BRCA1 and hypoparathyroidism-retardation-dysmorphism syndrome: A systematic review included 60 studies with 21,842 participants who reported that the main contribution to homologous recombination deficiency (HRD) was through BRCA2, BRCA1, and ATM, followed by FANC genes, CHEK2, and PALB2 in PDAC patients (Casolino et al., 2021).