Test Directory

Clinical significance

According to the recent classification by the International Committee for Classification of Corneal Dystrophies (IC3D), Category 1 refers to corneal dystrophies in which the causative genes and mutations are identified.

Category 1 corneal dystrophies are autosomal dominant genetic disorders caused by mutations in the transforming growth factor, beta-induced (TGFBI) gene located at 5q31. In addition to the well-known Avellino corneal dystrophy, there are five distinct characteristics for other types, including lattice, granular, Thiel-Behnke, and Reis-Bucklers dystrophies:

1) Avellino Corneal Dystrophy:

This is the most common corneal dystrophy in Koreans, characterized by central corneal opacities in both eyes. It is caused by the R124H mutation in the TGFBI gene. The estimated occurrence in Korea is about 1 in 870 individuals. Depending on the genetic mutation, a sudden decrease in vision occurs around the age of 3 or 12.

2) Lattice Corneal Dystrophy:

This disorder is characterized by thin linear lattice-like opacities in the cornea, primarily caused by the R124C mutation in the TGFBI gene.

3) Reis-Bucklers Corneal Dystrophy:

It manifests with honeycomb-shaped corneal opacities and is mainly caused by the R124L mutation in the TGFBI gene.

4) Granular Corneal Dystrophy:

This disorder exhibits irregular grid-like corneal opacities and is caused by the R555W mutation in the TGFBI gene.

5) Thiel-Behnke Corneal Dystrophy:

A variant type of Reis-Bucklers Corneal Dystrophy, it is characterized by recurrent corneal erosion. This form is primarily caused by the R555Q mutation in the TGFBI gene.

**It is crucial to diagnose individuals with these corneal dystrophies before undergoing laser eye surgery (such as LASIK, LASEK, or PRK) for vision correction, as the procedure can lead to rapid progression of corneal opacity and vision loss due to various stimulating factors.

Specimen Collection Instruction

Send three paraffin blocks, three unstained coating slides (thickness: 3-4 μm), and one H&E slide along with the pathology report, test request form, and genetic test consent form.

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