Reviewed April 2007
What is the official name of the KRT5 gene?
The official name of this gene is “keratin 5 (epidermolysis bullosa simplex, Dowling-Meara/Kobner/Weber-Cockayne types).”
KRT5 is the gene's official symbol. The KRT5 gene is also known by other names, listed below.
What is the normal function of the KRT5 gene?
The KRT5 gene provides instructions for making a protein called keratin 5. Keratins are a group of tough, fibrous proteins that form the structural framework of certain cells, particularly cells that make up the skin, hair, and nails. Keratin 5 is specifically produced in cells called keratinocytes in the outer layer of the skin (the epidermis).
Keratin 5 partners with a similar protein, keratin 14, to form molecules called keratin intermediate filaments. These filaments assemble into strong networks that help attach keratinocytes together and anchor the epidermis to underlying layers of skin. The network of keratin intermediate filaments provides strength and resiliency to the skin and protects it from being damaged by friction and other everyday physical stresses.
Researchers believe that keratin 5 may also play a role in transporting melanosomes, which are cellular structures that produce a pigment called melanin. The transport of these structures into keratinocytes is important for normal skin coloration (pigmentation).
Does the KRT5 gene share characteristics with other genes?
The KRT5 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? in the Handbook.
How are changes in the KRT5 gene related to health conditions?
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epidermolysis bullosa simplex - caused by mutations in the KRT5 gene
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More than 60 mutations in the KRT5 gene have been identified in people with epidermolysis bullosa simplex. Most of these genetic changes alter single protein building blocks (amino acids) used to make keratin 5. The most severe form of epidermolysis bullosa simplex, the Dowling-Meara type, usually results from mutations in regions of the KRT5 gene that are essential for the normal assembly of keratin intermediate filaments. Milder forms of the disorder, including the Weber-Cockayne and Koebner types, are often caused by mutations in less critical regions. Epidermis bullosa simplex with mottled pigmentation typically results from a particular KRT5 mutation. This mutation replaces the amino acid proline with the amino acid leucine at protein position 25 (written as Pro25Leu or P25L).
The KRT5 mutations responsible for epidermolysis bullosa simplex change the structure and function of keratin 5, preventing it from working effectively with keratin 14 and interfering with the assembly of the keratin intermediate filament network. A disruption in this network makes keratinocytes fragile and prone to rupture. Minor trauma to the skin, such as rubbing or scratching, can cause these cells to break down, resulting in the formation of painful, fluid-filled blisters.
- other disorders - caused by mutations in the KRT5 gene
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At least three KRT5 mutations are responsible for a rare skin disorder called Dowling-Degos disease. This condition is characterized by a net-like (reticulate) pattern of dark skin pigmentation, particularly in the body's folds and creases. Although affected individuals do not experience blistering, they may develop dark bumps or thickened patches of skin on the neck and back. The mutations that cause Dowling-Degos disease lead to the production of an abnormally small, nonfunctional version of keratin 5. Studies suggest that a loss of this protein may disrupt the movement of pigment-carrying melanosomes into keratinocytes, where they are needed for normal skin pigmentation.
Where is the KRT5 gene located?
Cytogenetic Location: 12q12-q13
Molecular Location on chromosome 12: base pairs 51,194,627 to 51,200,509
The KRT5 gene is located on the long (q) arm of chromosome 12 between positions 12 and 13.
More precisely, the KRT5 gene is located from base pair 51,194,627 to base pair 51,200,509 on chromosome 12.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about KRT5?
You and your healthcare professional may find the following resources about KRT5 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
- PubMed
- Recent literature
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OMIM - Genetic disorder catalog (2 links)
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What other names do people use for the KRT5 gene or gene products?
- CK5
- cytokeratin 5
- EBS2
- K2C5_HUMAN
- K5
- 58 kda cytokeratin
- Keratin-5
- keratin, type II cytoskeletal 5
- KRT5A
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding KRT5?
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? in the Handbook.