Vitamin D binding protein gene in male osteoporosis: association of plasma DBP and bone mineral density with (TAAA)(n)-Alu polymorphism in DBP.
Vitamin D binding protein (DBP) is a major carrier protein for the vitamin D metabolites, but may also play an important role in osteoclast differentiation. Polymorphisms of the DBP gene have been reported, including (TAAA)(n)-Alu repeat polymorphisms downstream of intron 8. We have examined the relationship between polymorphisms of the DBP gene and bone mineral density (BMD) and vertebral fractures in a group of 26 men with vertebral fractures but no underlying secondary cause of osteoporosis (median age 64, ages 27-72 years) and 21 male control subjects (median age 65, ages 40-77 years). There was no apparent effect of DBP phenotype on BMD, but there was a relationship between certain genotypes of (TAAA)(n)-Alu repeats and reduced BMD and vertebral fracture. Lumbar spine and femoral neck BMD were significantly lower in men with 10/8 genotype than 10/10 genotype (P < 0.05). Furthermore, the predominant genotype in men with vertebral fractures was 10/8, whereas the most common genotype in control subjects was 10/10 (odds ratio 56; 95% confidence interval 7-445). Plasma DBP was higher in men with 10/8 genotype than those with 10/10 genotype (P < 0.05), and patients with vertebral fractures were found to have higher levels than control subjects (P < 0.0005). Although our study is small because of the relative rarity of idiopathic osteoporosis in men, the results suggest that (TAAA)(n)-Alu polymorphism may have an important effect on plasma levels of DBP, bone density and fracture risk in men.
Papiha
S S
SS
Department of Clinical Biochemistry and Metabolic Medicine, The Medical School, University of Newcastle, Newcastle upon Tyne NE2 4HH, UK.
Allcroft
L C
LC
Kanan
R M
RM
Francis
R M
RM
Datta
H K
HK
D000328:Adult; D000368:Aged; D020087:Alu Elements; D001483:Base Sequence; D015519:Bone Density; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D008969:Molecular Sequence Data; D010024:Osteoporosis / Q000235:genetics*; D011110:Polymorphism, Genetic; D016103:Spinal Fractures / Q000097:blood / Q000235:genetics; D014809:Vitamin D-Binding Protein / Q000097:blood / Q000235:genetics*
D014809:Vitamin D-Binding Protein