Overview
Andersen-Tawil syndrome (ATS), also known as Andersen syndrome or Long QT syndrome type 7 (LQT7), is a rare genetic condition that affects the heart, muscles, and physical development. It belongs to a group of diseases called channelopathies, meaning it is caused by a problem with tiny channels in cells that control the flow of electrically charged particles called ions. In ATS, a faulty potassium channel disrupts normal electrical signals in both heart muscle and skeletal muscle. The condition causes three main groups of problems that often appear together: episodes of muscle weakness or paralysis (called periodic paralysis), an abnormal heart rhythm that can be seen on an ECG (called long QT syndrome with a distinctive pattern), and certain physical features present from birth such as low-set ears, a small jaw, widely spaced eyes, curved fingers, and short stature. Not every person with ATS has all three features, which can make diagnosis tricky. Treatment focuses on managing symptoms. Heart rhythm problems may be treated with medications or, in some cases, a device called an implantable cardioverter-defibrillator (ICD). Muscle weakness episodes can sometimes be reduced by avoiding triggers like fasting, cold, or heavy exercise, and with certain medications. There is currently no cure, but with careful monitoring and management, many people with ATS can lead meaningful lives.
Also known as:
Key symptoms:
Episodes of sudden muscle weakness or temporary paralysisIrregular or abnormal heart rhythm (arrhythmia)Prolonged QT interval seen on heart tracing (ECG)Low levels of potassium in the blood (hypokalemia) during weakness episodesSmall or underdeveloped lower jaw (micrognathia)Low-set or abnormally shaped earsWidely spaced eyes (hypertelorism)Short statureCurved or bent fingers (clinodactyly)Fused or extra toes or fingers (syndactyly or polydactyly)Scoliosis (curved spine)Palpitations or awareness of heartbeatFainting or near-fainting spellsFatigue and exercise intoleranceMild learning or behavioral difficulties in some individuals
Clinical phenotype terms (50)— hover any for plain English
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Variable
Can begin at different ages, from infancy through adulthood
Treatments
No FDA-approved treatments are currently listed for Andersen-Tawil syndrome.
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Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Andersen-Tawil syndrome.
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Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.Which of the three main features of Andersen-Tawil syndrome does my child or I have, and how severe are they?,What is my personal risk of a dangerous heart arrhythmia, and do I need an ICD?,What medications, foods, or activities should I avoid to reduce the risk of weakness episodes or heart problems?,Should my family members be tested for the KCNJ2 gene mutation?,How often do I need heart monitoring (ECG or Holter monitor), and what should I watch for at home?,Are there any clinical trials or research studies I could participate in?,What should I tell emergency room doctors if I have a crisis — is there a medical alert card or letter I should carry?
Common questions about Andersen-Tawil syndrome
What is Andersen-Tawil syndrome?
Andersen-Tawil syndrome (ATS), also known as Andersen syndrome or Long QT syndrome type 7 (LQT7), is a rare genetic condition that affects the heart, muscles, and physical development. It belongs to a group of diseases called channelopathies, meaning it is caused by a problem with tiny channels in cells that control the flow of electrically charged particles called ions. In ATS, a faulty potassium channel disrupts normal electrical signals in both heart muscle and skeletal muscle. The condition causes three main groups of problems that often appear together: episodes of muscle weakness or par
How is Andersen-Tawil syndrome inherited?
Andersen-Tawil syndrome follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
Which specialists treat Andersen-Tawil syndrome?
3 specialists and care centers treating Andersen-Tawil syndrome are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.