Genetics
An inheritable gene variation may cause increased susceptibility. People with a variation in a gene that encodes the cartilage intermediate-layer protein (CILP) were 1.6 times more likely to have the disease than persons without the variation. CILP is a normal component of disc tissue. The gene variation causes a version of CILP that disrupts normal building and maintenance of cartilage.
Under normal circumstances, CILP slows the activity of another protein, TGFβ1. TGFβ1 regenerates the cartilage matrix tissue. The variant CILP inhibits TGFβ1 to an abnormal degree, allowing for degeneration of the disc matrix. (Seki, et al., 2005)
Read more about this topic: Lumbar Disc Disease