PPP3R1 and familial isolated hyperparathyroidism: Interestingly, one study has reported a 1.7 Mb interval of significant genetic linkage for FIHP on chromosome 2p13.3‐14, although conservative mutations involving the protein phosphatase 3 regulatory subunit B alpha (PPP3R1) and prokineticin receptor 1 (PROKR1) genes, which are in this interval, were not identified (Warner et al., 2006).