Congenital hereditary endothelial dystrophy II (CHED II) is a rare subtype of posterior corneal dystrophy (see this term) characterized by a diffuse ground-glass appearance of the corneas and marked corneal thickening from birth with nystagmus, and blurred vision.
Prevalence of this form of corneal dystrophy is unknown. Most cases have been identified in children of consanguineous parents from Saudi Arabia, India, Pakistan, Myanmar (Burma) and Ireland.
Diffuse ground glass lesions are present from birth and are accompanied by nystagmus. Tearing and photophobia are minimal or absent. The course is relatively stable. Patients also occasionally have sensorineural deafness. The cornea is swollen due to extensive stromal edema.
Most cases are caused by homozygous mutations in the SLC4A11 gene. A high degree of mutational heterogeneity has been detected and genetic heterogeneity may exist as no mutations in SLC4A11 or in its promoter region have been detected in some affected families. In CHED II, an increased tendency for the abnormal endothelium to synthesize a homogenous, posterior, non-banded Descemet membrane is observed.
Transmission appears to be autosomal recessive.
Patients with CHED II usually require a penetrating keratoplasty. Procedures for repairing the posterior surface of the cornea, such as a deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), or Descemet stripping automated endothelial keratoplasty (DSAEK) are technically difficult in young children.
Last update: May 2012