Ancient viruses in human DNA linked to psychiatric disorders.

Scientists from King’s College London have discovered that ancient viruses embedded in human DNA, known as Human Endogenous Retroviruses (HERVs), may contribute to psychiatric disorders such as depression, schizophrenia, and bipolar disorder. This finding challenges the previous belief that these ‘fossil viruses’ were merely ‘junk DNA’ with no function, opening potential new avenues for treatment.

Key Findings:

  1. HERVs and Psychiatric Disorders:
    • Researchers identified five HERVs associated with depression, schizophrenia, and bipolar disorder.
    • Specific HERV expression profiles are linked to increased susceptibility to these psychiatric conditions.
  2. Study Methodology:
    • The study involved analyzing large genetic datasets from tens of thousands of individuals, both with and without mental health conditions.
    • The team also examined autopsy brain samples from 800 individuals to understand how DNA variations linked to psychiatric disorders affect HERV expression.
    • Sequencing machines were used to read the individual letters of DNA, allowing scientists to piece together the complex human genome.
  3. Significant Associations:
    • Two HERV expressions were associated with schizophrenia risk.
    • One HERV expression was linked to both bipolar disorder and schizophrenia.
    • One HERV expression was associated with depression risk.
    • No HERV expressions were linked to hyperactivity disorder or autism spectrum conditions.

Implications of the Research:

Dr. Timothy Powell, co-senior author, emphasized that this study highlights the important role of ancient viral sequences in the human brain, suggesting they could influence genetic susceptibility to psychiatric disorders.

Dr. Rodrigo Duarte, first author, noted the substantial genetic component of psychiatric disorders and the relevance of the identified HERV sequences. While the exact mechanism by which these HERVs affect brain cells remains unclear, the findings suggest that regulating their expression is crucial for brain function.

This groundbreaking research not only reshapes our understanding of ‘junk DNA’ but also opens up new possibilities for the development of targeted treatments for psychiatric disorders by focusing on the regulation of these ancient viral sequences in the human genome.