Cerebral small vessel disease increases risk for epilepsy: a Mendelian randomization study

Area of Science:

• Neurology
• Genetics
• Epidemiology

Background:

• Cerebral small vessel disease (CSVD) and epilepsy association is known, but causality is unclear.
• Investigating the causal link between CSVD and epilepsy is crucial for understanding disease mechanisms.
• Previous research suggests a potential link, necessitating further investigation into directionality.

Purpose of the Study:

• To investigate the causal relationship between cerebral small vessel disease (CSVD) and epilepsy using Mendelian randomization.
• To determine if genetic susceptibility to CSVD influences epilepsy risk.
• To explore the specific types of CSVD and epilepsy involved in the causal link.

Main Methods:

• Bidirectional two-sample Mendelian randomization (MR) analysis.
• Inclusion of five CSVD dimensions: small vessel ischemic stroke (SVS), intracerebral hemorrhage (ICH), white matter damage (WMH, fractional anisotropy, mean diffusivity), lacunar stroke, and cerebral microbleeds.
• Analysis of epilepsy encompassing focal and generalized types, with Inverse Variance Weighted (IVW) as the primary method and multivariable MR for pleiotropy control.

Main Results:

• Genetic susceptibility to SVS, fractional anisotropy, mean diffusivity, and lacunar stroke significantly increased epilepsy risk (FDR-adjusted P < 0.05).
• The association was primarily observed in focal epilepsy, not generalized epilepsy.
• Findings were robust in multivariable MR analysis, adjusting for vascular risk factors.

Conclusions:

• Genetic factors contributing to CSVD independently elevate the risk of developing epilepsy, especially focal epilepsy.
• Diffusion tensor imaging metrics may aid in identifying CSVD patients at high risk for epilepsy.
• Effective management of CSVD could be a key strategy in reducing the overall incidence of epilepsy.