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SCNN1B

SCNN1B

Reviewed March 2013

What is the official name of the SCNN1B gene?

The official name of this gene is “sodium channel, non-voltage-gated 1, beta subunit.”

SCNN1B is the gene's official symbol. The SCNN1B gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the SCNN1B gene?

The SCNN1B gene provides instructions for making one piece, the beta subunit, of a protein complex called the epithelial sodium channel (ENaC). The channel is composed of alpha, beta, and gamma subunits, each of which is produced from a different gene. These channels are found at the surface of certain cells called epithelial cells in many tissues of the body, including the kidneys, lungs, colon, and sweat glands. The ENaC channel transports sodium into cells.

In the kidney, ENaC channels open in response to signals that sodium levels in the blood are too low, which allows sodium to flow into cells. From the kidney cells, this sodium is returned to the bloodstream (a process called reabsorption) rather than being removed from the body in urine. In addition to regulating the amount of sodium in the body, the flow of sodium ions helps control the movement of water in tissues. For example, ENaC channels in lung cells help regulate the amount of fluid in the lungs.

Does the SCNN1B gene share characteristics with other genes?

The SCNN1B gene belongs to a family of genes called SC (sodium channels).

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 SCNN1B gene related to health conditions?

Liddle syndrome - caused by mutations in the SCNN1B gene

At least 16 mutations in the SCNN1B gene can cause a condition known as Liddle syndrome. People with Liddle syndrome have high blood pressure (hypertension) and low levels of potassium in their blood (hypokalemia), often beginning in childhood. Mutations in the SCNN1B gene associated with Liddle syndrome lead to the production of an abnormally short beta subunit protein or result in the replacement of a single protein building block (amino acid) in the protein. These changes affect an important region of the protein involved in signaling for its breakdown (degradation). As a result of the mutations, the protein is not degraded, and more ENaC channels remain at the cell surface. The increase in channels at the cell surface abnormally increases the reabsorption of sodium (followed by water), which leads to hypertension. Reabsorption of sodium into the blood is linked with removal of potassium from the blood, so excess sodium reabsorption leads to hypokalemia.

pseudohypoaldosteronism type 1 - caused by mutations in the SCNN1B gene

Mutations in the SCNN1B gene have been identified in people with pseudohypoaldosteronism type 1 (PHA1). This condition typically begins in infancy and is characterized by low levels of sodium (hyponatremia) and high levels of potassium (hyperkalemia) in the blood, and severe dehydration due to the loss of excess sodium and fluid in urine. In particular, SCNN1B gene mutations are involved in autosomal recessive PHA1, a severe form of the condition that does not improve with age.

Mutations in the SCNN1B gene that cause PHA1 often result in the replacement of a single amino acid in the beta subunit protein or lead to an abnormally short protein. These mutations result in reduced or absent ENaC channel activity. As a result, sodium reabsorption is impaired, leading to hyponatremia and other signs and symptoms of autosomal recessive PHA1. The reduced function of ENaC channels in lung epithelial cells leads to excess fluid in the lungs and recurrent lung infections.

other disorders - associated with the SCNN1B gene

Some people with cystic fibrosis-like syndrome have a mutation or a normal gene variation (polymorphism) in the SCNN1B gene. People with cystic fibrosis-like syndrome (also known as atypical cystic fibrosis or bronchiectasis with or without elevated sweat chloride type 1) have signs and symptoms that resemble those of cystic fibrosis, including breathing problems and lung infections. However, changes in the gene most commonly associated with cystic fibrosis, CFTR, cannot explain development of the condition. It is thought that a mutation or gene variation in the SCNN1B gene can disrupt sodium transport and fluid balance, which leads to the signs and symptoms of cystic fibrosis-like syndrome.

Where is the SCNN1B gene located?

Cytogenetic Location: 16p12.2-p12.1

Molecular Location on chromosome 16: base pairs 23,302,269 to 23,381,298

The SCNN1B gene is located on the short (p) arm of chromosome 16 between positions 12.2 and 12.1.

The SCNN1B gene is located on the short (p) arm of chromosome 16 between positions 12.2 and 12.1.

More precisely, the SCNN1B gene is located from base pair 23,302,269 to base pair 23,381,298 on chromosome 16.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about SCNN1B?

You and your healthcare professional may find the following resources about SCNN1B helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the SCNN1B gene or gene products?

  • amiloride-sensitive sodium channel subunit beta
  • BESC1
  • beta-ENaC
  • beta-NaCH
  • ENaCb
  • ENaCbeta
  • epithelial Na(+) channel subunit beta
  • nasal epithelial sodium channel beta subunit
  • SCNEB
  • SCNNB_HUMAN
  • sodium channel, nonvoltage-gated 1, beta

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 SCNN1B?

amino acid ; atypical ; autosomal ; autosomal recessive ; breakdown ; bronchiectasis ; cell ; channel ; chloride ; colon ; degradation ; dehydration ; epithelial ; fibrosis ; gene ; hyperkalemia ; hypertension ; hypokalemia ; hyponatremia ; ions ; kidney ; mutation ; Na ; polymorphism ; potassium ; protein ; recessive ; sodium ; sodium channel ; subunit ; syndrome ; voltage

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (16 links)

 

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.

 
Reviewed: March 2013
Published: August 25, 2014