Related Experiment Video
Updated: Jul 31, 2026
08:16
Utility of Dissociated Intrinsic Hand Muscle Atrophy in the Diagnosis of Amyotrophic Lateral Sclerosis
Published on: March 4, 2014
Andersen's syndrome: a distinct periodic paralysis
V Sansone1, R C Griggs, G Meola
1Department of Neurology, University of Milan, S Donato Hospital, Italy.
Annals of Neurology
|October 23, 1997
Summary
Andersen's syndrome (AS) is a unique channelopathy impacting cardiac and skeletal muscles. Attacks of paralysis can occur with varying potassium levels, and prolonged QT intervals are a key feature.
Area of Science:
- Cardiovascular Medicine
- Neurology
- Genetics
Background:
- Andersen's syndrome (AS) is characterized by periodic paralysis, ventricular dysrhythmias, and dysmorphic features.
- AS is genetically distinct from common channelopathies affecting skeletal muscle sodium channels or cardiac potassium channels (LQT1).
Observation:
- Eleven additional patients from five kindreds with AS were studied.
- Paralysis attacks occurred with hypokalemia, normokalemia, or hyperkalemia in all patients.
- All patients exhibited similar dysmorphic features, and prolonged QT intervals were observed in all, regardless of symptoms.
Findings:
- Genetic linkage studies excluded known genetic loci for AS, including skeletal muscle sodium channels and LQT loci.
- Common mutations for hypokalemic periodic paralysis were absent in the studied patients.
- AS is confirmed as a unique channelopathy affecting both cardiac and skeletal membrane excitability, with paralysis potentially linked to any potassium level.
Implications:
- Prolonged QT interval is an integral feature of AS and can be the sole presenting sign.
- AS diagnosis requires careful consideration, especially to differentiate it from more common long QT syndromes (LQTS).
- Understanding AS's unique genetic basis is crucial for accurate diagnosis and management of affected individuals and families.
Related Concept Videos
01:26Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) is a severe tick-borne illness caused by Rickettsia rickettsii, a Gram-negative, coccobacillary bacterium. This pathogen is an obligate intracellular parasite, requiring a host cell for replication. Transmission occurs through the bite of an infected tick. In the United States, the most important vectors are Dermacentor variabilis (American dog tick) and Dermacentor andersoni (Rocky Mountain wood tick), though other tick species may also serve as vectors.
01:19Multiple Sclerosis l: Introduction
Multiple sclerosis is a chronic autoimmune disease of the central nervous system (CNS) that affects the brain, spinal cord, and optic nerves. It is an inflammatory demyelinating disorder and a leading cause of neurological disability in young adults.EpidemiologyMS commonly begins between 20 and 40 years of age and is twice as common in women. Its exact cause remains unclear, but genetic susceptibility contributes, with higher risk in first-degree relatives and identical twins. A greater...
01:22Epilepsy ll: Types
Recurrent seizures, stemming from abnormal electrical activity in the brain, are the defining characteristic of epilepsy, a chronic neurological condition. Because seizure features vary greatly, epilepsy is classified using two systems: by seizure type and by epilepsy syndromes. These classifications enable clinicians to describe seizure patterns and select suitable treatment strategies.I. Classification by Seizure Type1. Focal EpilepsyFocal epilepsy begins in one hemisphere of the brain.
01:22Myasthenia Gravis ll: Pathophysiology
The disease process of myasthenia gravis begins at the neuromuscular junction, where antibodies attack key proteins needed for muscle activation. This immune reaction weakens signal transmission, leading to the characteristic muscle fatigue and weakness that define the condition.Immune-Mediated DamageIn most individuals, antibodies target acetylcholine receptors (AChRs) on the postsynaptic membrane of muscle cells. By blocking acetylcholine binding, these antibodies prevent the nerve signal...
01:12Alterations in Muscle Tone ll
Alterations in muscle tone are common manifestations of neurological disorders and reflect dysfunction within different nervous system regions. Spasticity, paratonia, and dystonia represent distinct forms of hypertonia, each with unique mechanisms, clinical features, and diagnostic importance.CharacteristicsSpasticity happens from upper motor neuron lesions and is characterized by velocity-dependent resistance to passive movement. Clinical features include:Exaggerated deep tendon reflexesClonus...
01:11Alterations in Muscle Tone lll
Rigidity and myotonia are distinct abnormalities of muscle tone that affect resistance and relaxation during movement. Although both involve altered muscle contraction, they arise from different neurological and muscular mechanisms.CharacteristicsRigidity is characterized by uniform resistance to passive movement across the entire range, independent of speed, affecting flexors and extensors equally. It may appear as lead-pipe rigidity (smooth, constant resistance) or cogwheel rigidity...