C9orf72-FTD/ALS pathogenesis: evidence from human neuropathological studies

Area of Science:

• Neuroscience
• Pathology
• Genetics

Background:

• C9orf72 mutations are a leading genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis (FTD/ALS).
• Model-based research on pathogenic mechanisms is advancing rapidly but yields conflicting results.
• Understanding human neuropathological findings is essential for therapeutic development.

Purpose of the Study:

• To critically review human neuropathological studies on C9orf72-FTD/ALS.
• To identify key gaps and uncertainties in current knowledge.
• To guide future research towards effective therapies.

Main Methods:

• Review of human neuropathological literature on C9orf72-FTD/ALS.
• Analysis of C9orf72-specific mechanisms (haploinsufficiency, RNA foci, dipeptide repeats).
• Examination of associated features (TDP-43 pathology, nuclear transport defects).
• Review of genetic/epigenetic factors and disease natural history.

Main Results:

• C9orf72 haploinsufficiency, repeat RNA foci, and dipeptide repeat proteins are key pathogenic mechanisms.
• TDP-43 loss-of-function, aggregation, and nuclear transport defects are prominent associated features.
• Epigenetic and genetic factors may modify disease course.

Conclusions:

• Anatomical precision in neuropathological studies is vital for correlating mechanisms with clinical and regional findings.
• Methodological advancements are needed to address knowledge gaps.
• Human neuropathological studies are critical for guiding therapeutic strategies in C9orf72-FTD/ALS.