Abstract: ObjectiveTo explore the relationship of single nucleotide polymorphism (SNPs) of the bone morphogenetic protein-4 (BMP-4) gene with the morbidity and severity of the ossification of posterior longitudinal ligament (OPLL) of the spine in Chinese patients. MethodsThe venous blood samples of 200 OPLL patients and 200 non-OPLL controls were measured with the DNA sequences in four locus of BMP-4 gene with polymerase chain reaction(PCR). ResultsThere was a significant association between the rs17563，rs2855532 polymorphism and the occurrence of OPLL （P＜0.05）. The ''T'' allele in these 2 SNPs promotes the extent of OPLL (P<0.05). However, no significant association in morbidity and severity was found between the other 2 SNPs (rs1957860, rs2071047). ConclusionSNPs in rs17563，rs2855532 associates with the morbidity and severity of the ossification of posterior longitudinal ligament of the spine in Chinese patients.

Key words: ossification of posterior longitudinal ligament, bone morphogenetic protein-4, gene, single nucleotide polymorphism