Channelopathies are rare genetic or acquired diseases that affect the cell membrane channels. In broad terms, what effects do think channelopathies have (i.e. what symptoms would they produce)?

Membrane channels play an essential role in cell membrane function, and the cell membrane plays an essential role in cell function. Channelopathies will affect membrane and therefore cell function. The symptoms that are produced will depend on the channels that are affected,  their role in the cell, and the function of the cell in the body. Movement of ions through cell membrane channels creates electrical currents and generates the membrane potential essential for the production of action potentials in nerves and contraction of muscles (you will hear more about this later in the semester) and other functions such as  signal transduction, neurotransmitter release, hormone secretion, volume regulation, growth and motility. In the muscle they can cause problems ranging from myotonia (muscle hyperexcitability) to flaccid paralysis (muscle hypoexcitability). Channelopathies in the heart cause sudden death due to irregular electrical activity, and are probably contribute to many cases of SIDS.