Tay-Sachs is an inherited genetic disease in which the body does not break
down fatty compounds, called gangliosides, as it should. As the gangliosides
build up in the brain, they damage the nerve cells, and then
these cells cannot function properly.
The gangliosides that build up and cause problems in Tay-Sachs disease are normally broken down by an enzyme called hex A (hexosaminidase A). There are two forms of Tay-Sachs disease, based on whether any hex A is produced or not:
In the classic or infantile form (the most
common type), the body produces no hex A. This form of the disease develops
during infancy. A baby with Tay-Sachs disease appears healthy at birth.
Symptoms usually first appear 3 to 6 months after birth, beginning with mild
motor weakness and occasional twitches of the eye (myoclonic jerks). The baby's
condition progressively gets worse with seizures, blindness, and paralysis. Death usually occurs before the child is 4 years old.
In late-onset Tay-Sachs (LOTS), the body
produces lower-than-normal amounts of hex A. This form of the disease begins
between adolescence and the mid-30s. In late-onset Tay-Sachs disease, the
symptoms such as clumsiness or mood changes may be subtle at first, later
progressing to muscle weakness and twitching, slurred speech, impaired thinking
and reasoning, and mental disorders. The life expectancy for a person with LOTS
is not known. Depending on how severe the symptoms are, the person may live as
long as someone who does not have Tay-Sachs disease.
Treatment for Tay-Sachs disease focuses on controlling symptoms and
preparing for the course of the disease. There is no cure. Additional personal
and family support measures (such as home care or respite care) may be needed
as the disease progresses.
Sarah Marshall, MD - Family Medicine & Martin J. Gabica, MD - Family Medicine & Siobhan M. Dolan, MD, MPH - Reproductive Genetics