SRD5A2 and pachyonychia congenita: We hypothesized that four single nucleotide polymorphisms (SNPs) in three critical androgen-regulating genes: 3-beta-hydroxysteroid dehydrogenase (HSD3B1), solute carrier organic ion (SLCO2B1), and steroid 5-α-reductase type 2 (SRD5A2) [2,3,4,5,6], contribute, individually and in aggregate, to PC outcomes.