Congenital hereditary endothelial dystrophy (CHED) is a rare inheritable disorder of the corneal endothelium characterized by bilateral symmetric corneal clouding (edema) with varied severity from mild opacification to milky, ground-glass opacification without other anterior segment abnormalities, usually evident at birth or in the early years of life. Two subtypes of CHED based on differences in the mode of inheritance are known, an autosomal dominant (CHED1) and an autosomal recessive (CHED2) type. Clinically, both forms of the disorder are similar; the distinction between them is made by the age at onset and the presence or absence of associated symptoms. Both CHED1 and CHED2 have been mapped to chromosome 20. The Solute Carrier family 4 (sodium borate cotransporter) member 11 (SLC4A11) has been identified as the candidate gene for CHED2. Mutations in SLC4A11 are described in Harboyan syndrome, which is characterized as CHED2 with hearing loss. Most patients with CHED have severe visual impairment and often require penetrating keratoplasty.
