Cognitive phenotype and neurodegeneration associated with Tau in Huntington's disease

Area of Science:

• Neuroscience
• Neurology
• Biochemistry

Background:

• Huntington's disease (HD) exhibits significant clinical heterogeneity, particularly in cognitive decline and associated brain changes, even among individuals with similar disease burden.
• Understanding the underlying mechanisms of this heterogeneity is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate the association between Tau pathology and more severe cognitive phenotypes and brain damage in early-to-middle stage Huntington's disease.
• To explore the role of Tau biomarkers in explaining cognitive and neurodegenerative heterogeneity in HD.

Main Methods:

• A cohort of 30 early-to-middle stage HD participants underwent comprehensive neuropsychological testing.
• Structural magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) analysis were performed to quantify Tau biomarkers (tTau, pTau-231) and neurofilament light chain (NfL).
• Relationships between biomarker levels, cognitive performance, and brain integrity were analyzed.

Main Results:

• Severe cognitive deterioration in HD extends beyond executive dysfunction to posterior-cortical dependent processes.
• Higher CSF levels of tTau and pTau-231 were associated with this more severe cognitive phenotype.
• This cognitive profile correlated with pronounced posterior-cortical atrophy in brain regions implicated in Tau-related cognitive deficits.

Conclusions:

• Findings support a strong link between Tau pathology, cognitive impairment, and neurodegeneration in Huntington's disease.
• Tau pathology plays a significant role in the observed cognitive heterogeneity within HD.
• Further research into Tau's role is warranted to address HD's complex clinical variability.