The causal relationship between vitiligo and autoimmune thyroid diseases: A bidirectional two-sample Mendelian...

Area of Science:

• Genetics
• Immunology
• Dermatology
• Endocrinology

Background:

• Vitiligo is an autoimmune skin disorder causing depigmentation and impacting quality of life.
• Autoimmune thyroid diseases (AITDs) involve immune system dysregulation attacking the thyroid gland.
• Previous studies suggested an association between vitiligo and AITDs, but causality remained unconfirmed.

Purpose of the Study:

• To investigate the bidirectional causal relationship between vitiligo and AITDs using genetic data.
• To assess if genetic predisposition to vitiligo increases AITD risk and vice versa.

Main Methods:

• A two-sample Mendelian randomization (MR) analysis was performed.
• Genome-wide association study summary statistics from European populations were utilized.
• Inverse variance weighted method was the primary analysis, with sensitivity analyses for robustness.

Main Results:

• Forward MR indicated a causal link between vitiligo and autoimmune thyroiditis (AIT), autoimmune hyperthyroidism (AIH), and Graves' disease (GD).
• Reverse MR showed a causal association between AIT and vitiligo.
• No significant causal relationship was found between AIH or GD and vitiligo.

Conclusions:

• Genetic evidence supports a causal association between vitiligo susceptibility and increased risk of AITDs.
• A causal link exists between AIT susceptibility and increased risk of vitiligo.
• No similar genetic causal association was identified for autoimmune hyperthyroidism or Graves' disease with vitiligo.