Genetically predicted ankylosing spondylitis is causally associated with psoriasis

Area of Science:

• Rheumatology
• Genetics
• Epidemiology

Background:

• Observational studies suggest a link between ankylosing spondylitis (AS) and psoriasis.
• The precise causal relationship between AS and psoriasis is not well-established.

Purpose of the Study:

• To investigate the bidirectional causal associations between ankylosing spondylitis and psoriasis using Mendelian randomization.
• To determine if AS causally influences psoriasis risk and vice versa.

Main Methods:

• Two-sample Mendelian randomization analysis was employed.
• Genome-wide association study (GWAS) single-nucleotide polymorphisms (SNPs) served as instrumental variables.
• Sensitivity analyses were performed to assess pleiotropy and heterogeneity.

Main Results:

• Genetically predicted risk of ankylosing spondylitis showed a positive causal effect on psoriasis risk (OR = 1.009).
• No significant causal effect of psoriasis on ankylosing spondylitis risk was detected (OR = 1.183).
• Sensitivity analyses confirmed the robustness of the findings, ruling out significant pleiotropy or heterogeneity.

Conclusions:

• Ankylosing spondylitis has a positive causal effect on the risk of developing psoriasis.
• These findings contribute to understanding the etiological relationship between AS and psoriasis in European ancestry individuals.