OMIM ID:
Corneal Dystrophy, Posterior Polymorphous 4
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
The posterior corneal surface becomes highly irregular as the endothelial cells become variable in size and in number. There may be focal areas of multilayering of endothelial cells. Most patients have a significant reduction in endothelial cell density which eventually leads to corneal edema and blurred vision. Some patients have anterior synechiae and corectopia with secondary glaucoma.
Corneal edema has been noted in infants at several months of age. Painful bullous keratopathy or uncontrollable glaucoma may lead to enucleation in adult life.
Systemic Features
The posterior corneal surface becomes highly irregular as the endothelial cells become highly irregular in size and in number. There may be focal areas of multilayering of endothelial cells. Most patients have a significant reduction in endothelial cell density which eventually leads to corneal edema and blurred vision. Some patients have anterior synechiae and corectopia with secondary glaucoma.
Corneal edema has been noted in infants at several months of age. Painful bullous keratopathy or uncontrollable glaucoma may lead to enucleation in adult life.
Genetics
Inheritance
Heterozygous mutations in the GRHL2 gene (8q22.3-q24.12) are responsible for this condition.
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