Congenital Hereditary Endothelial Dystrophy Type I

A rare subtype of posterior corneal dystrophy characterized by a diffuse ground-glass appearance of the corneas and marked corneal thickening from birth or infancy without nystagmus, with blurred vision.

Epidemiology

Prevalence of this form of corneal dystrophy is unknown.

Clinical description

Lesions become manifest in the first two years of life with photophobia and tearing. CHED I progresses slowly over 5 to 10 years with increasingly blurred vision, which is worse in the morning. The cornea is swollen due to extensive stromal edema.

Etiology

Exact etiology is unknown but the gene responsible for CHED I has been mapped to the pericentromeric region of chromosome 20 (20p11.2q11.2) in an area overlapping a gene for a type of posterior polymorphous corneal dystrophy (PPCD; see this term).

Diagnostic methods

A posterior collagenous layer of fibrillary collagen contributing to thickening of Descemet membrane is found. Endothelial cells are scant or degenerated when present.

Differential diagnosis

The condition should be distinguished from PPCD due to similar clinical features.

Genetic counseling

Transmission appears to be autosomal dominant.

Management and treatment

Patients with CHED I usually require a penetrating keratoplasty, because 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) and technically difficult in young children.