About 1 in 25 Ashkenazi Jews is a carrier of Tay-Sachs disease
1 in 300
Tay-Sachs disease is a fatal AR disorder caused by a total deficiency of 'Beta - Hexosaminidase A' resulting in an accumulation of gangliosides in the brain. As gangliosides collects in the brain it kills nerve cells - which causes complications in the body, both physically and mentally. People with the disease may be identified through a simple blood test which measures 'Beta - Hexosaminidase A' activity.
aka; Autosomal recessive disorder -means two copies of an abnormal gene must be present in order for the disease to develop
Beta - Hexosaminidase A
aka; HEXA - is an enzyme that provides instructions in the brain and spinal cord that helps to break down a fatty substance called GM2 ganglioside
aka; Gangliosides GM2 (referring to Tay-Sachs) - is a group of complex lipids which are present in the grey matter of the human brain.
The gene is in approximately 1 in 300 for the rest of the population.
The symptoms include continued vision problems that result in blindness. As well as seizures, deafness, stiff muscles and paralysis. An infant’s physical, social and mental growth will stall. Adults who have a mild type of this disease may also experience symptoms, such as: speech difficulties, weakened muscles, and problems with their memory. As well as instability while walking and body tremors. Once the symptoms appear, Tay-Sachs disease will quickly advance. It most often becomes fatal when the child is four to five years of age.
Tay-Sachs disease is caused by a genetic defect on chromosome 15, HEX-A. It prevents our bodies’ ability to create a protein called 'Beta - hexosaminidase A'. It inhibits gangliosides chemicals from building up in our brain’s nerve cells. It's caused when the brain’s nerve cells are destroyed by these chemicals. Tay-Sachs is an autosomal recessive character, which means it's hereditary. It's a condition passed down to a child through defective genes in both parents. Which gives the child a 25% chance of developing Tay-Sachs disease. If only one of parent passes down the gene, the child will not be affected. However, they will be a carrier and may pass it down to their children. Most carriers are from Ashkenazi Jewish communities in Central & Eastern Europe.
People who are carriers of Tay-Sachs disease have a 50% chance of passing the active gene for the disease to their children
The risk for two carrier parents to both pass the defective gene and, therefore, have an affected child is 25% with each pregnancy
The chance for a child to receive normal genes from both parents and be genetically normal for that particular gene is 25% (The risk is the same for males and females)
It can be diagnosed when the mother is 10 to 12 weeks into her pregnancy. The test that is performed is called a chorionic villus sampling test - An amniocentesis procedure; often performed by collecting placenta cells - The cells are collected by inserting a needle into the mother’s abdomen.
Treatment for infants and children centers on easing symptoms. Those who have seizures will be prescribed anti-epileptic drugs. Physical therapy sessions help those with weakened or stiff muscles. Many children will need feeding tubes so they can get adequate nutrition.
However -Treatment can help, but this condition cannot be cured
How is Tay-Sachs Disease Treated?
All patients with Tay-Sachs disease have a cherry-red spot, easily observable by a physician using an ophthalmoscope, in the back of their eyes.