Andersen-Tawil Syndrome

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Andersen-Tawil Syndrome is not the name you expected.

Disorder Subdivisions

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General Discussion

Andersen-Tawil syndrome is a rare genetic disorder characterized by episodes of muscle weakness and paralysis (periodic paralysis); abnormalities affecting the electrical system of the heart that can cause abnormal heart rhythms (arrhythmias); and a variety of distinctive facial and skeletal features. The specific symptoms and severity can vary greatly from one person to another, even among members of the same family. Some individuals will not develop all of the characteristic findings. Distinctive facial features may be so mild as to go unnoticed. In some cases, Andersen-Tawil syndrome is caused by mutations in the KCNJ2 gene; in other cases, the associated gene is unknown. The KCNJ2 gene mutation can occur randomly for unknown reasons (sporadically) or be inherited in an autosomal dominant manner.

Andersen-Tawil syndrome is sometimes referred to as long QT syndrome 7 because some individuals in early reports of the disorder had a prolonged QT interval, which is measured on an electrocardiogram and indicates that the heart muscle is taking longer than usual to recharge between beats. However, subsequent clinical reports have shown the QT interval is not prolonged or only mildly prolonged in most cases. Instead, the T-U wave pattern is markedly prolonged. In addition, unlike most forms of long QT syndrome, Andersen-Tawil syndrome is associated with symptoms in addition to disturbances of the electrical system of the heart. Although still sub-classified as a form of long QT syndrome, the disorder is recognized as separate from traditional long QT syndromes.
Andersen-Tawil syndrome can also be classified as a form of periodic paralysis, a group of rare neuromuscular disorders characterized by episodes of weakness or paralysis. The terms Andersen-Tawil syndrome type 1 or type 2 are also used in the medical literature. Type 1 refers to cases caused by a known KCNJ2 gene mutation; type 2 refers to cases without an identified KCNJ2 mutation.

Supporting Organizations

International Long QT Syndrome Registry

Heart Research Follow-up Program
Box 653
Rochester, NY 14642-8653
Tel: (585)276-0016
Fax: (585)273-5283

Muscular Dystrophy Association

3300 East Sunrise Drive
Tucson, AZ 85718-3208
Tel: (520)529-2000
Fax: (520)529-5300
Tel: (800)572-1717

NIH/National Heart, Lung and Blood Institute

P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223

NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424

Periodic Paralysis Association

155 West 68th Street
Apt. 1732
New York, NY 10023
Tel: (407)339-9499
Fax: (407)339-9499

Periodic Paralysis News Desk

2235 B 36th St. SW
Calgary, Alberta, T3E 2Z3
Tel: 4032447213

Ronnerweg 2
Nidau, 2560
Tel: 41794741535

SADS UK (Sudden Arrhythmic Death Syndrome)

Suite 6
Churchill House
West Horndon, CM13 3XD
United Kingdom
Tel: 1277811215

Sudden Arrhythmia Death Syndromes Foundation

508 E. South Temple
Suite 202
Salt Lake City, UT 84102
Tel: (801)531-0937
Fax: (801)531-0945
Tel: (800)786-7723

For a Complete Report

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Last Updated:  8/4/2015
Copyright  2015 National Organization for Rare Disorders, Inc.