Genetic contributions to bone mineral density (BMD) and bone turnover are well known.
In the present study, we analyzed the relationship between polymorphism of parathyroid
hormone (PTH)/PTH-related peptide (PTHrP) receptor gene existing in exon M7 and the
clinical characteristics of primary hyperparathyroidism (pHPT). PTH/PTHrP receptor
genotypes were analyzed in 92 pHPT patients by direct sequence to determine whether
nucleotide 1417 of the cDNA was C or T. BMD levels at the lumbar spine and at the
radius before and one year after parathyroidectomy, as well as serum levels of calcium,
phosphorus, alkaline phosphatase (ALP) and intact PTH were measured. Although there
were no significant differences in serum levels of calcium, phosphorus and intact
PTH, ALP was significantly lower in the CT genotype compared with the TT genotype.
BMD level at the radius was significantly higher in the CT genotype than in the CC
genotype. Moreover, an increase in radial BMD one year after parathyroidectomy was
significantly less in CT genotype than two other genotypes (CC, TT). The present study
is the first to indicate that the polymorphism of PTH/PTHrP receptor gene is closely
related to the extent of bone mass reduction in pHPT and that this polymorphism would
be one of the genetic factors responsible for the severity of the pathological state
of pHPT.
Key words
PTH/PTHrP Receptor - Polymorphism - Bone Mineral Density - Primary Hyperparathyroidism
