“Brain Atrophy Has Already Begun”: Nature Study Warns After Genetic Analysis of 1 Million People

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A large-scale genomic study found that brain atrophy begins decades before clinical symptoms appear in certain neurodegenerative diseases.

A research team led by Saha Gelfman at the Regeneron Genetics Center in the United States published the findings in the international journal Nature on the 8th. The team analyzed genomic data from more than 1 million people to identify the association between disease risk and brain atrophy.

The researchers focused on “repeat expansion disorders,” a group of neurologic diseases in which certain gene sequences are abnormally repeated, including Huntington disease and spinocerebellar ataxia. More than 70 types have been reported to date.

The analysis found that people carrying certain repeat expansion genes had reduced volumes in specific brain regions and higher levels of neurofilament light chain (NfL), a marker of neuronal damage, even before receiving a disease diagnosis.

Specifically, carriers of repeat expansions in the HTT gene associated with Huntington disease had a 22.1% reduction in putamen volume. Carriers of the CACNA1A gene associated with spinocerebellar ataxia had a 24.6% reduction in cerebellar volume.

The study is significant because it used large-scale population data to identify biological changes in disease before symptoms appear. The findings are expected to support the development of early-diagnosis biomarkers and research into treatments for repeat expansion disorders.