GSN and corneal dystrophy: Genetic studies have identified eleven chromosomes related to corneal dystrophy: 1, 2, 5, 9, 10, 12, 13, 16, 17, 20, and X. Several genes in regions responsible for corneal dystrophy have also been identified, including the transforming growth factor-beta-induced gene (TGFBI), the carbohydrate sulfotransferase 6 gene (CHST6), the gelsolin gene (GSN), the keratin 3 gene (KRT3), the keratin 12 gene (KRT12) and the surface marker 1 gene (M1S1) [1,3].