Association Between Human Aggrecan Gene Polymorphism And Lumbar Degenerative Disc Disease

Background:Variable number of tandem repeat (VNTR) polymorphism has been identified in human aggrecan gene, which refers to different repeats in VNTR and thus different fragment length.Objective:To describe the distribution characteristics of the VNTR polymorphism in southern Chinese Han people and investigate the association between VNTR polymorphism and lumbar degenerative disc disease (LDDD).Methods:Participants aged between20-40years old were chose from southern Chinese Han people, and disease group and control group with50cases respectively were selected depending on MRI result of LDDD. Lumbar magnetic resonance imaging (MRI) of each participant was evaluated. Moreover, genomic deoxyribonucleic acid (DNA) was extracted from peripheral blood of all participants and polymerase chain reaction (PCR) was performed to detect the alleles of the aggrecan gene. x2test was used to analyze the distribution of the VNTR polymorphism between disease group and control group, then Spearman rank correlation model was performed to explore the association between VNTR polymorphism and intervertebral disc degeneration grade, degeneration level, herniation type and herniation level.Results:The genotyping identified12alleles ranging from21to32repeats, among which allele27(26.5%) was the most common form. The alleles ranging from21to26were significantly overrepresented in the disease group (x2=3.922, P=0.048). Through Spearman rank correlation model, different VNTR alleles were found significantly correlated with grade of disc degeneration and multilevel disc degeneration (P is0.017and0.040respectively), but no obvious association was found between VNTR alleles and the types and levels of lumbar disc herniation (P is0.050and0.056respectively). Moreover, numbers of carrying short alleles (A21-A26) were statistically correlated with grade of disc degeneration, multilevel disc degeneration and multilevel disc herniation (P is0.026,0.029and0.037respectively), but without the herniation type as well (P=0.089).Conclusion:Aggrecan gene in southern Chinese Han people involved in this research shows VNTR polymorphism. Carrying a copy of short alleles might increase the risk of severe degeneration, multilevel degeneration and multilevel herniation, and thus the possibility of LDDD.