Association of single nucleotide polymorphisms (SNPs) in leptin re-ceptor gene with knee osteoarthritis in the Ningxia Hui population

To investigate the association between primary knee osteoarthritis (OA) and single nucleotide polymorphism (SNP) (A668G) of leptin receptor gene (LEPR) in the Ningxia Hui population. A case-control association study has been adopted in this thesis. The polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis were performed to investigate the SNP of A668G site within LEPR from 148 patients with knee OA and 155 controls (asymptomatic and radiographically negative) with matched age and gender among Ningxia Hui population. In addition, genotypes of LEPR were verified by direct sequence analysis on PCR products. The result indicates that allele and genotype frequencies (P=0.024 and 0.008, respectively) in LEPR SNP A668G were significantly different in the knee OA patients group and control group, and in the knee OA patients group, the serum levels of leptin decreased significantly (P<0.001) and the serum levels of soluble leptin receptor increased significantly (P<0.001) compared with control group. Therefore, LEPR SNP A668G is associated with susceptibility to knee OA, which would be used as the genetic marker in predicting the risk of knee OA and would be one of the candidate genes in early prevention and control.