The prevalence of germline HRR gene mutations was reported in up to 16.2% of patients with metastatic PC (compared with 3.8% and 8.9% in low-risk and high-risk localized PC), and the most frequently affected genes were BRCA2 (5.4%), CHEK2 (1.9%), ATM (1.6%), BRCA1 (0.9%), RAD51D (0.4%), PALB2 (0.4%), ATR (0.3%), PMS2 (0.3%), NBN (0.3%), and BRIP1 (0.2%) [90]. Here, RAD51D is linked to pachyonychia congenita.