Tay-Sachs disease (patient information)
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What is Tay-Sachs disease?
Tay-Sachs disease is a rare, inherited disorder. It causes too much of a fatty substance to build up in tissues and nerve cells of the brain. This buildup destroys the nerve cells, causing mental and physical problems.
Infants with Tay-Sachs disease appear to develop normally for the first few months of life. Then, as nerve cells become distended with fatty material, mental and physical abilities deteriorate. The child becomes blind, deaf, and unable to swallow. Muscles begin to atrophy and paralysis sets in. Even with the best of care, children with Tay-Sachs disease usually die by age 4.
Tay-Sachs is most common in Eastern European Ashkenazi Jews. A blood test can determine if you carry or have the disease. There is no cure. Medicines and good nutrition can help some symptoms. Some children need feeding tubes.
What are the symptoms of Tay-Sachs disease?
The most common form of Tay-Sachs disease becomes apparent in infancy. Infants with this disorder typically appear normal until the age of 3 to 6 months, when their development slows and muscles used for movement weaken. Affected infants lose motor skills such as turning over, sitting, and crawling. They also develop an exaggerated startle reaction to loud noises. As the disease progresses, children with Tay-Sachs disease experience seizures, vision and hearing loss, intellectual disability, and paralysis. An eye abnormality called a cherry-red spot, which can be identified with an eye examination, is characteristic of this disorder. Children with this severe infantile form of Tay-Sachs disease usually live only into early childhood.
Other forms of Tay-Sachs disease are very rare. Signs and symptoms can appear in childhood, adolescence, or adulthood and are usually milder than those seen with the infantile form. Characteristic features include muscle weakness, loss of muscle coordination (ataxia) and other problems with movement, speech problems, and mental illness. These signs and symptoms vary widely among people with late-onset forms of Tay-Sachs disease.
Who is at risk for Tay-Sachs disease?
Tay-Sachs disease is an autosomal recessive condition, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Tay-Sachs disease is very rare in the general population. The genetic mutations that cause this disease are more common in people of Ashkenazi (eastern and central European) Jewish heritage than in those with other backgrounds. The mutations responsible for this disease are also more common in certain French-Canadian communities of Quebec, the Old Order Amish community in Pennsylvania, and the Cajun population of Louisiana.
How to know you have Tay-Sachs disease (Diagnosis)?
Development of improved testing methods has allowed neurologists to diagnose Tay-Sachs and other neurological diseases with greater precision. But Tay-Sachs disease is sometimes misdiagnosed at first, because clinicians are not aware that it is not exclusively a Jewish disease.
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 (the retina). This red spot is the area of the retina which is accentuated because of gangliosides in the surrounding retinal ganglion cells (which are neurons of the central nervous system). The choroidal circulation is showing through "red" in this region of the fovea where all of the retinal ganglion cells are normally pushed aside to increase visual acuity. Thus, the cherry-red spot is the only normal part of the retina seen. Microscopic analysis of neurons shows that they are distended from excess storage of gangliosides. Without molecular diagnostic methods, only the cherry red spot, characteristic of all GM2 gangliosidosis disorders, provides a definitive diagnostic sign.
Journalist Amanda Pazornik describes the experience of the Arbogast family: “Payton was a beautiful baby girl — but she would not sit up. Four months passed, and similar milestones seemed to slip away. She wouldn’t roll over. She wouldn’t play with her toys. She still wouldn’t sit up. Payton’s symptoms progressively worsened. Loud noises inexplicably startled her. An inability to coordinate muscle movement between her mouth and tongue caused her to choke on food and produce excessive saliva.” Because neither of Peyton’s parents were Jewish, Her doctors did not suspect Tay-Sachs disease until she was 10 months old, when her ophthalmologist noticed the cherry red spots in her eyes. Payton died in 2006 at the age of 3½.
When to seek urgent medical care
See your doctor immediately if your child displays any of the symptoms listed above
Treatment options
Presently there is no treatment for Tay-Sachs disease. Anticonvulsant medicine may initially control seizures. Other supportive treatment includes proper nutrition and hydration and techniques to keep the airway open. Children may eventually need a feeding tube.
Diseases with similar symptoms
Where to find medical care for yourdisease
Directions to Hospitals Treating Tay-Sachs disease
Prevention of Tay-Sachs disease
Three approaches have been used to prevent or reduce the incidence of Tay-Sachs disease in the Ashkenazi Jewish population:
- Prenatal diagnosis and selective abortion. If both parents are identified as carriers, prenatal genetic testing can determine whether the fetus has inherited a defective copy of the gene from both parents. For couples who are willing to terminate the pregnancy, this eliminates the risk of Tay-Sachs, but selective abortion raises ethical issues for many families.[1]
- Mate selection. In Orthodox Jewish circles, the organization Dor Yeshorim carries out an anonymous screening program so that couples who are likely to conceive a child with Tay-Sachs or another genetic disorder can avoid marriage.<ref># ↑ Ekstein, J and Katzenstein, H (2001). "The Dor Yeshorim story: community-based carrier screening for Tay-Sachs disease". Advances in Genetics 44: 297-310. PMID 11596991.<ref> Nomi Stone of Dartmouth College describes this approach. "Orthodox Jewish high school students are given blood tests to determine if they have the Tay-Sachs gene. Instead of receiving direct results as to their carrier status, each person is given a six-digit identification number. Couples can call a hotline, if both are carriers, they will be deemed 'incompatible.' Individuals are not told they are carriers directly to avoid any possibility of stigmatization or discrimination. If the information were released, carriers could potentially become unmarriageable within the community."<ref>↑ 21.0 21.1 Nomi Stone. Erasing Tay-Sachs Disease. Retrieved on August 16, 2006.<ref> Anonymous testing eliminates the stigma of carriership while decreasing the rate of homozygosity in this population. Stone notes that this approach, while effective within a confined population such as Hasidic or Orthodox Jews, may not be effective in the general population.<ref>↑ 21.0 21.1 Nomi Stone. Erasing Tay-Sachs Disease. Retrieved on August 16, 2006.<ref>
- Preimplantation genetic diagnosis. By retrieving the mother's eggs for in vitro fertilization and conceiving a child outside the womb, it is possible to test the embryo prior to implantation. Only healthy embryos are selected for transfer into the mother's womb. In addition to Tay-Sachs disease, PGD has been used to prevent cystic fibrosis, sickle cell anemia, Huntington disease, and other genetic disorders.<ref>↑ Marik, JJ (April 13 2005). Preimplantation Genetic Diagnosis. eMedicine.com. Retrieved on 2007-05-10.<ref> However this method is expensive. It requires invasive medical technologies, and is beyond the financial means of many couples.
What to expect (Outlook/Prognosis)
Even with the best of care, children with Tay-Sachs disease usually die by age 4, from recurring infection.
Sources
- ↑ # ↑ Stoller, David (1997). "Prenatal Genetic Screening: The Enigma of Selective Abortion". Journal of Law and Health 12. PMID 10182027.