Mendelian randomization analyses for PCOS: evidence, opportunities, and challenges

Area of Science:

• Reproductive Endocrinology
• Genetic Epidemiology
• Metabolic Disorders

Background:

• Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder with complex etiology.
• Identifying etiological risk factors is crucial for effective prevention and treatment strategies.
• Mendelian randomization (MR) is a powerful genetic approach to investigate causal relationships.

Purpose of the Study:

• To review the application of Mendelian randomization (MR) in identifying causal risk factors for Polycystic Ovary Syndrome (PCOS).
• To summarize recent findings on associations between various exposures and PCOS using MR.
• To discuss the opportunities and challenges of using MR in PCOS research.

Main Methods:

• Utilizing genetic variants as instrumental variables to assess causal associations.
• Analyzing large-scale genetic data for exposure factors and Polycystic Ovary Syndrome (PCOS).
• Employing Mendelian randomization (MR) methodology to infer causality.

Main Results:

• MR studies have provided evidence for causal associations between PCOS and: anti-Müllerian hormone (AMH) levels, sex hormone-binding globulin (SHBG) levels, age at menopause, adiposity, insulin resistance (IR), depression, breast cancer, ovarian cancer, obsessive-compulsive disorder (OCD), and forced vital capacity (FVC).
• MR analyses did not support causal associations between PCOS and: type 2 diabetes mellitus (T2DM), coronary heart disease (CHD), stroke, anxiety disorder (AD), schizophrenia (SCZ), bipolar disorder (BIP), and offspring birth weight.

Conclusions:

• Mendelian randomization (MR) has elucidated specific causal pathways contributing to Polycystic Ovary Syndrome (PCOS) risk.
• The findings highlight key biological and lifestyle factors implicated in PCOS etiology.
• Further research is needed to address the challenges and maximize the potential of MR in understanding PCOS.