Polymorphism of the collagen type Iα1 gene and ethnic differences in hip-fracture rates

To the Editor: The susceptibility to osteoporotic fracture varies markedly among ethnic groups, and the differences are partly independent of differences in bone mass. For example, hip fractures are rare in elderly black Africans and in Asians, even though bone-density values in these people are similar to those in age-matched white people.1 Genetic factors, which may include genetic differences in bone quality, are important in the pathogenesis of osteoporosis. Although the molecular mechanisms that underlie these differences are unclear, Uitterlinden et al.2 recently reported that a guanosine–thymidine substitution in a regulatory region of the collagen type Iα1 gene (COLIA1) 3 predicted . . .