Ion channels diseases

Ackerman, M.J., The long QT syndrome ion channel diseases of the heart, Mayo Clin. Proc., 73, 250-269, 1998. 

Ion channel diseases Sodium transport High sweat chloride. 

Dysfunction of ion channels causes many diseases. Some ion channel diseases are genetic. Channelopathies are caused directly by mutatimis in genes coding for ion channels [4—7]. Examples of channelopathies are cystic fibrosis, epilepsy, and arrhythmias such as the long QT syndrome. Some other ion channels may be involved in nongenetic diseases such as dianfiea, which is mediated by toxicological effects on ion channel function [8]. 

Some diseases caused by mutations of ion channels are briefly discussed in Chapter 49. 

Mutations that affect the structure of membrane proteins (teceptots, ttanspotters, ion channels, enzymes, and stmctutal proteins) may cause diseases examples include cystic fibrosis and familial hypetcholes-terolemia. 

Data in part from Ackerman NJ, Clapham DE Ion channels— basic science and clinical disease. N Engl J Med 1997,-336 1575. Other channelopathies include the long QT syndrome (MIM 192500) pseudoaldosteronism (Liddle syndrome, MIM 177200) persistent hyperinsulinemic hypoglycemia of infancy (MIM 601820) hereditary X-linked recessive type II nephrolithiasis of infancy (Dent syndrome, MIM 300009) and generalized myotonia, recessive (Becker disease, MIM 255700). The term "myotonia" signifies any condition in which muscles do not relax after contraction. 

Ackerman MJ, Clapham DE Ion channels—basic science and clinical disease. N Engl J Med 1997 336 1575. 

Lehmann-Horn, F. and Jurkat-Rott, K. Voltage-gated ion channels and hereditary disease. Physiol Rev. 79 1317-1372, 1999. 

One model of an ionic mechanism of action of Li+ in affective disorders has been proposed, in which the receptors for Li+ are ion channels and cation coenzyme receptor sites, and in which the presence of intracellular Li+ in excitable cells results in the displacement of exogenous Na+ and/or other intracellular cations [13]. It has been suggested that this could lead to a decrease in the release of neurotransmitters alternatively it may be that this intracellular Li+ is altering a preexisting, disease-related electrolyte imbalance [14]. A number of observations of such imbalances in affective disorders have been made depression is associated with elevated levels of intracellular Na+ [15] retention of Li+ is observed in manic-depressive patients prior to an episode of mania [ 16] and Na+/K+ activity is defective during both mania and depression [17]. 

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