Mutations in the carbohydrate sulfotransferase (CHST6, OMIM 605294) gene on chromosome 16q22 encoding corneal glucosamine N-acetyl-6-sulfotransferase (C-GlcNAc6ST), an enzyme that transfers sulfate to the unsulfated keratan chains, have been identified as the cause of MCD in humans [6]. This evidence concerns the gene CHST6 and macular corneal dystrophy.