[Genetic study on OPLL in the cervical spine with HLA haplotype]

HLA typing was carried out in 27 families with cases of ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, with haplotype analysis for genetic factors. The results showed a significantly higher incidence of rare haplotypes in probands than in the general Japanese population, suggesting that certain genes linked to HLA are responsible for OPLL. On examination of the distribution of HLA haplotypes in families with members suffering from cervical OPLL, no evidence of OPLL was found in members with only one haplotype in common with the proband. In 9 of 15 siblings with two haplotypes in common, however, OPLL was observed. Further analysis of HLA haplotyping may contribute to the elucidation of the genetic determinants of OPLL linked to two HLA haplotypes, probably based on multifactorial inheritance.