COL9A2 and Kniest dysplasia: Interestingly, the phenotype of OSD-affected NID in the present study is actually more similar to other human ophthalmoarthropathies, including Kniest dysplasia (caused by mutations in COL2A1) [21, 22], Marshal syndrome (caused by mutations in COL11A1) [15, 23, 26] and finally STL types I, II, IV and V (caused by mutations in COL2A1, COLL11A1, COL9A1 and COL9A2 respectively) [12, 13, 15–20].