Emerging drivers of DNA repeat expansions.

Area of Science:

• Genetics
• Molecular Biology
• Neuroscience

Background:

• Short tandem repeat (STR) expansions are linked to hereditary repeat expansion diseases (REDs).
• REDs encompass neurodegenerative and neurodevelopmental disorders like Huntington's disease and Fragile X syndrome.
• STR expansions are also implicated in common neurodegenerative conditions such as Alzheimer's and Parkinson's disease.

Purpose of the Study:

• To review recent findings on the mechanisms driving STR instability.
• To explore the role of DNA single-strand breaks in large-scale STR expansions.
• To highlight key genetic modifiers of REDs.

Main Methods:

• Literature review of recent studies on STR instability.
• Analysis of evidence supporting DNA single-strand breaks as drivers of instability.
• Examination of the role of specific proteins in REDs pathogenesis.

Main Results:

• DNA single-strand breaks are proposed as significant drivers of large-scale STR instability.
• This instability occurs in both dividing and non-dividing cells.
• The FANCD2- and FANCI-associated nuclease 1 (FAN1) is identified as a potent genetic modifier of REDs.

Conclusions:

• DNA single-strand breaks represent a critical mechanism underlying STR instability and REDs.
• Understanding these mechanisms can inform therapeutic strategies for neurodegenerative disorders.
• Targeting key proteins like FAN1 may offer new avenues for treating repeat expansion diseases.