Comparison of Risk Allele Frequencies of Psoriasis-Associated Single-Nucleotide Polymorphisms in Different Population Groups.

Background: The prevalence of psoriasis differs by population, and it appears to be more common among Europeans than in East Asians. Recent genome-wide association studies (GWAS) have identified alleles that increase the risk of psoriasis, and these alleles may present different frequencies in different geographic regions.

Objective: We aimed to gain insights into the causes of differences in disease frequencies according to populations and the factors affecting prevalence and pattern differences.

Methods: We collected a total of 147 psoriasis-associated single-nucleotide polymorphisms (SNPs) from the GWAS catalog and compared the allele frequency differences in 27 populations using public population frequency in the 1000 Genomes Project phase 3 (n=2,504) and the Korean Reference Genome Database (n=1,722). Additionally, we calculated the composited genetic risk scores across the population groups.

Results: There were distinct patterns of allele frequencies in different population groups. In many cases, East Asians exhibited allele frequencies opposite to that of Europeans. The genetic risk score was higher in Europeans (average: 0.487) and Americans (average: 0.492) than in East Asians (average: 0.471). The prevalence of psoriasis correlated with the average genetic risk score of the population.

Conclusion: We observed a difference in the allele frequencies of psoriasis-associated SNPs between the studied populations. This result suggests that the difference in the prevalence of psoriasis between population groups can be interpreted to some extent by the genotype.