Association of collagen type 1 alpha 1 gene polymorphism with bone densityin early childhood

Osteoporosis is a disease characterized by the development of nontraumatic fractures, most commonly in the vertebrae of elderly women. Approximately 5 00,000 elderly women in the United States are newly diagnosed with vertebra l fractures every year, as the compressive strength of the vertebra, mainly determined by the density of cancellous bone and its cross-sectional area, declines with age. A recent study in women suggested that a polymorphism i n the Spl binding site of the collagen type I gene (COLIA1) was related to decreased vertebral bone mass and vertebral fractures. Determining the phen otypic trait(s) responsible for this relationship and whether this associat ion is manifested in childhood would further define the structural basis fo r decreased bone mass and help identify children "at risk" for fractures la ter in life. We therefore studied the COLIA1 gene polymorphism and measurem ents of the size and the density of vertebral bone in 109 healthy, prepuber tal girls. On average, 22 girls with the Ss genotype and one girl with the ss genotype had 6.7% and 49.4% lower cancellous bone density in the vertebr ae than girls with the SS genotype. In contrast, there was no association b etween the size of the vertebrae and the COLIA1 genotypes.