OBJECTIVECOL9A1 gene is located in the susceptibility region of idiopathic congenital talipes equinovarus (ICTEV) (6q12-13). This study aimed to investigate the expression of the COL9A1 gene and the distribution of single nucleotide polymorphism (SNP) of COL9A1 gene in patients with ICTEV and normal controls.

METHODSImmunohistochemistry was used to detect the expression of COL9A1 in 25 children with ICTEV and 5 normal controls. The frequencies of genotypes and allele of two SNPs in COL9A1 gene rs35470562 and rs1135056 were investigated by PCR-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing in 118 patients with ICTEV and 100 normal controls.

RESULTSThe COL9A1 protein expression was significantly higher in 22 (88%) out of 25 children with ICTEV than normal controls. There were significant differences in the frequencies of genotypes and allele of rs1135056 in COL9A1 gene between the ICTEV and the control groups: the G allele frequency was higher, the frequency of AA genotype was lower, and the frequencies of AG and GG genotypes were higher in ICTEV patients than those in healthy controls (P<0.05).

CONCLUSIONSCOL9A1 protein is highly expressed in patients with ICTEV and rs1135056, which is located in the coding region of COL9A1 gene, may be associated with the pathogenesis of ICTEV.