Genetic study on ossification of posterior longitudinal ligament.

Family studies and blood grouping tests were conducted in an attempt to elucidate the etiology and genetic mechanism of ossification of posterior longitudinal ligament of the spine (OPLL). Analysis of the collected date revealed the following results: Testing of inheritance pattern Fitness of OPLL to the hypotheses of simple recessive inheritance, simple dominant inheritance and multifactorial inheritance was tested, but fitness to any one of these hypotheses was statistically denied. Analyses of OPLL and genetic markers A comparative study was made between the OPLL patients and healthy donors residing in Tokyo on the phenotype frequency of the blood groups (eight systems), serum groups (six systems) and red cell enzyme groups (three systems). A significant association of OPLL with MN blood groups, Hp types and PGM1 types was observed. Examination of the correlation after combining MN and Hp showed the coefficient of contingency to be C = 0.6739 and that after the multiple combination of MN, Hp and PGM1 revealed the coefficient of contingency to be C = 0.8923, indicating a remarkably high correlation.