The Study On Relationship Between Polymorphism Of LRP5 Gene And BMD And Obesity Phenotype In Chinese Nuclear Families

Objective To explore the relationship between polymorphism of low density lipoprotein receptor related protein 5 gene and peak bone mineral density (BMD), body mass index (BMI), fat mass and lean mass in Chinese nuclear families.Methods 355 nuclear families composed of both parents and at least one healthy son aged from 20 to 40 with a total of 1077 individuals were recruited in the study. The LRP5 genotypes were detected by polymerase chain reaction/restriction fragment-length polymorphism (PCR-RFLP). BMD in lumbar spine 1-4 and left proximal femur (including femoral neck, trochanter and total hip), fat mass and lean mass were measured using dual energy X-ray absorptiometry. Meanwhile, height and weight were measured. The relationship between polymorphisms of LRP5 gene and peak BMD, BMI, fat mass and lean mass in young men were performed using the quantitative transmission disequilibrium test (QTDT) program. ANCOVA was performed to test whether any of the Q89R, N740N and A1330V polymorphisms of LRP5 were associated with BMD and BMI in father and mother groups.Results The 3 SNPs in LRP5 gene were not associated with peak BMD, BMI, fat mass and lean mass in young men. Association between A1330V polymorphism and BMD in lumbar spine and total hip was found in father group, Subjects with CC genotype had significantly higher BMD than those with CT/TT genotype in lumbar spine and total hip, A1330V explained 1.25% and 1.23% of the variation in lumbar spine and total hip BMD, respectively. N740N polymorphism was associated with trochanter BMD in mother group, In comparison with subjects with CC genotype, those with CT/TT genotype had significantly lower BMD values in trochanter, This polymorphism accounted for 1.17% of the variation in trochanter BMD.Q89R polymorphism was associated with BMI in mother group, In comparison with subjects with AA genotype, those with AG/GG genotype had significantly lower BMI values, This polymorphism accounted for 1.82% of the variation in BMI.Conclusions (1) Q89R, N740N and A1330V polymorphisms of LRP5 are not the quantitative trait loci underlying peak BMD, BMI, lean mass and fat mass in Chinese men. (2) N740N and A1330V polymorphisms of LRP5 gene may regulate BMD in stage of bone loss. Q89R polymorphism is the quantitative trait loci underlying BMI in Chinese women.