GM2 gangliosidoses - Tay-Sachs and Sandhoff disease

The GM2 gangliosidoses are a group of related genetic disorders that result from a deficiency of the enzyme beta-hexosaminidase. This enzyme catalyzes the biodegradation of fatty acid derivatives known as gangliosides. The diseases are better known by their individual names. Tay–Sachs and Sandhoff disease are rare and between two and six children a year are born with the diseases in the UK. However, 1 in 300 people are carriers of the genes which cause either Tay-Sachs or Sandhoff disease. Unfortunately there is no cure or treatment currently available for Tay-Sachs and Sandhoff. The research team investigating the diseases are very close to finding an effective treatment and this gives some hope to families.


Tay-Sachs is a genetic disorder caused by a defect in the HEXA gene which produces the beta-hexosaminidase A enzyme. The enzyme is important as it breaks down harmful waste products in the brain and without it these build up and cause extensive damage to the brain’s nerve cells. Physically, an individual diagnosed with Tay-Sachs will suffer a relentless deterioration of mental and physical abilities.


Infantile Tay-Sachs and Sandhoff are the earliest presenting forms of the diseases in children and usually results in death by the age of 5.


Juvenile Tay-Sachs and Sandhoff is a very rare form of the diseases in children and is the result of a lack or severely reduced level of enzyme activity.


Late Onset Tay-Sachs and Sandhoff, also known as Adult Onset, is a very rare form which usually occurs in individuals in their 20s and early 30s.


Sandhoff disease is very similar to Tay-Sachs but the defected gene, called HEXB, does not allow the production of two enzymes (beta-hexosaminidase A and beta-hexosaminidase B). The disease also results in premature death in a sufferer and the signs and symptoms are the same as in Tay-Sachs.