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SCNN1A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SCNN1A gene

The SCNN1A gene provides instructions for making a subunit of the epithelial sodium channel, which is essential for regulating sodium and fluid balance in tissues like the kidneys and lungs.

Normal Function

The SCNN1A gene provides instructions for making one piece, the alpha 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, and sweat glands. The ENaC channel transports sodium into cells.

In the kidney, ENaC channels take sodium into cells in response to signals that sodium levels in the body are too low. From the kidney cells, this sodium is returned to the bloodstream rather than being removed from the body (a process called reabsorption). 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.

Health Conditions Related to Genetic Changes

Pseudohypoaldosteronism type 1

At least a dozen mutations in the SCNN1A gene cause 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. In particular, SCNN1A gene mutations are involved in autosomal recessive PHA1, a severe form of the condition that does not improve with age.

Most mutations in the SCNN1A gene result in a shortened alpha subunit protein of the ENaC channel. SCNN1A gene mutations lead to 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

Some people with cystic fibrosis-like syndrome have a mutation or a normal gene variation (polymorphism) in the SCNN1A gene. People with cystic fibrosis-like syndrome (also known as atypical cystic fibrosis or bronchiectasis with or without elevated sweat chloride type 2) have signs and symptoms that resemble those of cystic fibrosis, including breathing problems and lung infections. It is thought that a mutation or gene variation in the SCNN1A gene can disrupt sodium transport and fluid balance, which leads to the signs and symptoms of cystic fibrosis-like syndrome.

Other Names for This Gene

  • alpha-ENaC
  • alpha-NaCH
  • amiloride-sensitive epithelial sodium channel alpha subunit
  • amiloride-sensitive sodium channel subunit alpha
  • BESC2
  • ENaCa
  • ENaCalpha
  • epithelial Na(+) channel subunit alpha
  • FLJ21883
  • nasal epithelial sodium channel alpha subunit
  • nonvoltage-gated sodium channel 1 subunit alpha
  • SCNEA
  • SCNN1
  • SCNNA_HUMAN
  • sodium channel, non voltage gated 1 alpha subunit
  • sodium channel, non-voltage-gated 1 alpha subunit
  • sodium channel, nonvoltage-gated 1 alpha

Frequently Asked Questions

Diagnosis typically begins when an infant presents with severe dehydration, poor feeding, or failure to thrive. Clinicians will order blood tests to check for hyponatremia (low sodium) and hyperkalemia (high potassium), along with elevated aldosterone levels. To confirm the genetic cause, molecular testing is performed to identify specific mutations in the SCNN1A gene. This distinguishes the autosomal recessive form from the milder autosomal dominant form, which often improves with age.
The primary immediate risks are severe electrolyte imbalances, specifically dangerous drops in blood sodium and spikes in blood potassium. Hyperkalemia can lead to cardiac arrhythmias and heart failure, while severe hyponatremia can cause seizures and brain swelling. Additionally, the inability to retain sodium leads to profound dehydration, which can result in shock if not treated promptly with intravenous fluids and electrolyte replacement.
No, diet alone is insufficient for managing autosomal recessive pseudohypoaldosteronism type 1. While a high-sodium diet is a critical part of the long-term management strategy to compensate for the body's inability to reabsorb sodium efficiently, it must be combined with rigorous medical monitoring. Patients often require regular supplementation and close tracking of blood electrolyte levels to prevent dangerous fluctuations that dietary changes cannot fully control.
The SCNN1A gene produces the alpha subunit of the epithelial sodium channel, which is present in lung cells. In healthy individuals, these channels help regulate fluid balance by moving sodium and water out of the airways. Mutations that disrupt this channel can impair the lung's ability to clear fluid, potentially leading to respiratory distress or complications in fluid regulation within the pulmonary tissue, although the primary clinical presentation usually focuses on renal and electrolyte issues.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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