Although the pathogenesis of LDD is multivariate, genetic factors have been reported to play an important role in LDD, including collagen I alpha 1 (COL1A1) gene, collagen IX alpha 1 chain (COL9A1) gene, collagen IX alpha 2 chain (COL9A2) gene, collagen IX alpha 3 chain (COL9A3) gene, vitamin D receptor gene, and cartilage intermediate-layer protein gene [4–7]. The gene discussed is COL9A3; the disease is Lhermitte-Duclos disease.