Degeneration scores were significantly worse in cases with COL1A1 Sp1, COL9a3 Trp3, and VDR TaqI mutations; however, COL9a2 Trp2 mutation was not associated with a difference in the severity of disc degeneration.
Genetic studies have demonstrated that a polymorphism (Trp2 allele) in COL9A2 coding for alpha2 chain of collagen IX predisposes the individual to disc degeneration.