Hypokalemic periodic paralysis is a familial condition caused by missense mutations of voltage sensor domains within L-type calcium channels or the skeletal Na+ channel. Must know: Thyrotoxic Periodic Paralysis: Redistributive hypokalemia occurs in the setting of hypehyroidism. It can cause periodic attacks of hypokalemic paralysis - (TPP). Patients typically present with weakness of the extremities and limb girdles. Paralytic episodes occur most frequently between 1 and 6 a.m. Signs and symptoms of hypehyroidism are usually not seen. Ref: Harrison, Edition-18, page- 352.