CHST6 and macular corneal dystrophy: Akama [10] and others [11-16] have described missense mutations, nonsense mutations, and insertions within the coding region in CHST6 in patients with type I macular corneal dystrophy (differentiation between types I and IA was not performed) whereas MCD type II is associated with deletions and rearrangements in the upstream region of CHST6 as well as missense mutations [10,16-19].