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The official name of this gene is “keratin 4, type II.”
KRT4 is the gene's official symbol. The KRT4 gene is also known by other names, listed below.
The KRT4 gene provides instructions for making a protein called keratin 4. 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 4 is found in the moist lining (mucosae) of the mouth, nose, esophagus, genitals, and anus.
Keratin 4 partners with a similar protein, keratin 13 (produced from the KRT13 gene), to form molecules known as intermediate filaments. These filaments assemble into strong networks that provide strength and resilience to the different mucosae. Networks of intermediate filaments protect the mucosae from being damaged by friction or other everyday physical stresses.
The KRT4 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 six mutations in the KRT4 gene have been found to cause white sponge nevus, a condition that results in the formation of white patches of tissue called nevi (singular: nevus) that appear as thickened, velvety, sponge-like tissue. These nevi most often occur on the mouth (oral) mucosa (plural: mucosae). Rarely, white sponge nevus occurs on the mucosae of the nose, esophagus, genitals, or anus.
The KRT4 gene mutations that cause white sponge nevus disrupt the structure of keratin 4. As a result, keratin 4 does not fit together properly with keratin 13, leading to the formation of irregular intermediate filaments that are easily damaged with little friction or trauma. Fragile intermediate filaments in the oral mucosa might be damaged when eating or brushing one's teeth. Damage to intermediate filaments leads to inflammation and promotes the abnormal growth and division (proliferation) of epithelial cells, causing the mucosae to thicken and resulting in white sponge nevus.
Cytogenetic Location: 12q13.13
Molecular Location on chromosome 12: base pairs 52,806,542 to 52,814,115
The KRT4 gene is located on the long (q) arm of chromosome 12 at position 13.13.
More precisely, the KRT4 gene is located from base pair 52,806,542 to base pair 52,814,115 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 KRT4 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.
anus ; cytokeratin ; epithelial ; esophagus ; gene ; genitals ; inflammation ; intermediate filaments ; keratin ; mucosa ; mucous ; mucous membrane ; proliferation ; protein ; resilience ; tissue ; trauma
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.