Corneal Dystrophy, Gelatinous Drop-like
Patient Information
Characteristics
Background and History
The cornea is the clear windshield at the front of the eye. A number of gene mutations are responsible for disease in this tissue which often causes loss of the normal transparency and results in blurred vision. This type also causes irregularity in the surface which leads to painful irritation.
Clinical Correlations
Gelatinous drop-like corneal dystrophy results from grayish deposits of abnormal material near the surface of the cornea. This creates an irregular surface, sometimes described as resembling a mulberry. Periodic symptoms consisting of painful scratchy sensations and sensitivity to light may appear in the first decade of life . The abnormal deposits can enlarge and when they are dense enough vision can be seriously impaired. Cataracts have been reported to occur in young people with this disorder. There are no systemic abnormalities associated with the corneal disease.
Genetics
Inheritance
This is an autosomal recessive disorder which requires two mutations of the same gene, one contributed by each normal, carrier parent. Such parents can expect that each of their children have a 25% risk of inheriting the disease. The family pattern is a horizontal one since the disease is not passed directly from parent to child.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
This disorder can only be diagnosed by an ophthalmologist by examination of the eye. The prognosis is generally good although the disease may progress to cause significant loss of vision. A corneal transplant can successfully restore clear vision but the deposits tend to recur after a few years.
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