Vitiligo Causally Linked to Rheumatoid Arthritis, Type 1 Diabetes, and Alopecia Areata: Study

Bidirectional two-sample MR analyses were applied in the study to examine possible bidirectional causal relationships between vitiligo and all the autoimmune diseases. SMR and colocalization tests were further applied to detect common genetic loci that would account for the shared risks. The genetic method generated strong evidence without the common bias present in observational investigations.

Key Findings

Bidirectional Causality Between Vitiligo and RA

• RA raises the risk of vitiligo: IVW OR = 1.19, 95% CI: 1.05–1.13, p = 0.008

• Vitiligo raises the risk of RA: IVW OR = 1.08, 95% CI: 1.03–1.13, p < 0.001

Vitiligo raises the risk of other autoimmune diseases:

• Alopecia Areata (AA): IVW OR = 1.14, 95% CI: 1.04–1.26, p = 0.008

• Type 1 Diabetes Mellitus (T1DM): IVW OR = 1.14, 95% CI: 1.06–1.23, p < 0.001

Genetic loci shared:

SMR and colocalization tests identified three shared genes between RA and vitiligo:

• FCRL3 (Fc Receptor-Like 3)

• FADS1 (Fatty Acid Desaturase 1)

• FADS2 (Fatty Acid Desaturase 2)

These could potentially function as future therapeutic or diagnostic targets, indicating a common autoimmune mechanism.

This study presents genetic evidence that vitiligo is causally linked with RA, T1DM, and AA, with reciprocal risk elevation particularly between vitiligo and RA. Shared susceptibility genes also strengthen the notion of shared autoimmune mechanisms and provide a new area for multi-disease treatment and drug development.

Reference:

Huang, J., Jiang, L., Hu, Y., Fu, C., Zhang, K., Wen, Y., Zhou, S., Huang, J., Chen, J., & Zeng, Q. (2025). Association of vitiligo with autoimmune disorders: A bidirectional two‐sample and summary‐based Mendelian randomization study. Journal of Cosmetic Dermatology, 24(6). https://doi.org/10.1111/jocd.70211