KCNJ3 is a gene that provides instructions for making a protein known as an inwardly rectifying potassium channel. This protein plays a crucial role in regulating the flow of potassium ions in and out of cells, which is essential for maintaining the electrical balance and proper functioning of various tissues, particularly in the heart and brain. Mutations in the KCNJ3 gene can lead to health issues, including certain types of cardiac arrhythmias. Research on KCNJ3 is important for understanding its role in conditions like Long QT syndrome and for developing potential treatments that target potassium channels to restore normal heart rhythms.