COLIA gene in osteoporosis

COLIA1 and COLIA2 code for type I collagen (the major protein in bones) (1)

A point polymorphism (G->T) in a regulatory sequence for the COLIA1 gene was found to be significantly linked with risk for osteoporosis. The polymorphism is at a binding site for the transcription factor Sp1 (2)

• polymorphism affecting the transcription factor Sp1 binding site has been reported commonly in Caucasian population but rare in the Africans and the Chinese (2)

The wild type sequence is termed S (G instead of T). The polymorphic sequence is termed s (T instead of G).

Rank order of bone density in women is: SS > Ss > ss

Over half of patients with severe osteoporosis and vertebral fractures are ss or Ss, compared with a quarter of controls.

The risk of vertebral fractures in ss or Ss patients is almost three times higher than SS patients.

Reference:

• (1) Ralston SH. Genetics of osteoporosis. Proc Nutr Soc. 2007;66(2):158-65
• (2) Williams FM, Spector TD. Recent advances in the genetics of osteoporosis. J Musculoskelet Neuronal Interact. 2006;6(1):27-35.