Polyglutamine Repeats in Neurodegenerative Diseases

Area of Science:

• Neuroscience
• Genetics
• Molecular Biology

Background:

• Age-dependent protein aggregation disorders include nine inherited neurodegenerative diseases.
• These diseases are characterized by expansions of CAG repeats encoding polyglutamine (polyQ) tracts.

Purpose of the Study:

• To review the clinical, pathological, and biological features of polyQ expansion disorders.
• To discuss insights into pathogenesis and therapeutic development from model systems and patient studies.

Main Methods:

• Review of clinical, pathological, and biological data from polyQ expansion disorder studies.
• Analysis of insights from model systems and patient research to understand pathogenesis.
• Evaluation of current therapeutic strategies and future research directions.

Main Results:

• Expanded CAG/polyQ domains are identified as the primary drivers of neurodegeneration.
• Carrier protein biology influences disease-specific manifestations.
• Neurodegeneration results from multiple downstream mechanisms, including both gain- and loss-of-function effects.

Conclusions:

• Developing effective therapies targeting single nodes is challenging due to multifactorial pathogenesis.
• Evaluating treatments for premanifest disease requires novel investigational approaches.
• Recommendations are provided for developing symptomatic, disease-modifying therapies, and biomarkers.