Tay-sachs disease and sandhoff disease

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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:

Fabry disease
Gaucher disease (most common)
Krabbe disease
Metachromatic leukodystrophy
Niemann-Pick disease (types A and

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.