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Cardiodysrhythmic potassium-sensitive periodic paralysis

Synonym(s) Andersen cardiodysrhythmic periodic paralysis
Andersen syndrome
Andersen-Tawil syndrome
Long QT syndrome type 7
Prevalence Unknown
Inheritance Autosomal dominant
Age of onset Childhood
  • G72.3
MeSH -
MedDRA -


Disease definition

Andersen's syndrome (AS) is a rare disorder characterized by periodic muscle paralysis, prolongation of the QT interval with a variety of ventricular arrhythmias (leading to predisposition to sudden cardiac death) and characteristic physical features: short stature, scoliosis, low-set ears, hypertelorism, broad nasal root, micrognathia, clinodactyly, brachydactyly and syndactyly.


Mutations in KCNJ2, which encodes the alpha subunit of the potassium channel Kir2.1, account for approximately 60% of cases.

Genetic counseling

AS is inherited as an autosomal dominant trait although sporadic cases have been reported. Penetrance is extremely variable.

Management and treatment

Treatment depends on the individual and their reaction to potassium. Patients with severe arrhythmias may require a pacemaker.

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Detailed information

Clinical practice guidelines
Clinical genetics review
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