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Tay-Sachs Disease and Sandhoff Disease

By

Matt Demczko

, MD, Sidney Kimmel Medical College of Thomas Jefferson University

Last full review/revision Apr 2020| Content last modified Apr 2020
Click here for the Professional Version

Tay-Sachs disease and Sandhoff disease are types of lysosomal storage disorder called sphingolipidoses and are caused by a buildup of gangliosides in the tissues in the brain. These diseases result in early death. Hereditary diseases occur when parents pass the defective genes that cause these diseases on to their children.

  • Tay-Sachs disease and Sandhoff disease occur when the body lacks enzymes needed to break down gangliosides.

  • Symptoms include intellectual disability and blindness.

  • The diagnosis may be made by prenatal screening tests.

  • These diseases cause premature death.

  • These diseases cannot be treated or cured.

There are different types of inherited disorders. In Tay-Sachs disease and Sandhoff disease, both parents of the affected child carry a copy of the abnormal gene. Because usually two copies of the abnormal gene are necessary for the disorder to occur, usually neither parent has the disorder. (See also Overview of Hereditary Metabolic Disorders.)

Sphingolipidoses occur when people do not have the enzymes needed to break down (metabolize) sphingolipids, which are compounds that protect the cell surface and serve certain functions in the cells. There are many other types of sphingolipidoses:

In Tay-Sachs disease and Sandhoff disease, gangliosides, which are products of fat metabolism, accumulate in brain tissue. Gangliosides build up in affected children because the enzyme needed to break down gangliosides, called hexosaminidase A, is not working correctly.

Tay-Sachs disease

This disease is most common among families of Eastern European (Ashkenazi) Jewish origin.

Children with this disease start missing developmental milestones after 6 months of age and become progressively intellectually disabled, meaning that intellectual disability gets worse throughout the life of the child, and appear to have floppy muscle tone. Muscle tightness and stiffness develop, followed by paralysis, dementia, and blindness. These children usually die by age 5.

Before conception, parents can find out whether they are carriers of the gene that causes the disease. Carriers are people who have an abnormal gene for a disorder but who do not have symptoms or visible evidence of the disorder. People who carry the gene should receive genetic counseling because there is a risk they will pass the disorder on to their children. The disease develops when both parents are carriers.

During pregnancy, Tay-Sachs disease can be identified in the fetus by the prenatal screening tests chorionic villus sampling or amniocentesis.

After birth, blood tests can be done to determine levels of the missing enzyme hexosaminidase A or to analyze the DNA.

The disease cannot be treated or cured.

Sandhoff disease

This disease is very similar to Tay-Sachs disease. However, unlike Tay-Sachs disease, Sandhoff disease is not associated with any specific ethnicities.

Beginning at 6 months of age, children become progressively intellectually disabled and blindness develops. Sounds may seem abnormally loud (a condition called hyperacusis). Children also have an enlarged liver and bone problems.

Diagnosis of Sandhoff disease is the same as for Tay-Sachs disease.

The disease cannot be treated or cured.

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