Evidence of gene-gene interaction in hidradenitis suppurativa: a nationwide registry study of Danish twins.

This twin study was substantially larger and employed a more valid phenotype than previous studies. Genetics account for the majority of HS susceptibility, and HS is most likely caused by gene-gene interactions rather than monogenetic mutations or solely additive genetic factors. New approaches aimed at assessing potential interactions at a single-nucleotide polymorphism (SNP)-SNP level should be implemented in future HS genome-wide association studies.