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Huntington's disease: translating a CAG repeat into a pathogenic mechanism
1Molecular Neurogenetics Unit, Massachusetts General Hospital East, Charlestown 02129, USA.
Insights
Huntington's disease (HD) involves neuronal cell death caused by an abnormal huntingtin protein. This protein arises from a gene defect, leading to an expanded CAG repeat and altered protein functions.
Area of Science:
- Neuroscience
- Genetics
- Molecular Biology
Background:
- Huntington's disease (HD) is characterized by a specific pattern of neuronal cell death.
- This neurodegeneration is linked to an abnormal huntingtin protein.
Purpose of the Study:
- To investigate the role of the expanded CAG repeat in the huntingtin gene.
- To understand how the abnormal huntingtin protein contributes to neuronal cell death in HD.
Main Methods:
- Analysis of the HD gene defect, specifically the expanded CAG repeat.
- Examination of the huntingtin protein's structure and function.
Main Results:
- The abnormal huntingtin protein, produced from the HD gene defect (expanded CAG repeat), triggers specific neuronal cell death patterns.
- The extended polyglutamine segment of the huntingtin protein may alter its inherent activity or enable new cellular pathway interactions.
Conclusions:
- The study highlights the critical role of the huntingtin protein's polyglutamine tract in HD pathogenesis.
- Understanding the normal and abnormal physiological functions of the huntingtin protein is key to developing HD therapies.
Abstract:
The specific pattern of neuronal cell death in Huntington's disease (HD) is triggered by an abnormal version of the huntingtin protein, which is produced by translation of the HD gene defect, an expanded CAG repeat in a novel 4p16.3 gene. The extended amino-terminal polyglutamine segment may act via the protein's inherent activity, increasing it or decreasing it in a graded fashion, or, alternatively, it may confer the ability to interact with a completely different set of cellular pathways, focusing attention on the HD protein's normal and abnormal physiological functions.