All of the following are neurologic channelopathies, except?
**Core Concept**
Neurologic channelopathies are disorders caused by mutations in genes encoding ion channels, leading to abnormal electrical activity in neurons and other excitable tissues. These conditions can result in a wide range of symptoms, including muscle weakness, seizures, and cardiac arrhythmias.
**Why the Correct Answer is Right**
To determine which option is not a neurologic channelopathy, we must first identify the conditions associated with ion channel dysfunction. *Hypokalemic periodic paralysis* (A) is caused by mutations in genes encoding calcium channels, leading to abnormal muscle excitability. *Epilepsy* (B) can be caused by mutations in genes encoding various ion channels, including sodium, potassium, and calcium channels. *Hyperkalemic periodic paralysis* (C) is caused by mutations in genes encoding sodium channels.
**Why Each Wrong Option is Incorrect**
**Option A:** is not a neurologic channelopathy, but rather a muscular disorder caused by mutations in the SCN5A gene encoding a cardiac sodium channel. While it affects the nervous system indirectly, it is primarily a cardiac condition.
**Clinical Pearl / High-Yield Fact**
Ion channelopathies are a diverse group of disorders that can affect the nervous system, heart, and muscles. Remember the " Channelopathies: Calcium, Sodium, Potassium" mnemonic to associate these ions with the conditions they are linked to.
**Correct Answer:** A. Hypokalemic periodic paralysis is not a neurologic channelopathy.