Article

The IC3D classification of the corneal dystrophies

Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA.
Cornea (Impact Factor: 2.36). 01/2009; 27 Suppl 2(Suppl 2):S1-83. DOI: 10.1097/ICO.0b013e31817780fb
Source: PubMed

ABSTRACT The recent availability of genetic analyses has demonstrated the shortcomings of the current phenotypic method of corneal dystrophy classification. Abnormalities in different genes can cause a single phenotype, whereas different defects in a single gene can cause different phenotypes. Some disorders termed corneal dystrophies do not appear to have a genetic basis.
The purpose of this study was to develop a new classification system for corneal dystrophies, integrating up-to-date information on phenotypic description, pathologic examination, and genetic analysis.
The International Committee for Classification of Corneal Dystrophies (IC3D) was created to devise a current and accurate nomenclature.
This anatomic classification continues to organize dystrophies according to the level chiefly affected. Each dystrophy has a template summarizing genetic, clinical, and pathologic information. A category number from 1 through 4 is assigned, reflecting the level of evidence supporting the existence of a given dystrophy. The most defined dystrophies belong to category 1 (a well-defined corneal dystrophy in which a gene has been mapped and identified and specific mutations are known) and the least defined belong to category 4 (a suspected dystrophy where the clinical and genetic evidence is not yet convincing). The nomenclature may be updated over time as new information regarding the dystrophies becomes available.
The IC3D Classification of Corneal Dystrophies is a new classification system that incorporates many aspects of the traditional definitions of corneal dystrophies with new genetic, clinical, and pathologic information. Standardized templates provide key information that includes a level of evidence for there being a corneal dystrophy. The system is user-friendly and upgradeable and can be retrieved on the website www.corneasociety.org/ic3d.

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    • "In this study, we describe histopathological findings and a novel mutation in the CHST6 gene (p.Arg205Trp [c.613C>T]) in a case of MCD [7]. Light microscopy revealed abnormal deposits of glycosaminoglycans in Bowman's histiocytes and keratocytes, as well as between the stromal lamellae, Descemet's membrane, and endothelium. "
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    Korean Journal of Ophthalmology 12/2013; 27(6):454-8. DOI:10.3341/kjo.2013.27.6.454
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    • "The combined features of lattice and granular dystrophies in the same cornea resulting from mutations in the same gene raises the questions of validity of relying solely on clinical and histological evidence to classify disease. Modern genotyping now enables greater accuracy in the nosology and the International Committee for Classification of Corneal Dystrophies (IC3D) has already incorporated this information into their recent reclassification of these dystrophies [3]. Initial clinical symptoms of the heterozygous form of ACD appear during the first or second decade of life. "
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    • "The diagnosis of FECD was based on clinical signs on the slit lamp examination (occurrence of endothelial guttae, corneal edema) and in all the cases was confirmed by the presence of characteristic lesions and polymegathism and pleomorphism of the endothelial cells on in vivo confocal microscopy (IVCM) examination [19, 20]. The control subjects had no clinical evidence of FECD and presented healthy corneal endothelium on IVCM. "
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