Several SNPs in BMP2 (rs3178250, rs2273073, rs235768, rs1049007) or SNPs located upstream or downstream of BMP2 (rs1116867, rs965291) are reported to be significantly associated with the occurrence or the severity of OPLL in several candidate gene association studies involving Chinese patients and control subjects [67–70]. The gene discussed is BMP2; the disease is ossification of the posterior longitudinal ligament of the spine.