Association between estrogen receptor gene polymorphisms and curve severity of idiopathic scoliosis.

STUDY

DESIGN

Analysis of the estrogen receptor gene of girls with idiopathic scoliosis.

OBJECTIVES

To determine whether estrogen receptor gene polymorphisms correlate with curve severity of adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA: Studies suggest that idiopathic scoliosis is a familial condition and that curve progression is related to genetically determined factors, such as skeletal and sexual growth.

METHODS

A total of 304 girls with idiopathic scoliosis were followed until growth maturation. Height, arm span, menarcheal age, and age at growth maturation were recorded, and curve severity was measured using Cobb's method. The estrogen receptor gene, which contains polymorphic PvuII and XbaI sites, was amplified from lymphocyte deoxyribonucleic acid by polymerase chain reaction.

RESULTS

The mean maximum Cobb measurements for patients with genotypes XX and Xx were greater than for those with genotype xx (P = 0.002). The risk of curve progression, defined as progression of >5 degrees from initial evaluation, was higher with genotype Xx than with xx (P = 0.03). Patients with genotypes XX and Xx had a significantly higher risk for operative treatment than those with genotype xx (21.4%, 24.7% vs. 7.6%, P< 0.001). Growth examination around the time of the growth spurt revealed that the XbaI site polymorphism was also related to the age of growth maturation. The frequency of patients with growth maturation at >or=16 years was higher for genotypes XX and Xx than for genotype xx (33.3%, 29.9% vs. 16.8%, P= 0.013).

CONCLUSION

Our results suggest that the XbaI site polymorphism is associated with curve severity. DNA analysis may predict curve progression.