CHST6 and macular corneal dystrophy: Recessive CDs, such as macular corneal dystrophy (MCD), gelatinous drop-like corneal dystrophy (GDCD), and congenital hereditary endothelial dystrophy II (CHED II), are attractive targets for AAV-based gene therapy because the open-reading frames (ORF) of the three genes involved (CHST6, M1S1, and SLC4A11) range from 0.9 to 2.7 kb, the ideal size for an AAV-based gene complementation approach [52].