Tay-Sachs disease (patient information)

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 * Assistant Editor(s)-in-Chief: Meagan E. Doherty

Overview
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.

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.

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

 * Sandhoff disease

Where to find medical care for yourdisease
Directions to Hospitals Treating Tay-Sachs disease

Prevention of Tay-Sachs disease

 * Mate selection
 * 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.
 * Prenatal diagnosis and selective abortion.

What to expect (Outlook/Prognosis)
Even with the best of care, children with Tay-Sachs disease usually die by age 4, from recurring infection.