In the TGFB1 (TGFβ1) gene, the CC genotype of the 869T>C polymorphism was found to be associated with an increased risk of radiological OPLL development in one study (OR 4.5, p = 0.0004) [45], but it had no such association in a recent study that involved almost double the number of cases (p = 0.656) [46]. The gene discussed is TGFB1; the disease is ossification of the posterior longitudinal ligament of the spine.