KCNJ2 is a gene that provides instructions for making a protein called potassium ion channel. This protein is essential for maintaining the electrical balance in cells, particularly in the heart and brain. It helps regulate the flow of potassium ions, which are crucial for proper cell function and communication. Mutations in the KCNJ2 gene can lead to various health issues, including Andersen-Tawil syndrome, a condition characterized by heart rhythm problems, muscle weakness, and distinctive physical features. Understanding KCNJ2 is important for diagnosing and managing these genetic disorders effectively.