Age-related osteoporotic fracture is largely due to the universal reduction in bone strength that occurs with age. Bone density is the main component of bone strength. About 80% of variance in bone density is due to heritable factors that appear to be regulated by relatively few genes. Polymorphisms of the vitamin D receptor gene have been reported by one group, but unable to be confirmed by us, to be in linkage with both bone mineral density and bone turnover in whites. Blacks have higher bone density and lower bone turnover than whites but heritability and linkage of these phenotypes have not been studied. The overall goal is to establish that heritable factors account for a similar proportion of variance in bone strength in blacks and whites, and to identify genetic markers for bone strength and bone turnover. Our goal will be achieved by testing two hypotheses. Hypothesis 1: Heritability of bone strength and bone turnover in blacks are of the same order as that in whites. This will be tested in 200 black and 200 white healthy female sib-pairs, i.e. a total of 800 subjects. Quantitative phenotypes will include: bone mineral density at several skeletal sites, geometric and architectural variables at the hip, ultrasound transmission in the os calcis; concentration of biochemical markers of bone formation and resorption in blood and urine; serum concentration of calcium-regulating hormones; and calcium absorption. Heritability for these phenotypes will be calculated using the sib-pair model and compared between blacks and whites. Hypothesis 2: Variant alleles of a limited number of genes determine the heritability of bone strength and turnover and are responsible for the differences in bone strength and turnover between blacks and whites. This will be tested in the populations studied in hypothesis 1. Genotyping will use highly informative (dC-dA)n.(dG-dT)n microsatellites. Chromosomal regions closely flanking candidate genes, initially focusing on the vitamin D receptor gene, will be examined in detail. Later, genome-wide maps will be developed. Quantitative phenotypes will be examined for linkage to genotypes using a sib-pair analysis in which the genetic markers will be examined as identical-by-descent to determine those significantly shared above expectation. These protocols optimize the search for genetic markers of bone strength, which will provide the fundamental knowledge to develop new preventative and therapeutic regimens for age-related osteoporotic fracture.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR043476-04
Application #
2667817
Study Section
Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
Project Start
1995-03-31
Project End
2000-02-29
Budget Start
1998-03-01
Budget End
2000-02-29
Support Year
4
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005436803
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Chu, Kang; Cornetta, Kenneth G; Econs, Michael J (2008) Efficient and stable gene expression into human osteoclasts using an HIV-1-based lentiviral vector. DNA Cell Biol 27:315-20
Ichikawa, S; Johnson, M L; Koller, D L et al. (2006) Polymorphisms in the bone morphogenetic protein 2 (BMP2) gene do not affect bone mineral density in white men or women. Osteoporos Int 17:587-92
Ichikawa, Shoji; Koller, Daniel L; Johnson, Michelle L et al. (2006) Human ALOX12, but not ALOX15, is associated with BMD in white men and women. J Bone Miner Res 21:556-64
Peacock, Munro; Koller, Daniel L; Lai, Dongbing et al. (2005) Sex-specific quantitative trait loci contribute to normal variation in bone structure at the proximal femur in men. Bone 37:467-73
Koller, Daniel L; Ichikawa, Shoji; Johnson, Michelle L et al. (2005) Contribution of the LRP5 gene to normal variation in peak BMD in women. J Bone Miner Res 20:75-80
Peacock, Munro; Koller, Daniel L; Fishburn, Tonya et al. (2005) Sex-specific and non-sex-specific quantitative trait loci contribute to normal variation in bone mineral density in men. J Clin Endocrinol Metab 90:3060-6
Peacock, Munro; Koller, Daniel L; Hui, Siu et al. (2004) Peak bone mineral density at the hip is linked to chromosomes 14q and 15q. Osteoporos Int 15:489-96
Econs, Michael J; Koller, Daniel L; Hui, Siu L et al. (2004) Confirmation of linkage to chromosome 1q for peak vertebral bone mineral density in premenopausal white women. Am J Hum Genet 74:223-8
Koller, Daniel L; Peacock, Munro; Lai, Dongbing et al. (2004) False positive rates in association studies as a function of degree of stratification. J Bone Miner Res 19:1291-5
Koller, D L; White, K E; Liu, G et al. (2003) Linkage of structure at the proximal femur to chromosomes 3, 7, 8, and 19. J Bone Miner Res 18:1057-65

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