Tau gene mutations and neurodegeneration

Area of Science:

• Neuroscience
• Genetics
• Pathology

Background:

• Neurofibrillary lesions of tau protein are hallmarks of Alzheimer's disease and other neurodegenerative conditions.
• The correlation between tau pathology distribution and disease symptoms is well-established.
• Genetic links between tau protein dysfunction and neurodegeneration were previously lacking.

Purpose of the Study:

• To establish a genetic link between tau protein dysfunction and neurodegeneration.
• To investigate the role of tau gene mutations in frontotemporal dementia with Parkinsonism.
• To understand how tau gene mutations lead to pathological tau accumulation.

Main Methods:

• Analysis of tau gene mutations in patients with frontotemporal dementia with Parkinsonism.
• Examination of tau protein pathology in brain cells of affected individuals.
• Investigating the impact of specific tau mutations on tau protein function and assembly.

Main Results:

• Discovery of nearly 20 mutations in the tau gene associated with frontotemporal dementia with Parkinsonism.
• All examined cases with tau mutations exhibited abundant filamentous tau pathology.
• Mutations affect tau's microtubule interaction and promote tau filament assembly.
• Intronic and some coding mutations increase exon 10 splicing, leading to four-repeat tau isoform overexpression.

Conclusions:

• Tau protein dysfunction, driven by genetic mutations, can cause neurodegeneration and dementia.
• A normal ratio of three-repeat to four-repeat tau isoforms is crucial for preventing tau pathology.
• The location of tau gene mutations influences the resulting pathological heterogeneity.