#14 Tay-Sachs Disease

What are the symptoms of TSD?

- Development slows down and muscles used for movement weaken - Infants lose motor skills such as turning over, sitting, and crawling. - Infants develop an exaggerated startle reaction to loud noises. - As the disease progresses, children experience seizures, vision and hearing loss, intellectual disability, and paralysis. - Eye abnormality called a cherry-red spot - Children usually live only into early childhood.

How can we diagnose TSD?

- Diagnosis is through a simple blood test, which is analyzed by enzyme assay or DNA studies. - Prenatal diagnosis can also be performed via CVS or amniocentesis testing - Eye examination for the cherry-red spot in the retina of the eye

What does mutations in the HEXA gene result in?

Mutations in the HEXA gene disrupt the activity of beta-hexosaminidase A, which prevents the enzyme from breaking down GM2 ganglioside. As a result, this substance accumulates to toxic levels, particularly in neurons in the brain and spinal cord. Progressive damage caused by the buildup of GM2 ganglioside leads to the destruction of these neurons.

What genes are affected by TSD?

TSD affects the HEXA gene. This gene provides instructions for making part of an enzyme called beta-hexosaminidase A, which plays a critical role in the brain and spinal cord. This enzyme is located in lysosomes. Within lysosomes, beta-hexosaminidase A helps break down a fatty substance called GM2 ganglioside.

What is Tay-Sachs Disease?

Tay-Sachs disease is a rare inherited disorder that progressively destroys nerve cells (neurons) in the brain and spinal cord.