RESEARCH ARTICLE
An Association Study of Interleukin 18 Receptor Genes (IL18R1 and IL18RAP) in Lumbar Disc Degeneration
Ahmad Omair*, 1, Benedicte Alexandra Lie2, Olav Reikeras1, Jens Ivar Brox1
Article Information
Identifiers and Pagination:
Year: 2012Volume: 6
First Page: 164
Last Page: 171
Publisher ID: TOORTHJ-6-164
DOI: 10.2174/1874325001206010164
Article History:
Received Date: 23/1/2012Revision Received Date: 22/3/2012
Acceptance Date: 23/3/2012
Electronic publication date: 20/4/2012
Collection year: 2012

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Abstract
Objectives:
To examine association of candidate genetic variants in structural, inflammatory, matrix modifying, vitamin D receptor genes and variants associated with osteoarthritis, with surgical candidates and surgical patients with lumbar disc degeneration (LDD), in light of their previously reported susceptibility for LDD.
Methods:
Genotyping of 146 Norwegian LDD patients and 188 Norwegian controls was performed for 20 single-nucleotide polymorphisms (SNPs) from collagen, aggrecan, interleukin, VDR, MMP3 and COX2 genes and 7 SNPs from osteoarthritic genes.
Results:
The neighboring genes IL18R1 and IL18RAP polymorphisms (rs2287037 and rs1420100), showed a statistically non-significant risk for developing LDD (OR 1.36 [95 % CI 0.99 – 1.87]; p=0.06 and OR 1.33 [95 % CI 0.98-1.81]; p=0.07). Homozygosity of these risk alleles was associated with LDD (p=0.023 and p=0.027). The non-risk alleles at these SNPs were situated on a haplotype negatively associated with LDD (p=0.008). Carriage of at least one non-risk allele at both loci also reduces the risk of developing LDD (OR 0.51 [95 % CI 0.33-0.80]; p=0.003).
Conclusion:
Our findings support the polygenic nature of LDD and suggest that variation in interleukin 18 receptor genes could affect the risk of severe LDD and associated low back pain.