Macrophthalmia, Colobomatous, with Microcornea
Patient Information
Characteristics
Background and History
A large number of eye malformations involve the globe and the cornea. Many are quite rare and this disorder is one of them.
Clinical Correlations
The eyeball is larger than normal causing nearsightedness. The cornea (windshield of the eye) is smaller and flatter than normal and often the iris lacks a round pupil (keyhole pupil) with a defect extending into the eyeball that may extend to the optic nerve in the back. Depending on the degree of involvement of the nerve, vision may vary widely. Some patients also have glaucoma. No abnormalities elsewhere in the body have been reported.
Genetics
Inheritance
This disorder is inherited in a vertical pattern as it is passed from one generation to the next in what is called an autosomal dominant pattern of inheritance. The risk of this disorder among offspring to affected individuals is 50 per cent. No specific gene mutation has been identified.
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
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