The HEXA gene provides the instructions for creating the alpha subunit of the enzyme beta-hexosaminidase A. This enzyme plays a crucial role in breaking down gangliosides, a type of lipid found in the brain and other tissues. The HEXA gene is located on chromosome 15. Mutations in the HEXA gene can lead to Tay-Sachs disease, a severe neurological disorder.
HEXA Gene: A Deeper Look
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Function: The HEXA gene encodes a protein that's a subunit of beta-hexosaminidase A, a lysosomal enzyme. This enzyme is vital for the breakdown of specific lipids (gangliosides) within cells. The alpha subunit produced by HEXA combines with a beta subunit (encoded by the HEXB gene) to form the active enzyme.
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Location: The HEXA gene is situated on chromosome 15q23. It spans approximately 40 kb and comprises 14 exons.
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Clinical Significance: The most significant implication of HEXA is its role in Tay-Sachs disease. Mutations within the HEXA gene result in a deficiency or absence of functional beta-hexosaminidase A. This deficiency leads to the accumulation of gangliosides, causing progressive neurological damage characteristic of Tay-Sachs disease.
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Protein Product: The HEXA gene's protein product is the alpha subunit of beta-hexosaminidase A. This subunit, along with the beta subunit from the HEXB gene, forms the complete, functional enzyme. The alpha and beta subunits share approximately 60% amino acid sequence identity.
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Related Genes: The HEXB gene encodes the beta subunit that partners with the alpha subunit from HEXA to create the fully functioning beta-hexosaminidase A enzyme.
HEXA Gene: Key Takeaways
- The HEXA gene directs the synthesis of the alpha subunit of beta-hexosaminidase A.
- Beta-hexosaminidase A is essential for breaking down gangliosides.
- HEXA gene mutations cause Tay-Sachs disease.
- The HEXA gene is located on chromosome 15.
