RAD51C and hypoparathyroidism-retardation-dysmorphism syndrome: Next to BRCA1 and BRCA2, PVs in other HR-related genes such as PALB2, RAD51C and RAD51D as well as epigenetic silencing of BRCA1 and RAD51C via hypermethylation of the gene promotor have been shown to lead to HR deficiency (HRD) [4].