Navigating triplet repeats sequencing: concepts, methodological challenges and perspective for Huntington's disease

Area of Science:

• Genetics
• Neuroscience
• Molecular Biology

Background:

• CAG triplet repeat expansions in genes like huntingtin (HTT) cause neurodegenerative disorders, including Huntington's disease (HD).
• Repeat lengths exceeding 36 CAG units trigger HD, with extreme expansions up to 800 repeats observed in affected cells.
• Single nucleotide variants within CAG repeats influence disease onset timing.

Purpose of the Study:

• To review current and evolving sequencing-based methods for characterizing triplet repeat length and sequence.
• To discuss the challenges and opportunities in analyzing triplet repeats for diagnostic and therapeutic applications.
• To use Huntington's disease as a case study for triplet repeat analysis.

Main Methods:

• Review of traditional and modern sequencing-based approaches for triplet repeat analysis.
• Discussion of target enrichment strategies, sequencing platforms, and bioinformatic pipelines.
• Exploration of experimental and computational challenges in accurate characterization.

Main Results:

• Sequencing-based methods are advancing to meet the need for precise triplet repeat profiling.
• Development of strategies for target gene enrichment and analysis is ongoing.
• Challenges remain in both experimental execution and bioinformatic analysis.

Conclusions:

• Accurate characterization of triplet repeats, particularly CAG repeats, is crucial for understanding and managing neurodegenerative diseases.
• Evolving sequencing technologies offer promising avenues for improved diagnostic and therapeutic interventions.
• Addressing experimental and bioinformatic challenges is key to realizing the full potential of triplet repeat analysis.