RAD51C and hypoparathyroidism-retardation-dysmorphism syndrome: Germline pathogenic variants (PVs) in RAD51C (OMIM 602774) and RAD51D (OMIM 602954) (RAD51C/D) are expected to cause homologous recombination deficiency (HRD) and genomic instability when there is biallelic inactivation, mainly through gene-specific loss of heterozygosity (gsLOH).