The Association Between BMP-2, UQCC1 and CX3CR1 Polymorphisms and the Risk of Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH) is a complicated skeletal disease ranging from subluxation to complete dislocation of the hip as a result of insufficient development of the acetabulum and femur. To date, numerous genes such as C-X3-C motif chemokine receptor 1 (CX3CR1), ubiquinol-cytochrome c reductase complex assembly factor 1 (UQCC1) and growth/differentiation factor 5 (GDF5), have been investigated to elucidate the underlying genetic etiology. Turkish population is one of the communities where DDH patients frequently observed, but almost no study has been conducted to elucidate the genetic etiology. In our study, we aimed to investigate the polymorphism of CX3CR1 rs3732378 and UQCC1 rs6060373, which have been shown to be associated with DDH in different populations. In addition, we aimed to investigate the BMP-2 rs235768 polymorphism which has not been investigated in the etiology of DDH.

Overall, 168 subjects (68 participants in the patient group, 100 participants in the control group) were investigated. The participants with following evidence and symptoms were excluded from the two groups: any systemic syndrome, another congenital anomaly, hereditary diseases, breech presentation, history of oligohydramnios, swaddling and high birth weight (> 4000 g). 3 single-nucleotide polymorphisms (SNP) were examined by qRT-PCR method.

For CX3CR1 rs3732378 polymorphism, significant differences were observed in genotypes and allele frequencies (p < 0.0001). This condition was associated with a 12-fold increased risk in recessive modeling and 75-fold increased risk in dominant modeling. There was no significant relationship between DDH and the other two polymorphisms.

Our work is the first study to investigate DDH and genetic polymorphisms in Turkish population where DDH is observed quite frequently. It is also the first study to investigate the relationship between BMP-2 rs235768 polymorphism and DDH. Our study revealed a clear relationship between CX3CR1 rs3732378 polymorphism and DDH in Turkish population.