Genome-wide analysis identifies novel shared loci between depression and white matter microstructure

Area of Science:

• Psychiatric Genetics
• Neuroimaging Genetics
• Computational Biology

Background:

• Depression is a heritable psychiatric disorder linked to white matter microstructure alterations.
• The shared genetic basis between depression and white matter integrity is not well understood.
• Previous research suggests a connection, but specific genetic overlaps require further investigation.

Purpose of the Study:

• To investigate the shared genetic architecture between major depressive disorder and white matter microstructure using large-scale genome-wide association study datasets.
• To identify specific genetic loci and genomic regions that jointly influence depression and white matter traits (fractional anisotropy and mean diffusivity).
• To explore the directionality and patterns of genetic effects and implicated biological pathways.

Main Methods:

• Utilized genome-wide association study (GWAS) data for depression (N=674,452) and white matter microstructure (N=33,224).
• Employed linkage disequilibrium score regression for global genetic correlations.
• Applied local analysis of [co]variant association and conjunctional false discovery rate analysis to identify shared variants and genomic regions.

Main Results:

• Significant local genetic correlations were found between depression and fractional anisotropy (37 regions) and mean diffusivity (59 regions).
• Identified 78 loci jointly associated with depression and FA, and 41 loci with depression and MD, including novel loci.
• Shared loci displayed mixed effect directions and distinct/overlapping hemispheric genetic patterns, implicating metabolism and regulation pathways.

Conclusions:

• Provides evidence for a mixed-direction shared genetic architecture between depression and white matter microstructure.
• Identified specific shared genetic loci and pathways that may underlie the relationship between depression and brain structure.
• Findings may inform the development of targeted interventions for improving white matter integrity and treating depression.