Polymorphic CGG repeats in gene regulation and disease

Area of Science:

• Genomics
• Molecular Biology
• Epigenetics

Background:

• Polymorphic CGG repeats are DNA elements found at many human genome locations.
• Initially viewed as disease-causing, they are now known to regulate gene transcription, chromatin, and RNA.
• Expanded CGG repeats are linked to neurodevelopmental and neurodegenerative disorders.

Purpose of the Study:

• To review the dual roles of CGG repeats in gene regulation and disease.
• To summarize current understanding of CGG repeat expansion mechanisms in disorders.
• To highlight emerging non-neurological phenotypes associated with CGG repeats.

Main Methods:

• Review of current scientific literature.
• Analysis of recent advances in long-read sequencing technologies.
• Integration of findings on CGG repeat polymorphisms, methylation, and structural patterns.

Main Results:

• CGG repeats act as dynamic modulators of gene expression, chromatin state, and RNA metabolism.
• Expanded CGG repeats can cause disease via transcriptional silencing, RNA toxicity, and repeat-associated non-AUG (RAN) translation.
• Long-read sequencing has identified novel CGG repeat expansion loci and complex patterns linked to human disorders.

Conclusions:

• CGG repeats are crucial for gene regulation, genome stability, and disease susceptibility.
• Understanding CGG repeat expansions provides insights into both neurological and non-neurological conditions like cardiomyopathy.
• Further research into CGG repeat mechanisms can reveal convergent and distinct pathogenic pathways across disorders.