Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. Inward rectifier potassium channel 2 encoded by KCNJ2 is an integral membrane protein and inward-rectifier type potassium channel. Inward rectifier potassium channel 2, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, probably participates in establishing action potential waveform and excitability of neuronal and muscle tissues. Mutations in this gene have been associated with Andersen syndrome, which is characterized by periodic paralysis, cardiac arrhythmias, and dysmorphic features.