Overview of Possible Roles of OPLL-Associated Genes in OPLL Development
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In addition to classical genomic studies, a genome-wide association study for ossification of the posterior longitudinal ligament (OPLL) was performed and susceptibility loci and candidate genes were identified. Among them, R-spondin 2 (RSPO2) has been focused on as a potent candidate. RSPO2 is a member of the R-spondin secreted protein family and enhances canonical Wnt signaling activity. A recent study showed that RSPO2 suppresses the early-stage differentiation of chondrocytes and that its expression is significantly lower in fibroblasts carrying the risk allele. These findings suggest that RSPO2 may suppress the differentiation of mesenchymal stem cells toward chondrocytes via the inhibition of canonical Wnt signaling. To obtain a deeper understanding of the pathophysiology of OPLL, appropriate experimental animal models and expression analyses of candidate genes in surgical specimens from OPLL patients are necessary.
KeywordsOssification of the posterior longitudinal ligament (OPLL) Genome-wide association study (GWAS) Susceptibility gene
I thank Edanz (www.edanzediting.co.jp) for editing the English text of the draft of this manuscript.
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