Do the COL1A1 and Taq 1 vitamin D receptor polymorphisms have a role in identifying individuals at risk of developing osteoporosis?

McClean E, Archbold GP, Taggart HM.

Department of Clinical Biochemistry, Belfast City Hospital, Lisburn Road, Belfast BT9 7AB.

The distribution of the Taq 1 polymorphism in the vitamin D receptor (VDR) gene and the MSc 1 polymorphism in the collagen 1 alpha 1 (COL1A1) gene were studied in 266 female and 55 male patients attending an osteoporosis clinic. Allele frequency in control (T- or Z-score >-1.0) and osteoporotic (T- or Z-scores <-2.5) groups were compared using Chi squared tests.

No differences were found between the 2 groups with either of the polymorphisms. When allele frequency was compared in patients with and without history of fracture, no differences were found in the frequency of the COL1A1 alleles.

However there were significantly more fracture patients, who had been previously treated with corticosteroids for other conditions, carrying the T allele of the VDR polymorphism (X2 = 5.65, p>0.01<0.02).

In conclusion, neither of these polymorphisms aid in the prediction of osteoporosis but the VDRT allele may carry an increased fracture risk in patients who require corticosteroid treatment.