From http://www.kcnq.org/health/channelopathies.php

"When an ion channel goes wrong or does not function as it should, it may produce a disease in an individual. Certain forms of skeletal and cardiac muscle and brain diseases such as the myotonias, epilepsies, migraine or arrhythmias are due to pathological alterations in channel proteins and thus, can be considered as "Channelopathies".

" Another important cause of channelopathies is auto-immune attack. However, mutations in associated proteins, alterations in the expression of ion channels, and changes in the activity of
non-mutated channel genes or associated proteins can also produce what are known as acquired channelopathies. Such acquired channelopathies may occur as a result of nerve-injury or after drug treatments that perturb cellular function.
This huge variety in the causes of channelopathies, as varied as the diseases themselves, not only makes it difficult to study these diseases but it often makes the clinical diagnosis of these diseases problematic. "

"As stated, Channelopathies may also be due to the body producing antibodies that destroy specific ion channel proteins. These types of disease are known as autoimmune channelopathies of which myasthenia gravis and neuromyotonia are good examples. In these diseases, the antibodies mainly affect the function of the nicotinic acetylcholine receptors at the endplate and dendrotoxin-sensitive potassium channels, respectively. "