Patients with biallelic inactivation mutations in the following genes: RAD51 paralog D (RAD51D) (n = 4), BRCA1-associated RING domain protein 1 (BARD1) (n = 3), Chromosome 19 open reading frame 40 (C19orf40) (n = 1) and MRE11 homolog A (MRE11A) (n = 1) are all predicted as HRD, suggesting these genes, especially BARD1 and RAD51D inactivation can be genetic basis of human HRD. The gene discussed is RAD51D; the disease is hypoparathyroidism-retardation-dysmorphism syndrome.