With a hypercalcemic family member, mutation detection rate in FHH rose to seven of eight (87%), whereas only one of nine sporadic cases was positive, and none of the three FIHP cases had detectable CASR mutations.
FIHP phenotypes have been associated with mutant MEN1 and calcium-sensing receptor (CASR) genotypes and, very recently, with mutation in the newly identified HRPT2 gene.
Nonsyndromic PHPT, which may be hereditary and referred to as familial isolated hyperparathyroidism, may also be due to MEN1, CDC73 or calcium-sensing receptor (CASR) mutations.
A subset of patients carry germline mutations in genes such as MEN1 (multiple endocrine neoplasia type 1), HRPT2 (hyperparathyroidism 2), and CASR (calcium-sensing receptor) predisposing to syndromic forms of PHPT or familial isolated hyperparathyroidism (FIHP).
Molecular genetics in primary hyperparathyroidism: the role of genetic tests in differential diagnosis, disease prevention strategy, and therapeutic planning. A 2017 update.