Toppling Tay-Sachs Disease
Your nine month old daughter is always out of breath. She has trouble sitting up. Her eyes have stopped lining up and they have red spots. Your child could have Tay-Sachs disease.
Tay-Sachs disease is a genetic disorder that causes buildup of a fatty substance on tissues and nerve cells in the brain. The disease develops after the first few months of life, and relentless deterioration of mental and physical abilities occur. A child with Tay-Sachs becomes blind, deaf and unable to swallow and usually dies by age four or five.
In rare cases, adults can develop the disease. Tay-Sachs tends to be more prominent in certain ethnic groups. The incidence of the disease is particularly high among Eastern European and Ashkenazi Jews, French Canadians, Louisiana Cajuns and Irish Americans.
For people not from high-risk backgrounds, around 1 in 300 people carry the genetic change (or variant gene) for Tay-Sachs. For people of Ashkenazi Jewish descent: about 1 in 30 carry the variant gene.
Tay-Sachs is one of about 40 fatal genetic diseases of the brain, in which waste products kill cell function. It’s a degenerative neurological disorder caused by the absence of a vital enzyme known as Hex-A. Without this enzyme, brain cells become clogged and non-functioning.
According to the National Tay-Sachs and Allied Diseases Association, there are three onset levels for the disease:
· Infantile: Symptoms typically appear between the ages of 3-6 months of age.
· Juvenile: Symptoms typically appear between the ages of 2-5 years of age.
· Late onset: Symptoms typically appear in adolescence and adulthood.
The earlier in life the symptoms appear, the more quickly the disease progresses. For a person to be born of Tay-Sachs, both parents must be carriers of the recessive mutant gene. In those cases, there’s a 25 percent chance the child will be born with this disease. In advanced stages, Tay-Sachs children are unable to see, hear, eat or move. Their mentality also degenerates.
Many Tay-Sachs patients have to have feeding tubes. Anticonvulsive medication helps with seizures. Other symptoms that Tay-Sachs children will experience are low muscle tone, muscle weakness, sudden contractions of large muscles when falling asleep (myoclonic jerks), decreased eye movements and eye contact, lack of attentiveness, losing ability to do tasks they could do before (like sitting), not meeting motor milestones (like sitting up, pulling up to stand, picking objects up with all their fingers), a cherry-red spot in the eye, loss of vision, and start of seizures.
At a year and a half, your child’s head may start to grow. They may end up in a unresponsive state where there isn’t a lot of brain function going on. Age of death is usually between 2 and 4 years old. Pneumonia is often the cause of death.
Some patients experience a different form of Tay-Sachs, caused by Hex-A deficiency including juvenile Hex-A deficiency, chronic Hex-A deficiency and late onset Hex-A deficiency.
Tay-Sachs is diagnosed through a blood test where the level of Hex-A is measured in the body. In a child with classic Tay-Sachs, the protein is mostly or completely missing. Patients with other forms of the disease have reduced levels. Your doctor may perform an eye exam to see if the child has a cherry-red spot in the eye.
Genetic counseling is available for parents and relatives of Tay-Sachs children or those that suspect that they may have the condition. After a blood draw, the genetic counselor will discuss with you the different options you can take if you find out you’re a carrier.
You can undergo a prenatal diagnosis to check for Tay-Sachs in a developing fetus by checking out the chorionic villus sampling (placenta sampling) and amniocentesis (amniotic fluid sampling).
A preimplantation genetic diagnosis is another option. Specialist perform tests on your embryos before implanting them in your uterus.
The idea behind genetic counseling is give you options so you can make the appropriate choices for you and your family.
Screening for the disease in the Jewish community has significantly reduced live births of Tay-Sachs babies among Jews.
You can also discuss end of life issues with your health provider and work to make your child comfortable. But the conversation with your doctor should start when you plan to become pregnant and Tay-Sachs runs in your family so you can discuss all the options available to you.
