MedGen

Posterior polymorphous corneal dystrophy (PPCD) is a rare disorder involving metaplasia and overgrowth of corneal endothelial cells (Krafchak et al., 2005). In patients with PPCD, these cells manifest in an epithelial morphology and gene expression pattern, produce an aberrant basement membrane, and, sometimes, spread over the iris and nearby structures in a way that increases the risk for glaucoma. Symptoms can range from very aggressive to asymptomatic and nonprogressive, even within the same family. The age of diagnosis is, most often, in the second or third decade of life. Clinically, PPCD is characterized by vesicles, bands, and polymorphous opacities at the level of the Descemet membrane and corneal endothelium. Peripheral anterior iris adhesions, iris atrophy, pupillary ectropion, and corectopia may also develop. Occasional severe visual disability results from secondary glaucoma or corneal edema. On ultrastructural examination, corneal endothelial cells show fibroblastic and epithelial-like transformation (summary by Liskova et al., 2012). Genetic Heterogeneity of Posterior Polymorphous Corneal Dystrophy Other forms of PPCD include PPCD2 (609140), caused by mutation in the COL8A2 gene (120252) on chromosome 1p34.3; PPCD3 (609141), caused by mutation in the ZEB1 gene (189909) on chromosome 10p; and PPCD4 (618031), caused by mutation in the GRHL2 gene (608576) on chromosome 8q22. [from OMIM]

The term corneal dystrophy embraces a heterogenous group of bilateral genetically determined non-inflammatory corneal diseases that are restricted to the cornea. [from HPO]

Transmission of gene defects or chromosomal aberrations/abnormalities which are expressed in extreme variation in the structure or function of the eye. These may be evident at birth, but may be manifested later with progression of the disorder. [from MeSH]

A non-neoplastic or neoplastic disorder that affects the cornea. Representative examples include keratitis, bullous keratopathy, and squamous cell carcinoma. [from NCI]

A posterior polymorphous corneal dystrophy that has material basis in autosomal dominant inheritance of mutation in the OVOL2 gene on chromosome 20p11.23. [from MONDO]

The presence of central, fine, whitish granular lesions in the stroma of the cornea. This type of corneal dystrophy is usually asymptomatic and begins in childhood and shows a slow progression. Later in the course, the corneal epithelium and Bowman's layer may be affected. Histologically, the cornea shows a uniform deposition of hyaline material. [from HPO]

A closed sac, having a distinct membrane and division compared to the nearby tissue located within the anterior chamber. The sac that may contain air, fluids, or semi-solid material. [from HPO]

Groenouw type I, or granular type I, corneal dystrophy (CDGG1) is an autosomal dominant disorder characterized by irregular aggregates of hyaline material in the corneal stroma. These aggregates can cause significant visual disturbance and may require corneal transplantation for restoration of visual acuity or for relief from recurrent corneal erosions (summary by Stone et al., 1994). [from OMIM]

Posterior polymorphous corneal dystrophy-3 (PPCD3) is a rare disorder involving metaplasia and overgrowth of corneal endothelial cells (Krafchak et al., 2005). In patients with PPCD, these cells manifest in an epithelial morphology and gene expression pattern, produce an aberrant basement membrane, and sometimes spread over the iris and nearby structures in a way that increases the risk for glaucoma. Symptoms range from very aggressive to asymptomatic and nonprogressive, even within the same family. The age of diagnosis is most often in the second or third decade of life. PPCD3 is often associated with corneal steepening, and some patients may be diagnosed with keratoconus before PPCD (Fernandez-Gutierrez et al., 2023). Retrocorneal membranes have been reported, sometimes extending onto the lens (Moroi et al., 2003). For a discussion of genetic heterogeneity of posterior polymorphous corneal dystrophy, see PPCD1 (122000). [from OMIM]

A benign or malignant neoplasm that affects the cornea. [from NCI]