but both are associated with an increased risk of pregnancy loss (miscarriage).

Another option would allow you to know if the baby will be affected with the condition before getting pregnant. The procedure is done with the help of assisted reproductive technologies. Eggs and sperm are collected and fertilized in the laboratory. After fertilization, embryos are tested for the specific condition and only unaffected embryos are implanted in the mother’s womb. 

Choosing a diagnostic procedure as a pregnancy option is a couple`s personal choice. Other non-diagnostic options are also available including 1) choosing not to test the pregnancy; 2) using an egg and/or a sperm donor, who is someone who is not a carrier of the condition; or 3) adopting a child.