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The official name of this gene is “keratin 1, type II.”
KRT1 is the gene's official symbol. The KRT1 gene is also known by other names, listed below.
The KRT1 gene provides instructions for making a protein called keratin 1. Keratins are a group of tough, fibrous proteins that form the structural framework of cells called keratinocytes that make up the skin, hair, and nails. Keratin 1 is produced in keratinocytes in the outer layer of the skin (the epidermis), including the skin on the palms of the hands and soles of the feet.
The keratin 1 protein partners with another keratin protein, either keratin 9 or keratin 10, to form molecules called keratin intermediate filaments. These filaments assemble into strong networks that provide strength and resiliency to the skin and protect it from being damaged by friction and other everyday physical stresses.
The KRT1 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.
Dozens of mutations in the KRT1 gene have been found in people with epidermolytic hyperkeratosis. This condition is a skin disorder characterized by red, blistering skin at an early age and thick skin (hyperkeratosis) later in life. People with KRT1 gene mutations typically have PS-type epidermolytic hyperkeratosis, which features thick skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis) in addition to other parts of the body.
Most KRT1 gene mutations associated with epidermolytic hyperkeratosis change a single protein building block (amino acid) in the keratin 1 protein. These amino acid changes commonly occur in regions of the protein that play a role in intermediate filament formation. The mutations alter the keratin 1 protein and seem to affect how intermediate filaments interact with each other to form networks. The altered proteins still form intermediate filaments, but the intermediate filament networks are weaker and do not function normally. Without a strong network, skin cells become fragile and are easily damaged, which can lead to blistering in response to friction or mild trauma. It is unclear how these mutations cause the overgrowth of keratinocytes that results in hyperkeratotic skin.
KRT1 gene mutations are involved in many other skin disorders. In several of these conditions, there is palmoplantar hyperkeratosis, but the skin on other parts of the body is usually not affected. A condition called epidermolytic palmoplantar keratoderma caused by KRT1 gene mutations is relatively mild. Affected individuals typically have palmoplantar hyperkeratosis with detachment or loosening of the epidermis (epidermolysis), usually seen as blistering. People with nonepidermolytic palmoplantar keratoderma have palmoplantar hyperkeratosis with no evidence of epidermolysis. In striate palmoplantar keratoderma type 3, the skin thickening on the palms and soles follows a specific pattern.
KRT1 gene mutations are also responsible for a skin disorder called Curth-Macklin ichthyosis hystrix. This condition involves severe hyperkeratosis on the palms and soles and sometimes the skin over large joints or on the torso. This condition is distinguished by specific changes in the keratinocytes.
Another skin condition caused by genetic changes in the KRT1 gene called cyclic ichthyosis with epidermolytic hyperkeratosis is similar to epidermolytic hyperkeratosis, but the skin changes disappear for short periods, then recur. The recurrent skin changes can last for weeks or months.
Cytogenetic Location: 12q13.13
Molecular Location on chromosome 12: base pairs 52,674,735 to 52,680,406
The KRT1 gene is located on the long (q) arm of chromosome 12 at position 13.13.
More precisely, the KRT1 gene is located from base pair 52,674,735 to base pair 52,680,406 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 KRT1 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.
amino acid ; cytokeratin ; epidermis ; gene ; ichthyosis ; intermediate filaments ; keratin ; keratoderma ; palmoplantar keratoderma ; protein ; trauma
You may find definitions for these and many other terms in the Genetics Home Reference 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.