Association of bone morphogenetic protein-2 gene polymorphisms with susceptibility to ossification of the posterior longitudinal ligament of the cervical spine in Chinese patients

Abstract

Objective To investigate the association of single nucleotide polymorphism (SNPs) of bone morphogenetic protein-2 (BMP-2) gene encoding region with susceptibility to ossification of the posterior longitudinal ligament (OPLL) of cervical spine and its severity in Chinese patients.Methods A total of 420 OPLL patients and 506 age-and sex-matched controls were studied.Genomic DNA was isolated from venous blood and polymerase chain reaction (PCR) was performed with a standerd protocol.The PCR products were analyzed by direct sequencing.To compare the genotypic and allelic distribution between OPLL cases and control subjects.Results The number of subjects in the total study population with the Ser37Ala (T/G)TT,TG and GG genotypes was 752,174 and 0,respectively,with frequencies of 81％,19％ and 0,respectively.There was a statistical difference between OPLL cases and control subjects (P ＜ 0.001),The TG genotype was associated with the occurrence of OPLL.The number of subjects in the total study population with the Arg190Ser (A/T) AA,AT and TT genotypes was 228,464 and 234,respectively,with frequencies of 24％,50％ and 26％,respectively.There was a statistical difference between OPLL cases and control subjects (P ＜ 0.01),The AT genotype was associated with the occurrence of OPLL.For the Ser87Ser (A/G) polymorphism,patients with G allele had a significantly greater number of ossified vertebrae compared with patients without A allele.Condusion The Ser37Ala (T/G) polymorphism in exon2 and the Arg190Ser (A/T) polymorphism in exon3 of BMP-2 gene are associated with the occurrence of OPLL.The Ser87Ser (A/G) polymorphism in exon2 of BMP-2 gene is associated with more extensive OPLL.BMP-2 gene is the susceptibility gene of OPLL. Key words: Ossification of posterior longitudinal ligament; Bone morphogenetic protein-2; Single nucleotide polymorphisms