Association of FBN1 polymorphism with susceptibility of adolescent idiopathic scoliosis: a case control study

Abstract

Objective: Fibrillin-1 (FBN1) is an extracellular matrix glycoprotein essential to the structural component of microfibrils and FBN1 gene polymorphisms can be associated with adolescent idiopathic scoliosis (AIS) susceptibility. This study aimed to evaluate the potential role of the FBN1 rs12916536 polymorphism in AIS development or severity and the variation in Cobb angle in relation to patient’s characteristics.

Methods: DNA from 563 subjects (185 AIS patients and 378 controls) were genotyped using a validated TaqMan allelic discrimination assay. A multivariate logistic regression model evaluated the association between polymorphism and AIS, using the adjusted odds ratios (OR) with their respective 95% confidence intervals (95% CI). A linear regression analysis evaluated the variation in Cobb angle according to the patient’s age and body mass index (BMI).

Results: Among the AIS group there was a predominance of females (12:1), low or normal BMI (90%), 58% had a Cobb angle greater than 45° and 74% were skeletally mature. Age was a risk factor (4-fold) for curve progression higher than BMI (P<0.001). The allelic frequency of the rs12916536 G>A polymorphism was 40% in controls and 31% in AIS cases; and this difference was statistically significant (P=0.004). FBN1 rs12916536 GA+AA genotypes were associated with a lower risk of AIS susceptibility (OR=0.58 and 95% CI=0.35–0.98), after adjustment for age, sex and BMI. However, no significant differences were detected in polymorphism distribution with the severity of the disease (Cobb <45° or≥45°).

Conclusion: Age was a risk factor for progression of the scoliotic curve and FBN1 rs12916536 polymorphism a protective factor for AIS susceptibility.