Woodside_park Synagogue

Tay Sachs

by Dr Phil Koch, Consultant Pathologist

Tay Sachs Disease is fatal. There is currently no cure or treatment and children born with it will have a life expectancy of around three years.

Tay Sachs Disease is a recessive, inherited, infantile disease that results from a deficiency of a particular enzyme due to a defective gene. In short, if both parents coincidentally have a mutant gene there is a great possibility they will transmit the disease to their baby.

The disease is particularly prevalent in the Jewish population and, in particular, those of Ashkenazi origin. It is estimated that 1 in 20 of the Jewish community is a carrier of the Tay Sachs gene. Therefore, the Jewish population falls into a high-risk group. In the non-Jewish community the carrier concentration is about 1 in 250.

The disease has been called the "Hidden Killer" because there are many people who are totally unaware that they are carriers. You cannot be sure that just because you do not know of any Tay Sachs disease in your family that you are not a carrier of the disease.

A carrier is a perfectly healthy person and does not suffer from any symptoms of the disease and can carry on a normal healthy life.

A single carrier cannot cause the disease. If a carrier partners a non-carrier, then their children will not have the disease but there will be a 50% chance that they too will be carriers. However, if a carrier partners another carrier the risks change dramatically. There will be a 25% chance that their children will be free from the disease, a 50% chance that they will be carriers and a 25% chance that they will inherit the fatal Tay Sachs disease.

So how does one know whether or not they are a carrier? Well there is a simple blood test that will determine this. A small quantity of blood is taken from the arm and sent to a laboratory for evaluation. The results are sent to you and kept strictly confidential and not disclosed to any other person.

It is advisable to have this test performed before contemplating marriage. If two carriers do marry they must be aware of the potential risks. If they conceive a child it is possible to have the foetus tested at 10 weeks by a procedure known as CVS (chorionic villus sampling) or at 16 weeks by another procedure called amniocentesis. If the foetus is found to be positive then the couple might consider a termination, aware that subsequent pregnancies have a 75% chance of producing a healthy foetus. The advice of the Chief Rabbi is that couples who find themselves in this situation should speak to their rabbi as soon as possible.

However, in the event of a Tay Sachs child being born the parents must be aware that there is no cure. The only treatment is supportive.

Superficially, up to six months, the child appears fairly normal albeit quiet, apathetic and listless with difficulty in feeding. However, as time goes on characteristic symptoms develop.

  • A cherry-red spot appears on the retina
  • The inability to sit up
  • Listlessness or lack of awareness
  • The inability to hold up the head
  • Abnormal limb movement
  • Exaggerated response to sound - the so-called STARTLED EFFECT
  • Spasticity

The disease progressively destroys the brain and central nervous system. Blindness and deafness usually occur between the 12th and 18th month and, by two years of age, the child cannot feed and must be fed through a tube. The average duration of the disease is 24- 36 months. Death usually results from pneumonia following an intercurrent infection.

The nursing care required, especially during the later stages of the disease, is extremely demanding even for trained nurses and may prove too much for some parents to cope with.

In 1959 my wife and I had our first child. He was a healthy boy with no abnormalities. In 1961 our second child was born, a girl, also "apparently" healthy at birth. However, as time went on it became apparent that she was not healthy and began to exhibit the characteristics already outlined. She was diagnosed as having TSD. We were devastated. There was so little known then that we had no facility for counselling or help. With no past history in the family, the issue came as a massive shock. Obviously we were both carriers but had been totally unaware. There was no means available then for testing for carrier presence.

Our daughter died in 1963. Now knowing that we were both carriers and that the statistical odds were 75% in favour of having a healthy child (albeit it perhaps a carrier) we risked having another child. But the odds worked against us and in 1964 we had another TS child who died in 1966. Again at that time there was no diagnostic procedure available to check for carrier status or to check the foetus for TSD. So the whole agonising procedure was repeated. Even with our prior knowledge and self-counselling, the anguish and trauma were still there - to leave a deep psychological effect on my wife and son.

Today, however, I am pleased to say the situation is different. Devastated by my own experience, as a pathologist I decided to attempt to devise a test. By 1969 I had managed to formulate a very accurate and fairly simple diagnostic test requiring no more than a few millilitres of blood being taken. For the first time screening for TSD had become possible. By CVS or amniocentesis we could even identify it in the foetal stage at 10-16 weeks of pregnancy. These same procedures are still in use.

Since the disease is genetic, it is passed from parent to child. It follows, therefore, that if both parents have been tested and found to be non-carriers, then their children will also be non-carriers and need not ever be tested.

It should be noted that even if one partner is a non-carrier the other partner should always be tested in order to determine, whether or not, any offspring might be carriers.

If one parent is a carrier then there is a possibility that their children may be carriers too, therefore the children should be tested.

My advice is to get tested since AWARENESS is the key factor in combating this disease. To be AWARE is a policy for safety, to be UNAWARE is a policy for disaster.

If you wish to be screened and/or if you require counselling contact Jess Clare on 020 8904 2925.