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Andersen-Tawil syndrome

Other Names for this Disease
  • Andersen cardiodysrhythmic periodic paralysis
  • Andersen syndrome
  • Long QT syndrome 7
  • LQT7
  • Periodic paralysis, potassium-sensitive cardiodysrhythmic type
More Names
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What is Andersen-Tawil syndrome?

What are the signs and symptoms of Andersen-Tawil syndrome?

Is genetic testing available for Andersen-Tawil syndrome?

How is Andersen-Tawil syndrome diagnosed?

What is Andersen-Tawil syndrome?

Andersen-Tawil syndrome is a type of long QT syndrome and is also considered a rare form of periodic paralysis. It causes episodes of muscle weakness, changes in heart rhythm (arrhythmia), and developmental abnormalities. Physical abnormalities associated with this condition typically affect the head, face, and limbs. There are two different types of Andersen-Tawil syndrome. Type 1 is caused by changes in the KCNJ2 gene, while the cause of type 2 is not yet known. Andersen-Tawil syndrome is inherited in an autosomal dominant pattern.[1]
Last updated: 10/11/2011

What are the signs and symptoms of Andersen-Tawil syndrome?

Anderson-Tawil syndrome causes episodes of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and developmental abnormalities. The most common changes affecting the heart are ventricular arrhythmia, which is a disruption in the rhythm of the heart's lower chambers, and long QT syndrome. Long QT syndrome is a heart condition that causes the heart muscle to take longer than usual to recharge between beats. If untreated, the irregular heartbeats can lead to discomfort, fainting, or cardiac arrest.[1]

Physical abnormalities associated with Andersen-Tawil syndrome typically affect the head, face, and limbs. These features often include a very small lower jaw (micrognathia), dental abnormalities, low-set ears, widely spaced eyes, and unusual curving of the fingers or toes (clinodactyly). Some affected people also have short stature and an abnormal curvature of the spine (scoliosis).[1]
Last updated: 10/11/2011

Is genetic testing available for Andersen-Tawil syndrome?

Yes, genetic testing is available for Andersen-Tawil syndrome type 1, which accounts for about 60% of cases of this condition. GeneTests lists the names of laboratories that are performing genetic testing for Andersen-Tawil syndrome type 1. To view the contact information for the clinical laboratories conducting testing, click here.

Please note:  Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional. 
Last updated: 10/11/2011

How is Andersen-Tawil syndrome diagnosed?

The diagnosis of Andersen-Tawil syndrome might be suspected in individuals with either:[2]

1. Two of the following three criteria:

  • Periodic paralysis
  • Symptomatic cardiac arrhythmias or evidence of enlarged U-waves, ventricular ectopy, or a prolonged QTc or QUc interval on electrocardiogram (ECG) 
  • Characteristic facial features, dental abnormalities, small hands and feet, and at least two of the following:
    • Low-set ears
    • Ocular hypertelorism
    • Small mandible
    • Fifth-digit clinodactyly
    • Syndactyly


2. One of the above three criteria in addition to at least one other family member who meets two of the three criteria.

The presence of a mutation in the KCNJ2 gene confirms the diagnosis of Andersen-Tawil syndrome type 1.[2]
Last updated: 10/11/2011

  1. Andersen-Tawil syndrome. Genetics Home Reference. April 2006; Accessed 10/11/2011.
  2. Tawil R & Venance SL. Andersen-Tawil Syndrome. GeneReviews. May 2010; Accessed 10/11/2011.