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KCNB1 gene

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

KCNB1 gene

The KCNB1 gene provides instructions for creating potassium channels that regulate electrical signaling in the brain, and mutations in this gene are linked to a condition known as KCNB1 encephalopathy.

Normal Function

The KCNB1 gene belongs to a large family of genes that provide instructions for making potassium channels. These channels transport positively charged potassium ions in and out of cells, playing a key role in a cell's ability to generate and transmit electrical signals.

The KCNB1 gene provides instructions for making one part of a potassium channel called Kv2.1. These channels are found primarily in nerve cells (neurons) in the brain, where they transport potassium ions out of neurons. The flow of ions through these channels regulates the activity of neurons and facilitates communication between these cells.

Health Conditions Related to Genetic Changes

KCNB1 encephalopathy

More than 45 mutations in the KCNB1 gene have been found to cause KCNB1 encephalopathy. This condition is characterized by abnormal brain function (encephalopathy), recurrent seizures (epilepsy), and developmental delay.

Most KCNB1 gene mutations change single amino acids, while others introduce a premature stop signal, resulting in a shortened, nonfunctional protein. All KCNB1 gene mutations impair Kv2.1 channel function. Because the channels cannot properly regulate the flow of potassium ions, communication between neurons is disrupted, leading to impaired brain development, seizures, and intellectual disability.

Other Names for This Gene

  • DEE26
  • DRK1
  • Kv2.1
  • potassium channel, voltage-gated, shab-related subfamily, member 1

Genomic Location

The KCNB1 gene is found on chromosome 20.

Frequently Asked Questions

Diagnosis usually begins with clinical observation of developmental delay, intellectual disability, and recurrent seizures (epilepsy). Because the condition is genetic, definitive diagnosis requires genetic testing, specifically sequencing of the KCNB1 gene on chromosome 20. Clinicians may also use electroencephalography (EEG) to characterize seizure activity and brain imaging to rule out other structural causes of encephalopathy, but the genetic confirmation is the gold standard for identifying the specific mutation.
There is no cure for KCNB1 encephalopathy, so treatment focuses on symptom management. Antiepileptic drugs (AEDs) are the mainstay of therapy to control seizures, though response rates can vary among patients. Some individuals may require multiple medications or, in severe cases, surgical interventions such as vagus nerve stimulation or dietary therapies like the ketogenic diet. Early intervention services, including physical, occupational, and speech therapy, are also critical to maximize developmental potential and functional independence.
Most cases of KCNB1 encephalopathy are caused by de novo (new) mutations, meaning they occur spontaneously and are not inherited from a parent. However, in rare instances, a parent may carry a mutation with mild or no symptoms. Genetic counseling is recommended for affected families to assess recurrence risk. If a parent is found to carry a mutation, the risk of passing it to offspring is 50% for each pregnancy, and options such as preimplantation genetic testing (PGT) or prenatal diagnosis may be discussed.
The Kv2.1 channel is responsible for transporting potassium ions out of neurons, which is essential for resetting the electrical charge after a neuron fires. When KCNB1 mutations impair this channel, neurons cannot properly regulate their activity, leading to excessive excitability and disrupted communication between brain cells. This chronic disruption interferes with normal brain maturation and synaptic pruning during critical developmental windows, resulting in the observed encephalopathy, intellectual disability, and persistent seizure activity.
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.