Association between polymorphism of the transforming growth factor-β1 gene with the radiologic characteristic and ossification of the posterior longitudinal ligament

Study Design: A study was conducted to examine the relation between the transforming growth factor-beta1 (TGF-beta1) polymorphism (T-->C transition in the signal sequence) and ossification of the posterior longitudinal ligament (OPLL). Objective. To investigate the association between the polymorphism of TGF-beta1 and the radiologic characteristics of OPLL. Summary of Background Data. Ossification of the posterior longitudinal ligament has a strong genetic background. Several genes contribute to the expression of OPLL. Transforming growth factor-beta1 is present in the ossified matrix and chondrocytes of cartilage adjacent to areas of OPLL. Methods. The difference in the TGF-Tbeta1 allele distribution ("TT," "TC," and "CC") between 369 patients with OPLL and 258 control subjects was assessed. The relations between the allele frequency and radiologic features of OPLL involving the cervical, thoracic, and lumbar spine and the width of the ossification area were evaluated. Results. There was no statistical difference with respect to the type of OPLL and the width of the ossification area for the TGF-Tbeta1 allele between the OPLL and the control groups. However, in the patients with "TC" or "CC" alleles, OPLL frequently was found in the cervical, thoracic, and/or lumbar spine. Conclusions. Transforming growth factor-beta1 polymorphism is not a factor associated with the occurrence of OPLL, but rather a factor related to the area of the ossified lesion. The "C" allele might be a risk factor for patients with OPLL in other areas in addition to the cervical lesion.