Fig. 3From: Genetic polymorphisms in bone morphogenetic protein receptor type IA gene predisposes individuals to ossification of the posterior longitudinal ligament of the cervical spine via the smad signaling pathwayThe distribution of ossified cervical vertebrae of OPLL patients in each subgroup classified by C allele type in 4A > C polymorphism of BMPR-IA gene. The number of ossified vertebrae is shown under each bar. Data is expressed as means (bars) ± SD (error bars). The difference in the number of ossified vertebrae between the non-carriers and carriers of C allele type was statistically significant. ** P < 0.001Back to article page