Vitamin D binding protein genotype and osteoporosis.

Osteoporosis is a bone disease leading to an increased fracture risk. It is considered a complex multifactorial genetic disorder with interaction of environmental and genetic factors. As a candidate gene for osteoporosis, we studied vitamin D binding protein (DBP, or group-specific component, Gc), which binds to and transports vitamin D to target tissues to maintain calcium homeostasis through the vitamin D endocrine system.

The catechol-O-methyltransferase Met158 low-activity allele and association with nonvertebral fracture risk in elderly men.

Context: Because sex steroids play an important role in bone development, variants in genes encoding proteins involved in estrogen synthesis and metabolism could contribute to interindividual variation in bone parameters and fracture risk. An example is catechol-O-methyltransferase (COMT), an estrogen-degrading enzyme involved in inactivation of catechol-estrogens. Its gene contains a functional valine to methionine substitution at codon 158.

Vitamin D receptor gene haplotype is associated with body height and bone size.

Context: Adult stature is a complex genetic trait. The vitamin D endocrine system has pleiotropic effects on several physiological processes, especially on skeletal metabolism. We recently identified promoter and 3'-untranslated region (UTR) haplotype alleles that influence vitamin D receptor (VDR) mRNA expression.

Promoter and 3'-untranslated-region haplotypes in the vitamin d receptor gene predispose to osteoporotic fracture: the rotterdam study.

Polymorphisms of the vitamin D receptor gene (VDR) have been shown to be associated with several complex diseases, including osteoporosis, but the mechanisms are unknown and study results have been inconsistent. We therefore determined sequence variation across the major relevant parts of VDR, including construction of linkage disequilibrium blocks and identification of haplotype alleles. We analyzed 15 haplotype-tagging SNPs in relation to 937 clinical fractures recorded in 6,148 elderly whites over a follow-up period of 7.