Channelopathies
A variety of neuromuscular conditions resulting from MUTATIONS in ION CHANNELS manifesting as episodes of EPILEPSY; HEADACHE DISORDERS; and DYSKINESIAS.
Paralyses, Familial Periodic
A heterogenous group of inherited disorders characterized by recurring attacks of rapidly progressive flaccid paralysis or myotonia. These conditions have in common a mutation of the gene encoding the alpha subunit of the sodium channel in skeletal muscle. They are frequently associated with fluctuations in serum potassium levels. Periodic paralysis may also occur as a non-familial process secondary to THYROTOXICOSIS and other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1481)
Hypokalemic Periodic Paralysis
An autosomal dominant familial disorder characterized by recurrent episodes of skeletal muscle weakness associated with falls in serum potassium levels. The condition usually presents in the first or second decade of life with attacks of trunk and leg paresis during sleep or shortly after awakening. Symptoms may persist for hours to days and generally are precipitated by exercise or a meal high in carbohydrates. (Adams et al., Principles of Neurology, 6th ed, p1483)
Myotonic Disorders
Myotonia
Prolonged failure of muscle relaxation after contraction. This may occur after voluntary contractions, muscle percussion, or electrical stimulation of the muscle. Myotonia is a characteristic feature of MYOTONIC DISORDERS.
Paralysis, Hyperkalemic Periodic
An autosomal dominant familial disorder which presents in infancy or childhood and is characterized by episodes of weakness associated with hyperkalemia. During attacks, muscles of the lower extremities are initially affected, followed by the lower trunk and arms. Episodes last from 15-60 minutes and typically occur after a period of rest following exercise. A defect in skeletal muscle sodium channels has been identified as the cause of this condition. Normokalemic periodic paralysis is a closely related disorder marked by a lack of alterations in potassium levels during attacks of weakness. (Adams et al., Principles of Neurology, 6th ed, p1481)
Isaacs Syndrome
A rare neuromuscular disorder with onset usually in late childhood or early adulthood, characterized by intermittent or continuous widespread involuntary muscle contractions; FASCICULATION; hyporeflexia; MUSCLE CRAMP; MUSCLE WEAKNESS; HYPERHIDROSIS; TACHYCARDIA; and MYOKYMIA. Involvement of pharyngeal or laryngeal muscles may interfere with speech and breathing. The continuous motor activity persists during sleep and general anesthesia (distinguishing this condition from STIFF-PERSON SYNDROME). Familial and acquired (primarily autoimmune) forms have been reported. (From Ann NY Acad Sci 1998 May 13;841:482-496; Adams et al., Principles of Neurology, 6th ed, p1491)
Long QT Syndrome
A condition that is characterized by episodes of fainting (SYNCOPE) and varying degree of ventricular arrhythmia as indicated by the prolonged QT interval. The inherited forms are caused by mutation of genes encoding cardiac ion channel proteins. The two major forms are ROMANO-WARD SYNDROME and JERVELL-LANGE NIELSEN SYNDROME.
NAV1.5 Voltage-Gated Sodium Channel
NAV1.4 Voltage-Gated Sodium Channel
A voltage-gated sodium channel subtype that mediates the sodium ion PERMEABILITY of SKELETAL MYOCYTES. Defects in the SCN4A gene, which codes for the alpha subunit of this sodium channel, are associated with several MYOTONIC DISORDERS.
Sodium Channels
Brugada Syndrome
An autosomal dominant defect of cardiac conduction that is characterized by an abnormal ST-segment in leads V1-V3 on the ELECTROCARDIOGRAM resembling a right BUNDLE-BRANCH BLOCK; high risk of VENTRICULAR TACHYCARDIA; or VENTRICULAR FIBRILLATION; SYNCOPAL EPISODE; and possible sudden death. This syndrome is linked to mutations of gene encoding the cardiac SODIUM CHANNEL alpha subunit.
Myopathy, Central Core
An inherited congenital myopathic condition characterized by weakness and hypotonia in infancy and delayed motor development. Muscle biopsy reveals a condensation of myofibrils and myofibrillar material in the central portion of each muscle fiber. (Adams et al., Principles of Neurology, 6th ed, p1452)
Nervous System Diseases
Ion Channels
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
Sudden Infant Death
The abrupt and unexplained death of an apparently healthy infant under one year of age, remaining unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history. (Pediatr Pathol 1991 Sep-Oct;11(5):677-84)
Genetic Diseases, Inborn
Arrhythmias, Cardiac
Malignant Hyperthermia
Mutation
Potassium Channels, Inwardly Rectifying
Ion Channel Gating
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
Potassium Channels, Voltage-Gated
Death, Sudden, Cardiac
Unexpected rapid natural death due to cardiovascular collapse within one hour of initial symptoms. It is usually caused by the worsening of existing heart diseases. The sudden onset of symptoms, such as CHEST PAIN and CARDIAC ARRHYTHMIAS, particularly VENTRICULAR TACHYCARDIA, can lead to the loss of consciousness and cardiac arrest followed by biological death. (from Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., 2005)
Calcium Channels
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
Ajmaline
Electrocardiography
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.