“…More than half of the genes were reported in one type of study or in single studies. A few genes, encoded chains of collagens ( COL5A1, COL4A3 , and COL4A4 ) ( 57 , 59 , 61 , 67 , 72 , 76 , 78 , 84 , 87 , 88 , 90 ), collagen cross-linking enzyme ( LOX ) ( 18 , 30 , 90 ), factor for the synthesis or organization of collagen fibers ( ZNF469 ) ( 27 , 32 , 34 , 46 , 47 , 62 , 65 ), and others ( MIR184 and VSX1 ) ( 6 , 7 , 16 , 19 , 24 , 40 , 56 , 82 , 85 ) were identified in different types of studies, such as pathogenic mutation analysis, polymorphism association analysis, and family-based linkage analysis. However, the occurrence rate of these gene mutations in the population was relatively low, and in many populations, it could not even be verified ( 25 , 195 – 202 ), which suggested that KC is genetically heterogeneous.…”