Corneal Dystrophy, Congenital Endothelial 1
Patient Information
Characteristics
Background and History
This congenital disorder of the cornea (windshield) of the eye was first described in 1960. It is only one of many causes of cloudy corneas but this one usually has its onset in early childhood.
Clinical Correlations
The cornea may be cloudy at birth and at that time may be confused with congenital glaucoma or another form of congenital corneal clouding (Harboyan syndrome). The latter, however, is associated with hearing loss which may not be evident at birth. The swelling of the cornea, which results in the clouding, may be progressive. Vision is, of course, impacted but near normal vision is the rule in young children while older persons may experience blurred vision as the corneal cloudiness progresses. Light sensitivity and tearing are common symptoms. The disorder is caused by a genetic defect that leads to damage in the posterior layer of the cornea, called the endothelium. This single layer of cells is importance in the maintenance of normal hydration of the cornea and, when damaged, allows the cornea to swell with fluid.
Congenital glaucoma is sometimes present as well.
Genetics
Inheritance
This is an autosomal dominant disorder resulting from a gene mutation on chromosome 20. An affected parent can expect that each child has a 50% risk of inheriting the disease.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission
Diagnosis and Prognosis
Only an ophthalmologist can diagnose this disorder although simple inspection of the eye can discern the clouding of the cornea. Other conditions such as glaucoma must be ruled out and only a gene test can confirm the diagnosis. Glaucoma, if present, must be treated vigorously. The visual prognosis is good. In severe cases a corneal graft may be necessary to restore good vision. The surgical success rate is high.
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