Abstract
Introduction
This study was to investigate the association of developmental dysplasia of the hip (DDH) and primary protrusion acetabuli (PPA) with Vitamin D receptor polymorphisms TaqI and FokI and oestrogen receptor polymorphisms Pvu II and XbaI.
Methods
45 patients with DDH and 20 patients with PPA were included in the study. Healthy controls (n=101) aged 18-60 years were recruited from the same geographical area. The control subjects had a normal acetabular morphology based on a recent pelvic radiograph performed for an unrelated cause. DNA was obtained from all the subjects from peripheral blood. Genotype frequencies were compared in the three groups. The relationship between the genotype and morphology of the hip joint, severity of the disease, age at onset of disease and gender were examined.
Results
The oestrogen receptor XbaI wild-type genotype (XX, compared with Xx and xx combined) was more common in the DDH group (55.8%) than controls (37.9%), though this just failed to achieve statistical significance (p=0.053, odds ratio=2.1, 95% CI=0.9-4.6). In the DDH group, homozygosity for the mutant TaqI Vitamin D receptor t allele was associated with higher acetabular index (Mann-Whitney U-test, p= 0.03). Pvu II pp oestrogen receptor genotype was associated with low centre edge angle (p=0.07).
Conclusion
This study suggests a possible correlation between gene polymorphism in the oestrogen and vitamin D receptors and susceptibility to, and severity of DDH. The TaqI vitamin D receptor polymorphisms may be associated with abnormal acetabular morphology leading to DDH while the XbaI oestrogen receptor XX genotype may be associated with increased risk of developing DDH. No such correlations were found in the group with PPA.
