Variants of acan gene associate with severity of lumbar disc degeneration

Abstract

INTRODUCTION AND OBJECTIVES: Structural integrity of aggrecan (coded by ACAN gene) plays a major role in lumbar disc degeneration (LDD). Single nucleotide polymorphisms (SNPs) of ACAN gene have been implicated in LDD. The study aimed to determine the associations between SNPs of ACAN gene and the severity of disc space narrowing (DSN) and osteophytes (OS) of lumbar spine in patients with chronic mechanical low back pain (CMLBP). METHOD: A descriptive cross-sectional study was carried out on 120 patients with CMLBP. Lateral lumbar X-rays were assessed for severity of DSN and OS using a semiquantitative scores (grade 0-3). Twenty-seven exonic SNPs of the ACAN gene were genotyped on a Sequenom mass array iPLEX platform. Multiple linear regression analysis was carried out adjusting for age and body mass index. RESULTS: Mean age was 51.46 ± 10.43 years. 82 (68.3%) were females. 30 (25%) were obese. 31 (25.8%) and 47 (39.2%) had grade 1 DSN and AOS respectively, while 42 (35%) and 13 (10.8%) had grade ≥ 2 DSN and AOS, respectively. “A” allele of rs2882676 (regression coefficient (β) = -0.25, p<0.03), “A” allele of rs1042630 (β = -0.28, p<0.01) and “T” allele of rs1042631 (β = -0.28, p<0.02) were negatively associated with the severity of DSN. “T” allele of rs16942341 (β = 0.4, p<0.02) and “G” allele of rs28407189 (β = 0.4, p<0.02) were positively associated with the severity of AOS. CONCLUSION: SNPs of ACAN gene are associated with severity of degenerative changes of the lumbar spine.