Please call the Department of Medical Genetics to schedule an appointment for a genetic counselling session at 514-412-4427 if not already booked.
Tay-Sachs disease (TSD)
TSD is caused by the absence of a molecule responsible for the breakdown of a specific fatty substance. As this substance is not broken down, it accumulates in the body and is toxic for the central nervous system (brain and spinal cord).
TSD is a severe condition that worsens with time. At birth, babies with TSD are normal. Symptoms appear between ages 3 to 6 months with muscle weakness. From age 6 to 12 months, as the weakness become more severe, infants start to lose motor skills such as smiling, rolling over or sitting. Infants rapidly become less responsive and develop swallowing and breathing problems. They experience gradual loss of vision leading to blindness and seizures. After 2 years of age, infants stop responding to their surroundings and they usually pass away before age 4.
There is no cure for TSD. Care is offered to improve the infants’ quality of life and includes controlling for adequate nutrition and hydration, managing infections, protecting the airways and using medication to control seizures.
Genetics
As you are both carriers of the same condition, your probabilities are 1/4 of having a child who is affected, 1/2 of having a child who is a carrier and 1/4 of having a child who is not a carrier.
Pregnancy options
Two options are 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 allows one 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.