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The official name of this gene is “keratin 3, type II.”
KRT3 is the gene's official symbol. The KRT3 gene is also known by other names, listed below.
The KRT3 gene provides instructions for making a protein called keratin 3. Keratins are a group of tough, fibrous proteins that form the structural framework of epithelial cells, which are cells that line the surfaces and cavities of the body. Keratin 3 is produced in a tissue on the surface of the eye called the corneal epithelium. This tissue forms the outermost layer of the cornea, which is the clear front covering of the eye. The corneal epithelium acts as a barrier to help prevent foreign materials, such as dust and bacteria, from entering the eye.
The keratin 3 protein partners with another keratin protein, keratin 12, to form molecules known as intermediate filaments. These filaments assemble into strong networks that provide strength and resilience to the corneal epithelium.
The KRT3 gene belongs to a family of genes called KRT (keratins).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
At least three mutations in the KRT3 gene have been found to cause Meesmann corneal dystrophy, an eye disease characterized by the formation of tiny cysts in the corneal epithelium.
All of the identified KRT3 gene mutations associated with Meesmann corneal dystrophy change single protein building blocks (amino acids) in the keratin 3 protein. These changes occur in a region of the protein that is critical for the formation and stability of intermediate filaments. The altered keratin 3 protein interferes with the assembly of intermediate filaments, weakening the structural framework of the corneal epithelium. As a result, this outer layer of the cornea is abnormally fragile and develops the cysts that characterize Meesmann corneal dystrophy. The cysts likely contain clumps of abnormal keratin proteins and other cellular debris. When the cysts break open (rupture), they cause eye irritation, increased sensitivity to light (photophobia), and related symptoms.
Cytogenetic Location: 12q13.13
Molecular Location on chromosome 12: base pairs 52,789,684 to 52,805,716
The KRT3 gene is located on the long (q) arm of chromosome 12 at position 13.13.
More precisely, the KRT3 gene is located from base pair 52,789,684 to base pair 52,805,716 on chromosome 12.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about KRT3 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
acids ; bacteria ; cornea ; cysts ; cytokeratin ; epithelial ; epithelium ; gene ; intermediate filaments ; keratin ; motif ; photophobia ; protein ; resilience ; rupture ; sensitivity ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.