Association of the D repeat polymorphism in the ASPN gene with developmental dysplasia of the hip: a case-control study in Han Chinese
- Equal contributors
1 The Center of Diagnosis and Treatment for Joint Disease, Drum Tower Hospital Affiliated to Medical School of Nanjing University, Zhongshan Road 321, Nanjing 210008, Jiangsu, PR China
2 Laboratory for Bone and Joint Diseases, Model Animal Research Center, Nanjing University, Xuefu Road 12, Nanjing 210008, Jiangsu, PR China
3 Center of Diagnosis and Treatment for Congenital Dysplasia of Hip, Kang'ai Hospital, Nanchang Road 32, Nanjing 210008, Jiangsu, PR China
4 Department of Pathology, Medical School of Nanjing University, Hankou Road 22, Nanjing 210093, Jiangsu, PR China
5 Laboratory for Bone and Joint Diseases, Center for Genomic Medicine, RIKEN, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
Arthritis Research & Therapy 2011, 13:R27 doi:10.1186/ar3252Published: 17 February 2011
Developmental dysplasia of the hip (DDH) is a common skeletal disease, which is characterized by abnormal seating of the femoral head in the acetabulum. Genetic factors play a considerable role in the etiology of DDH. Asporin (ASPN) is an ECM protein which can bind to TGF-β1 and sequentially inhibit TGF-β/Smad signaling. A functional aspartic acid (D) repeat polymorphism of ASPN was first described as an osteoarthritis-associated polymorphism. As TGF-β is well known as an important regulator in the development of skeletal components, ASPN may also be involved in the etiology of DDH. Our objective is to evaluate whether the D repeat polymorphism of ASPN is associated with DDH in Han Chinese.
The D repeat polymorphism was genotyped in 370 DDH patients and 445 control subjects, and the allelic association of the D repeat was examined.
From D11 to D18, eight alleles were identified. D13 allele is the most common allele both in control and DDH groups, the frequencies are 67.3% and 58.1% respectively. In the DDH group, a significantly higher frequency of the D14 allele and significantly lower frequency of D13 was observed. The association of D14 and D13 was found in both females and males after stratification by gender. There was no significant difference in any other alleles we examined.
Our results show an obvious association between the D repeat polymorphism of ASPN and DDH. It indicates that ASPN is an important regulator in the etiology of DDH.