Asymmetric brain atrophy in Huntington's disease: A postmortem MRI study

Area of Science:

• Neuroscience
• Neuroimaging
• Genetics

Background:

• Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder.
• It results from a CAG repeat expansion in the HTT gene.
• Medium spiny neurons in the striatum are particularly vulnerable, leading to caudate and putamen atrophy.

Purpose of the Study:

• To investigate region-specific gray and white matter volume differences in Huntington's disease patients compared to controls.
• To characterize the pattern and extent of brain atrophy in symptomatic HD.

Main Methods:

• Postmortem MRI analysis of brains from 15 symptomatic Huntington's disease patients and 26 control subjects.
• Comparative assessment of regional gray and white matter volumes between the two groups.

Main Results:

• Significant gray and white matter volume reductions were observed in Huntington's disease patients.
• The largest volume decreases were noted in the caudate and putamen.
• Atrophy was predominantly left-hemisphere biased, affecting regions near the pars opercularis, precentral, supramarginal, pars orbitalis gyri, and lateral orbitofrontal cortex.

Conclusions:

• Huntington's disease is characterized by progressive, diffuse, and asymmetric gray and white matter atrophy.
• The observed hemispheric asymmetry in atrophy patterns differs from controls, though its cause remains unclear.
• This study enhances the detailed characterization of brain changes in Huntington's disease using postmortem MRI.