Genetic conditions more common in the Ashkenazi Jewish (AJ) community

What are the conditions that occur more frequently in the AJ population and for which the MUHC offers testing?

Centers around the world offer testing for different numbers of Jewish genetic disorders. Following the joint recommendations of the Canadian College of Medical Geneticists (CCMG) and the Society of Obstetricians and Gynaecologists of Canada (SOGC), we offer screening for Tay-Sachs disease, Canavan disease and familial dysautonomia.

Tay-Sachs Disease (TSD)

TSD is caused by the accumulation of a substance in the body that is toxic for the brain and spinal cord. The brain and spinal cord are responsible for awareness, movements, vision, hearing, and speech. TSD is a severe condition that worsens with time. Symptoms appear between ages 3 to 6 months and the majority of children die before age 4. There is no cure for TSD and care is offered to improve the infants’ quality of life.

[collapsed title="Read more"]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. [/collapse]

Canavan Disease (CD)

CD is also caused by the accumulation of a substance in the body that is toxic for the brain and spinal cord. The brain and spinal cord are responsible for awareness, movements, vision, hearing, and speech. CD is a severe condition that worsens with time. Symptoms appear between ages 3 to 5 months and life expectancy ranges from childhood to teenage years. There is no cure for CD and care is offered to improve the children’s quality of life.

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CD is caused by the absence of a molecule responsible for the breakdown of a specific 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). This causes changes in the texture of the brain matter.

CD is a severe condition that worsens with time. At birth, babies with CD are normal. Symptoms vary and appear between ages 3 to 5 months with muscle weakness and when, due to a bigger than average head size, head control is problematic. As the weakness becomes more severe and muscles become stiffer, infants fail to achieve new motor and language skills such as rolling, sitting, standing, walking or talking. Infants learn to interact socially as they can laugh, smile and reach for objects. As children age, they develop sleeping difficulties as well as swallowing problems and seizures. They often experience gradual loss of vision and hearing leading to blindness and deafness. Some children die in childhood whereas others live into their teens. 

There is no cure for CD. Care is offered to improve the children’s quality of life and includes controlling for adequate nutrition and hydration, managing infections, protecting the airways and using medication to control seizures. Physical therapy and special education programs can help with muscle weakness.

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Familial Dysautonomia (FD)

FD is caused by the absence of a molecule responsible for the development and maintenance of specific nerves. Children will have sensation problems as well as difficulties with the muscles in the body that we can’t control, leading to problems with their heartbeat, respiration rate, digestion, urination, etc. FD is present from birth and half of individuals will reach age 30. There is no cure for FD and care is offered to improve the individuals’ quality of life.

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FD is caused by the absence of a molecule responsible for the development and maintenance of specific nerves. It affects the sensory system and the involuntary nervous system, which regulates the muscles in the body that we can’t control including the heartbeat, respiration rate, digestion, urination, etc.

FD is present from birth. Infants can have muscle weakness and most have developmental delays. Possible symptoms are bowel problems, vomiting, frequent pneumonia, abnormal blood pressure or heartbeat as well as insensitivity to pain and temperature. Some individuals will have crises that cause vomiting, unstable blood pressure, excessive sweating and swallowing difficulties. As individuals age, their leg muscles become stiffer and they can develop balance problems. Life expectancy is reduced and half of individuals will reach age 30.

There is no cure for FD. Care is offered to improve the individuals’ quality of life and includes controlling for adequate nutrition and hydration, managing infections, monitoring heartbeat and being followed in physiotherapy.

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