Table 1.

Additional genetic factors that may be involved in the pathogenesis of IDD.

Gene name	References	Population	Comments
MMP-2	Dong et al., 200760	162 young Chinese individuals (25.4 ± 3.5 years of age)	3-fold higher risk for lumbar disc disease in individuals with the MMP-2-1306CC genotype compared with individuals with at least 1 variant T allele
MMP-9	Sun et al., 200961	408 individuals with IDD from north China	A 2-fold increased risk of IDD found in individuals with CT/TT genotype compared with individuals with CC genotype
IGF-1R	Urano et al., 200859	434 postmenopausal Japanese women	The G allele (GG and GC) of the IGF-1R gene was overrepresented in the population showing more severe disc space narrowing on radiographs
CILP	Seki et al., 200562	467 Japanese men and women	CILP plays a role in lumbar disc degeneration by regulating TGF-beta signaling pathway
TIMP1 COX2 THSD2	Valdes et al., 200552	700 English women	Polymorphisms of TIMP1, COX2 and THSD2 were associated with progression of IDD