Association analyses of vitamin D-binding protein gene with compression strength index variation in Caucasian nuclear families.
This study was conducted to test whether there exists an association between vitamin D-binding protein (DBP) gene and compression strength index (CSI) phenotype. Candidate gene association analyses were conducted in total sample, male subgroup, and female subgroup, respectively. Two single-nucleotide polymorphisms (SNPs) with significant association results were found in males, suggesting the importance of DBP gene polymorphisms on the variation in CSI especially in Caucasian males.


BACKGROUND
CSI of the femoral neck (FN) is a newly developed phenotype integrating information about bone size, body size, and bone mineral density. It is considered to have the potential to improve the performance of risk assessment for hip fractures because it is based on a combination of phenotypic traits influencing hip fractures rather than a single trait. CSI is under moderate genetic determination (with a heritability of approximately 44% found in this study), but the relevant genetic study is still rather scarce.


METHODS
Based on the known physiological role of DBP in bone biology and the relatively high heritability of CSI, we tested 12 SNPs of the DBP gene for association with CSI variation in 405 Caucasian nuclear families comprising 1,873 subjects from the Midwestern US. Association analyses were performed in the total sample, male and female subgroups, respectively.


RESULTS
Significant associations with CSI were found with two SNPs (rs222029, P = 0.0019; rs222020, P = 0.0042) for the male subgroup. Haplotype-based association tests corroborated the single-SNP results.


CONCLUSIONS
Our findings suggest that the DBP gene might be one of the genetic factors influencing CSI phenotype in Caucasians, especially in males.
Xu
X-H
XH
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
Xiong
D-H
DH
Liu
X-G
XG
Guo
Y
Y
Chen
Y
Y
Zhao
J
J
Recker
R R
RR
Deng
H-W
HW
D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000235:genetics / Q000502:physiology; D019245:Compressive Strength / Q000502:physiology*; D005260:Female; D005272:Femur Neck / Q000502:physiology; D056726:Genetic Association Studies / Q000379:methods; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D012727:Sex Characteristics; D014809:Vitamin D-Binding Protein / Q000235:genetics*; D055815:Young Adult
D014809:Vitamin D-Binding Protein