News on ion channels: erythromelalgia, treatment of episodic ataxia and faciobrachial dystonic seizures

Excerpt

A large variety of neurological disorders, including myopathies, peripheral nerve disorders, different forms of epilepsy, hemiplegic migraine and limbic encephalitis, can now be classified as ion-channel disorders. Due to our detailed knowledge of the function and dysfunction of the different types of ion channels, the pathophysiology of many of these disorders has been thoroughly evaluated and this has also led to the development of new therapeutics and therapeutic principles. This month’s Journal Club will focus on three recent articles in this field. The first deals with a specific mutation of the sodium channel in inherited erythromelalgia, which leads to shifts in activation and in slow inactivation which modulates the neuron hyperexcitability. These findings could be correlated with the clinical presentation and the effectiveness of certain pharmacological agents. In the second article, a new therapeutic principle for the prophylactic treatment of episodic ataxia type 2 is described: the use of the potassium channel blocker 4-aminopyridine, which is evidently a reasonable alternative to acetazolamide. In the third article, it is clearly shown that faciobrachial dystonic seizures precede voltage-gated potassium channel antibody limbic encephalitis. This type of epilepsy does not respond to antiepileptic drugs, but to immunotherapies, which is of clinical relevance in this specific form of epileptic seizures. …