A form of inherited long qt syndrome (or LQT7) that is characterized by a triad of potassium-sensitive periodic paralysis, VENTRICULAR ECTOPIC BEATS, and abnormal features such as short stature, low-set ears, and scoliosis. It results from mutations of KCNJ2 gene which encodes a channel protein (INWARD RECTIFIER potassium channels) that regulates resting membrane potential.