Shared Genetic Background between Parkinson's Disease and Schizophrenia: A Two-Sample Mendelian Randomization Study

Area of Science:

• Neurogenetics
• Psychiatric Genetics
• Complex Disease Etiology

Background:

• Parkinson's disease (PD) and schizophrenia share overlapping symptoms, including psychosis in PD and motor deficits in schizophrenia.
• Few studies have investigated the bidirectional genetic relationship between PD and schizophrenia.

Purpose of the Study:

• To determine if genetic variants associated with increased PD risk influence schizophrenia susceptibility.
• To investigate if genetic variants linked to schizophrenia alter the risk of developing PD.

Main Methods:

• Two-sample Mendelian randomization (TSMR) analysis using large-scale genome-wide association study (GWAS) summary statistics.
• Utilized summary statistics for PD and schizophrenia GWAS to identify genetic instruments.

Main Results:

• A significant positive association was found between genetically predicted PD risk and schizophrenia risk (OR = 1.10, p = 3.49 × 10^-5).
• Sensitivity analyses confirmed the robustness of the PD to schizophrenia association.
• No significant association was observed between genetic risk for schizophrenia and PD risk.

Conclusions:

• Increased genetic risk for PD is associated with an elevated risk of schizophrenia.
• This finding supports an intrinsic link for psychotic symptoms in PD, independent of medication or environmental factors.
• Further research into shared genetic architecture and comorbidities between PD and schizophrenia is warranted.