Association of a single nucleotide polymorphism in growth differentiate factor 5 with congenital dysplasia of the hip: a case-control study

INTRODUCTION Congenital dysplasia of the hip is an abnormal seating of the femoral head in the acetabulum, mainly caused by shallow acetabulum and lax joint capsule. Genetic factors play a considerable role in the pathogenesis of congenital dysplasia of the hip. The gene growth differentiate factor 5 (GDF5) has been implicated in skeletal development and joint morphogenesis in humans and mice. A functional single nucleotide polymorphism (SNP) in the 5'-untranslated region of GDF5 (rs143383) was reported to be associated with osteoarthritis susceptibility. As a key regulator in morphogenesis of skeletal components and soft tissues in and around the joints, GDF5 may be involved in the aetiology and pathogenesis of congenital dysplasia of the hip. Our objective is to evaluate if the GDF5 SNP is associated with congenital dysplasia of the hip in people of Han Chinese origin. METHODS The GDF5 SNP was genotyped in 338 children with congenital dysplasia of the hip and 622 control subjects. RESULTS The SNP was significantly associated with congenital dysplasia of the hip (p = 0.0037; odds ration (OR) = 1.40; 95% confidence interval (CI) = 1.11 to 1.75). A significant difference was detected in female samples when stratified by gender (p = 0.0053; OR = 1.46; 95% CI = 1.21 to 1.91), and in hip dislocation when stratified by severity (p = 0.0078; OR = 1.43; 95% CI = 1.11 to 1.85). CONCLUSIONS Our results indicate that GDF5 is important in the aetiology of congenital dysplasia of the hip. To the authors' knowledge this is the first time that a definite association with the congenital dysplasia of the hip susceptibility has been detected.