The GM2 gangliosidoses
A ganglioside is a special type of lipid or fat that is especially found in brain cells. The brain needs gangliosides to function.
The GM2 gangliosidoses are a group of lysosomal storage disorders caused by changes known as mutations, in at least one of three genes: HEXA, HEXB, and GM2A.
All of the GM2 gangliosidoses are rare diseases. As they are similar, you may also hear the term ‘GM2 condition’ used when referring to either Tay-Sachs or Sandhoff disease.
In someone without Tay-Sachs or Sandhoff diseases, the three genes – HEXA, HEXB, and GM2A – contribute to the production of the enzyme beta-hexosaminidase A.. The enzyme beta-hexosaminidase A speeds up (catalyses) the normal breakdown (catabolism) of the GM2 gangliosides.
In someone with one of these diseases, the mutations in the genes result in not enough of the enzyme beta-hexosaminidase A being produced. This leads to a build-up of the GM2 gangliosides inside cells of the brain and spinal cord, causing the clinical symptoms of the disease and resulting in cell dysfunction and death.