Similarly, mutations in the collagen-α chain genes, COL2A1, COL9A2, COL11A1, and COL11A2, have been associated with different forms of Stickler syndrome (OMIM#108300, #614284, #604841, and #184840, respectively), a clinically variable condition that includes cleft palate. Here, COL2A1 is linked to Stickler syndrome.