 If the fissures reach the periphery of the "annulus", the nuclear material can pass through as a disc herniation.Several genes have been implicated in intervertebral disc degeneration.Probable candidate genes include type I collagen (sp1 site), type IX collagen, vitamin D receptor, aggrecan, asporin, MMP3, interleukin-1, and interleukin-6 polymorphisms.