title: Quantitative trait locus on chromosome X affects bone loss after maturation in mice.
abstract: Genetic programming is known to affect the peak bone mass and bone loss after maturation. However, little is known about how polymorphic genes on chromosome X (Chr X) modulate bone loss after maturation. We previously reported a quantitative trait locus (QTL) on Chr X, designated Pbd3, which had a suggestive linkage to bone mass, in male SAMP2 and SAMP6 mice. In this study, we aimed to clarify the effects of Pbd3 on the skeletal phenotype. We generated a congenic strain, P2.P6-X, carrying a 45.6-cM SAMP6-derived Chr X interval on a SAMP2 genetic background. The effects of Pbd3 on the bone phenotype were determined by microcomputed tomography (microCT), whole-body dual-energy X-ray absorptiometry (DXA), serum bone turnover markers, and histomorphometric parameters. Both the bone area fraction (BA/TA) on microCT and whole-body DXA revealed reduced bone loss in P2.P6-X compared with that in SAMP2. The serum concentrations of bone turnover markers at 4 months of age were significantly lower in P2.P6-X than in SAMP2, but did not differ at 8 months of age. These results were observed in female mice, but not in male mice. In conclusion, a QTL within a segregated 45.6-cM interval on Chr X is sex-specifically related to the rate of bone loss after maturation.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Sakyo, Kyoto 606-8507, Japan.
authors.forename: Shuzo
authors.initials: S
authors.lastname: Okudaira
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Shimizu
authors.forename: Bungo
authors.initials: B
authors.lastname: Otsuki
authors.forename: Rika
authors.initials: R
authors.lastname: Nakanishi
authors.forename: Akira
authors.initials: A
authors.lastname: Ohta
authors.forename: Keiichi
authors.initials: K
authors.lastname: Higuchi
authors.forename: Masanori
authors.initials: M
authors.lastname: Hosokawa
authors.forename: Tadao
authors.initials: T
authors.lastname: Tsuboyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000235:genetics*; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000378:metabolism*; D005260:Female; D005838:Genotype; D008297:Male; D051379:Mice; D020297:Mice, Congenic; D040641:Quantitative Trait Loci; D014960:X Chromosome / Q000235:genetics*; D055114:X-Ray Microtomography
chemical_list: D015415:Biomarkers