What is the HEXA gene's role in What is the HEXa gene's role in tay-sachs?
The HEXA gene, or formally, the “hexosaminidase A (alpha polypeptide).” gene is located in the long arm of chromosome 15. It consists of the base pairs between number 72,343,437 and 72,376,179. There have been more than 120 mutations to the HEXA gene that have been attributed to the impairment of beta-hexosaminidase A production, rendering it unable to break down toxic GM2 gangliosides. When these gangliosides cannot be broken down, they destroy the neruons that surround them, resulting in the overall neurodegeneration and symptoms of the disease in the affected.
Of these 120 mutations, most result in the complete elimination of beta-hexosaminidase A activity, which results in the more common and severe form of Tay-Sachs, which manifests in infancy. Of the remaining mutations that do not completely stop the enzyme's activity comes the other, less severe form of Tay-Sachs, which does not appear until well past infancy and into adulthood.
HEXA gene. (2008, September 1). Retrieved November 28, 2015, from http://ghr.nlm.nih.gov/gene/HEXA