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Andersen-Tawil syndrome

Reviewed April 2006

What is Andersen-Tawil syndrome?

Anderson-Tawil syndrome is a disorder that 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 (cardiac) muscle to take longer than usual to recharge between beats. If untreated, the irregular heartbeats can lead to discomfort, fainting (syncope), or cardiac arrest.

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).

Two types of Andersen-Tawil syndrome are distinguished by their genetic causes. Type 1, which accounts for about 60 percent of all cases of the disorder, is caused by mutations in the KCNJ2 gene. The remaining 40 percent of cases are designated as type 2; the cause of these cases is unknown.

How common is Andersen-Tawil syndrome?

Andersen-Tawil syndrome is a rare genetic disorder; its incidence is unknown. About 100 people with this condition have been reported worldwide.

What genes are related to Andersen-Tawil syndrome?

Mutations in the KCNJ2 gene cause Andersen-Tawil syndrome.

The KCNJ2 gene provides instructions for making a protein that forms a channel across cell membranes. This channel transports positively charged atoms (ions) of potassium into muscle cells. The movement of potassium ions through these channels is critical for maintaining the normal functions of muscles used for movement (skeletal muscles) and cardiac muscle. Mutations in the KCNJ2 gene alter the usual structure and function of potassium channels or prevent the channels from being inserted correctly into the cell membrane. Many mutations prevent a molecule called PIP2 from binding to the channels and effectively regulating their activity. These changes disrupt the flow of potassium ions in skeletal and cardiac muscle, leading to the periodic paralysis and irregular heart rhythm characteristic of Andersen-Tawil syndrome.

Researchers have not determined the role of the KCNJ2 gene in bone development, and it is not known how mutations in the gene lead to the developmental abnormalities often found in Andersen-Tawil syndrome.

How do people inherit Andersen-Tawil syndrome?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, a person with Andersen-Tawil syndrome inherits the mutation from one affected parent. Other cases result from new mutations in the KCNJ2 gene. These cases occur in people with no history of the disorder in their family.

Where can I find information about treatment for Andersen-Tawil syndrome?

You may find information on treatment or management of Andersen-Tawil syndrome or some of its symptoms in the links below, particularly the links for Gene Reviews, Educational resources, and Patient support.

Where can I find additional information about Andersen-Tawil syndrome?

You may find the following resources about Andersen-Tawil syndrome helpful. These materials are written for the general public.

  • MedlinePlus - Health information
    • Health Topic: Arrhythmia (http://www.nlm.nih.gov/medlineplus/arrhythmia.html)
    • Health Topic: Congenital Heart Defects (http://www.nlm.nih.gov/medlineplus/congenitalheartdefects.html)
  • Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases (http://rarediseases.info.nih.gov/GARD/Disease.aspx?PageID=4&DiseaseID=9453)
  • Additional NIH Resources - National Institutes of Health
    • National Center for Biotechnology Information: Genes and Disease (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=gnd.section.142)
    • National Heart, Lung, and Blood Institute (http://www.nhlbi.nih.gov/health/dci/Diseases/qt/qt_whatis.html)
  • Educational resources - Information pages
    • American Heart Association (http://www.americanheart.org/presenter.jhtml?identifier=993)
    • Centre for Genetics Education (Australia) (http://www.genetics.com.au/pdf/factsheets/fs55.pdf)
    • Cleveland Clinic (http://www.clevelandclinic.org/heartcenter/pub/guide/disease/electric/longqtsyndrome.htm?index=10494)
    • Heart Rhythm Society: Long QT Syndrome (http://www.hrspatients.org/patients/heart_disorders/long_qt_syndrome.asp)
    • KidsHealth from the Nemours Foundation (http://kidshealth.org/teen/diseases_conditions/heart/arrhythmias.html)
    • Mayo Clinic (http://www.mayoclinic.org/long-qt-syndrome/)
    • Merck Manual of Medical Information, Second Home Edition (http://www.merck.com/mmhe/sec23/ch266/ch266i.html)
    • Mount Sinai School of Medicine (http://www.mssm.edu/cvi/arrhythmia.shtml)
    • New York Online Access to Health (http://www.noah-health.org/en/blood/disease/specific/arrhythmias.html)
    • Orphanet (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=37553)
  • Patient support - For patients and families
    • Cardiac Arrythmias Research and Education (CARE) Foundation (http://www.longqt.org/)
    • Congenital Heart Information Network (http://tchin.org/)
    • Muscular Dystrophy Association (http://www.mda.org/disease/pp.html)
    • QTsyndrome.ch (European Long QT Syndrome Information Center) (http://www.qtsyndrome.ch/)
    • Resource list from the University of Kansas Medical Center (http://www.kumc.edu/gec/support/conghart.html)
    • Sudden Arrhythmia Death Syndromes (SADS) Foundation (http://www.sads.org/)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

  • Gene Reviews - Clinical summary (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=acpp)
  • Gene Tests - DNA tests ordered by healthcare professionals (http://www.genetests.org/query?testid=116502)
  • ClinicalTrials.gov - Linking patients to medical research (http://clinicaltrials.gov/search/condition=%22Andersen-Tawil+syndrome%22+OR+%22Long+QT+Syndrome%22)
  • PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=PubMed&term=((andersen-tawil+syndrome[TI])+OR+(andersen+syndrome[TI])+OR+(andersen's+syndrome[TI]))+OR+((long+qt+syndrome+7[TI])+OR+(lqt7[TI]))+AND+english[la]+AND+human[mh]&orig_db=PubMed&filters=ON&pmfilter_EDatLimit=3600+Days)
  • OMIM - Genetic disorder catalog (http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=170390)

What other names do people use for Andersen-Tawil syndrome?

  • Andersen cardiodysrhythmic periodic paralysis
  • Andersen syndrome
  • ATS
  • Long QT syndrome 7
  • LQT7
  • Periodic paralysis, potassium-sensitive cardiodysrhythmic type

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about Andersen-Tawil syndrome?

  • See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
  • Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).
  • Submit your question to Ask the Geneticist (http://www.askthegen.org/).

What glossary definitions help with understanding Andersen-Tawil syndrome?

arrhythmia ; atom ; autosomal ; autosomal dominant ; cardiac ; cardiac arrest ; cell ; cell membrane ; channel ; clinodactyly ; fainting ; gene ; incidence ; ions ; long QT syndrome ; micrognathia ; molecule ; mutation ; new mutation ; potassium ; protein ; scoliosis ; short stature ; skeletal muscle ; stature ; syncope ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).

References
  • Bendahhou S, Fournier E, Sternberg D, Bassez G, Furby A, Sereni C, Donaldson MR, Larroque MM, Fontaine B, Barhanin J. In vivo and in vitro functional characterization of Andersen's syndrome mutations. J Physiol. 2005 Jun 15;565(Pt 3):731-41. Epub 2005 Apr 14. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=15831539)
  • Davies NP, Imbrici P, Fialho D, Herd C, Bilsland LG, Weber A, Mueller R, Hilton-Jones D, Ealing J, Boothman BR, Giunti P, Parsons LM, Thomas M, Manzur AY, Jurkat-Rott K, Lehmann-Horn F, Chinnery PF, Rose M, Kullmann DM, Hanna MG. Andersen-Tawil syndrome: new potassium channel mutations and possible phenotypic variation. Neurology. 2005 Oct 11;65(7):1083-9. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=16217063)
  • Donaldson MR, Jensen JL, Tristani-Firouzi M, Tawil R, Bendahhou S, Suarez WA, Cobo AM, Poza JJ, Behr E, Wagstaff J, Szepetowski P, Pereira S, Mozaffar T, Escolar DM, Fu YH, Ptacek LJ. PIP2 binding residues of Kir2.1 are common targets of mutations causing Andersen syndrome. Neurology. 2003 Jun 10;60(11):1811-6. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=12796536)
  • Donaldson MR, Yoon G, Fu YH, Ptacek LJ. Andersen-Tawil syndrome: a model of clinical variability, pleiotropy, and genetic heterogeneity. Ann Med. 2004;36 Suppl 1:92-7. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=15176430)
  • Gene Review: Andersen-Tawil Syndrome (http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=acpp)
  • Modell SM, Lehmann MH. The long QT syndrome family of cardiac ion channelopathies: A HuGE review. Genet Med. 2006 Mar;8(3):143-55. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=16540748)
  • Plaster NM, Tawil R, Tristani-Firouzi M, Canun S, Bendahhou S, Tsunoda A, Donaldson MR, Iannaccone ST, Brunt E, Barohn R, Clark J, Deymeer F, George AL Jr, Fish FA, Hahn A, Nitu A, Ozdemir C, Serdaroglu P, Subramony SH, Wolfe G, Fu YH, Ptacek LJ. Mutations in Kir2.1 cause the developmental and episodic electrical phenotypes of Andersen's syndrome. Cell. 2001 May 18;105(4):511-9. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=11371347)
  • Tristani-Firouzi M, Jensen JL, Donaldson MR, Sansone V, Meola G, Hahn A, Bendahhou S, Kwiecinski H, Fidzianska A, Plaster N, Fu YH, Ptacek LJ, Tawil R. Functional and clinical characterization of KCNJ2 mutations associated with LQT7 (Andersen syndrome). J Clin Invest. 2002 Aug;110(3):381-8. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=12163457)
  • Venance SL, Cannon SC, Fialho D, Fontaine B, Hanna MG, Ptacek LJ, Tristani-Firouzi M, Tawil R, Griggs RC; CINCH investigators. The primary periodic paralyses: diagnosis, pathogenesis and treatment. Brain. 2006 Jan;129(Pt 1):8-17. Epub 2005 Sep 29. Review. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&dopt=Abstract&list_uids=16195244)

 

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: April 2006
Published: May 4, 2009