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SCNN1B gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SCNN1B gene

The SCNN1B gene encodes the beta subunit of the epithelial sodium channel (ENaC), a protein complex critical for maintaining sodium and fluid homeostasis in various tissues.

Normal Function

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. These channels are found at the surface of epithelial cells in tissues including the kidneys, lungs, colon, and sweat glands. The ENaC channel transports sodium into cells.

In the kidney, ENaC channels open when blood sodium levels are low, allowing sodium to flow into cells and return to the bloodstream (reabsorption) instead of being excreted in urine. This process also helps control the movement of water in tissues, such as regulating fluid levels in the lungs.

Health Conditions Related to Genetic Changes

Liddle syndrome

At least 16 mutations in the SCNN1B gene can cause Liddle syndrome, which is characterized by childhood-onset hypertension and hypokalemia.

  • Mutations result in an abnormally short beta subunit protein or the replacement of a single amino acid.
  • These changes disrupt the region of the protein involved in degradation signaling.
  • The protein is not broken down, causing an accumulation of ENaC channels at the cell surface.
  • This leads to excessive sodium and water reabsorption, causing hypertension and the subsequent removal of potassium from the blood (hypokalemia).

Pseudohypoaldosteronism type 1

Mutations in the SCNN1B gene are associated with pseudohypoaldosteronism type 1 (PHA1), a condition characterized by hyponatremia, hyperkalemia, and severe dehydration in infancy.

  • These mutations often result in a single amino acid replacement or an abnormally short protein.
  • The mutations cause reduced or absent ENaC channel activity, impairing sodium reabsorption.
  • Reduced ENaC function in lung epithelial cells leads to excess fluid in the lungs and recurrent lung infections.

Other disorders

Some individuals with cystic fibrosis-like syndrome (atypical cystic fibrosis or bronchiectasis with or without elevated sweat chloride type 1) have mutations or variations in the SCNN1B gene. These individuals experience symptoms similar to cystic fibrosis, such as breathing problems and lung infections, despite having no mutations in the CFTR gene. The SCNN1B variations are thought to disrupt sodium transport and fluid balance.

Other Names for This Gene

  • 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, non voltage gated 1 beta subunit
  • sodium channel, non-voltage-gated 1, beta subunit
  • sodium channel, nonvoltage-gated 1, beta

Frequently Asked Questions

Liddle syndrome usually presents with high blood pressure and low potassium, whereas PHA1 shows low sodium, high potassium, and severe dehydration. Blood chemistry and genetic testing for SCNN1B mutations will clarify the diagnosis. What are the main treatment differences for infants with PHA1 compared to older patients with Liddle syndrome?::Infants with PHA1 need aggressive sodium replacement and careful fluid management, often via intravenous or high‑salt oral solutions, while older patients with Liddle syndrome are managed with potassium‑sparing diuretics and low‑salt diets. Is genetic counseling recommended for families with a known SCNN1B mutation?::Absolutely. Since both Liddle syndrome and PHA1 are inherited in an autosomal dominant pattern, a genetic counselor can explain recurrence risks, offer carrier testing, and discuss prenatal testing options. What monitoring should parents expect for a child diagnosed with a SCNN1B mutation?::Regular checks of blood pressure, serum electrolytes (sodium, potassium), and kidney function are essential. In infants, frequent weight and hydration status assessments are also critical to catch dehydration early.
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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