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The official name of this gene is “espin.”
ESPN is the gene's official symbol. The ESPN gene is also known by other names, listed below.
The ESPN gene provides instructions for making a protein called espin. This protein is active in the inner ear, where it appears to play an essential role in normal hearing and balance. Researchers believe that espin binds to actin, a protein that is important for cell movement and shape. Espin is probably involved in the growth and maintenance of hairlike projections called stereocilia. Stereocilia, which are rich in actin, line the inner ear and bend in response to sound waves. This bending motion is essential for converting sound waves to nerve impulses and for conveying information about the body's position and movement.
Espin may also play a role in other types of sensory cells. Some studies suggest that this protein is present in taste receptor cells, cells involved in recognizing smells, and Merkel cells in the skin, which are associated with the sense of touch. In these cells, espin is located in small, fingerlike structures called microvilli that project from the cell surface. Like stereocilia in the inner ear, microvilli contain a large amount of actin.
The ESPN gene belongs to a family of genes called ANKRD (ankyrin repeat domain containing).
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 ESPN gene have been identified in people with a form of nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body) called DFNB36. Several of these mutations cause an autosomal recessive form of nonsyndromic deafness that includes problems with balance. Autosomal recessive inheritance means that two copies of the gene in each cell are altered. These genetic changes delete a small amount of DNA from critical regions of the ESPN gene. Researchers believe that these genetic changes may prevent the production of espin or lead to an abnormally small, nonfunctional version of the protein that cannot bind to actin. A loss of espin function likely disrupts the development, structure, and organization of stereocilia, leading to hearing loss and balance problems.
Other ESPN mutations cause an autosomal dominant form of nonsyndromic hearing loss without obvious balance problems. Autosomal dominant inheritance means that one altered copy of the gene in each cell is sufficient to cause the condition. Most of these mutations alter a single protein building block (amino acid) in espin, which probably changes the structure of the protein. Although researchers have not determined how these mutations lead to hearing loss, they suspect that the altered protein disrupts the growth and organization of stereocilia in the inner ear.
Cytogenetic Location: 1p36.31
Molecular Location on chromosome 1: base pairs 6,424,775 to 6,460,943
The ESPN gene is located on the short (p) arm of chromosome 1 at position 36.31.
More precisely, the ESPN gene is located from base pair 6,424,775 to base pair 6,460,943 on chromosome 1.
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 ESPN 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.
actin ; amino acid ; autosomal ; autosomal dominant ; autosomal recessive ; cell ; DNA ; gene ; inheritance ; microvilli ; protein ; receptor ; recessive ; sensory cells
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (/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.