Clinically, most men in the discovery sample had low-risk PC (3,639; 70%) and/or features of low-risk, low-volume disease: GG1 (4,819; 92%), 1–2 positive biopsy cores (4,113; 79%), and a median PSA at diagnosis of 5 ng/mL. This evidence concerns the gene KLK3 and pachyonychia congenita.