The response to PARP inhibitors and platinum-based chemotherapy can be predicted by ADP-ribosylation (ADPRylation), which is also catalyzed by PARP enzymes, independently of the BRCA1/2 or homologous recombination deficiency (HRD) status [34]. This evidence concerns the gene PARP1 and hypoparathyroidism-retardation-dysmorphism syndrome.