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KCNH2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

KCNH2 gene

The KCNH2 gene is responsible for creating potassium channels that regulate the heart's electrical rhythm, and mutations in this gene are associated with long QT syndrome, short QT syndrome, and other heart conditions.

Normal Function

The KCNH2 gene provides instructions for making potassium channels that transport potassium ions out of cells. Channels made with KCNH2 proteins (also known as hERG1) are active in heart muscle, where they help recharge the muscle after each heartbeat to maintain a regular rhythm. These proteins are also produced in nerve cells and certain immune cells (microglia) in the central nervous system.

The KCNH2 protein interacts with the KCNE2 gene product to form a functional channel. Four alpha subunits from the KCNH2 gene form the channel structure, while one beta subunit from the KCNE2 gene regulates its activity.

Health Conditions Related to Genetic Changes

Romano-Ward syndrome

Mutations in the KCNH2 gene account for approximately 25 percent of cases of Romano-Ward syndrome, the most common form of long QT syndrome. These mutations prevent the protein from assembling into ion channels or alter their function, causing the heart muscle to take longer than usual to recharge. This increases the risk of an irregular heartbeat, fainting (syncope), or sudden death.

Short QT syndrome

Mutations in the KCNH2 gene can also cause short QT syndrome, where the heart muscle recharges too quickly. These mutations increase the activity of the ion channels, causing excessive potassium flow out of cardiac cells, which can lead to an irregular heartbeat and sudden death.

Other disorders

A small percentage of cases of acquired long QT syndrome—a drug-induced condition that increases the risk of cardiac arrest—occur in people with an underlying variation in the KCNH2 gene.

Other Names for This Gene

  • ERG1
  • ether-a-go-go related gene potassium channel 1
  • H-ERG
  • HERG
  • HERG1
  • human ether a-go-go-related gene
  • KCNH2_HUMAN
  • Kv11.1
  • LQT2
  • potassium channel, voltage gated eag related subfamily H, member 2
  • potassium voltage-gated channel, subfamily H (eag-related), member 2

Genomic Location

The KCNH2 gene is found on chromosome 7.

Frequently Asked Questions

voiding high‑intensity exercise that can provoke arrhythmias, staying hydrated, maintaining normal electrolyte levels (especially potassium and magnesium), and avoiding sudden changes in heart rate (e.g., abrupt standing) can reduce risk. Regular follow‑up with a cardiologist for ECGs and Holter monitoring is also advised.
Yes. Many drugs—including some antibiotics, antipsychotics, anti‑arrhythmics, and macrolide antibiotics—can prolong the QT interval. Patients with KCNH2 mutations should avoid these medications or use them only under close cardiology supervision and with ECG monitoring.
If a family member has a KCNH2 mutation, it is recommended that first‑degree relatives undergo genetic counseling and, if appropriate, genetic testing. Early identification allows for ECG screening, lifestyle modifications, and medication review to reduce the risk of arrhythmias.
n ICD may be considered for individuals who have survived a cardiac arrest, have documented sustained ventricular tachycardia, or have a very prolonged QT interval despite medication and lifestyle measures. The decision is individualized and made after thorough risk assessment by a cardiologist.===
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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