Andersen-Tawil Syndrome is a genetic condition that causes periods of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and intellectual and developmental abnormalities. Other features can include low-set ears, widely spaced eyes, small mandible, fifth-digit clinodactyly, syndactyly, short stature, and scoliosis.
Speak to a genetic counselor or a medical geneticist if you have questions about Andersen-Tawil syndrome.
Andersen-Tawil Syndrome is known by several other names including:
Andersen Syndrome
Long QT Syndrome 7
Andersen Cardioysrhythmic periodic paralysis
The common abbreviation for Andersen-Tawil Syndrome is ATS.
The prevalence of Andersen-Tawil Syndrome is not known but about 100 people with the condition have been reported worldwide. Andersen-Tawil syndrome is diagnosed in fewer than 10% of individuals with primary periodic paralysis. The incidence of periodic paralysis is also unknown and estimated to be at most 1:100,000.
Those with Andersen-Tawil syndrome may have a small lower jaw (micrognathia), dental anomalies including crowded and missing teeth, lower than normal ears, eyes that are widely spaced, and fingers or toes that are unusually curved (clinodactyly). Some people with the condition may be shorter than normal and have an abnormally curved spine (scoliosis).
If you are interested in genetic testing for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
There are no known psychiatric conditions associated with Andersen-Tawil Syndrome.
Frequently Asked Questions About Andersen-tawil syndrome
Why might a child be tested for Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome may be suspected in a child with periods of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and physical features such ears that are lower than normal, eyes that are widely spaced, a small lower jaw (micrognathia), small hands and feet, a shorter than average height, or if they have at least one other family member with the condition.
Who else in my family should I test for Andersen-Tawil Syndrome?
The parents of a child with Andersen-Tawil Syndrome should have an evaluation by a cardiologist and/or neurologist. Parents should meet with a medical geneticist or genetic counselor to discuss genetic testing for Andersen-Tawil syndrome. About 50% (1 in 2) children will not have a parent with the condition. If parents do not have the condition, then the siblings of the child with Andersen-Tawil Syndrome have a low risk to have the condition.
A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
Where do I find other people with Andersen-Tawil Syndrome?
The Periodic Paralysis Association (www.periodicparalysis.org) has a discussion board that may be helpful in finding other people who experience the periods of muscle weakness (periodic paralysis) that are characteristic of Andersen-Tawil syndrome.
Also, Karen Carr Beihl runs a Facebook page and private Facebook group for those with Andersen tawil syndrome.
Andersen-Tawil syndrome is also listed on Patients Like Me.
What results from changes to the KCNJ2 gene?
Changes in the KCNJ2 gene causes changes in the structure and function of channels in the cell membrane that moves potassium into muscles. Our muscles that are responsible for movement and the muscles of the heart need this potassium to work correctly. When these muscles do not get the potassium that they need, it can cause periods of muscle weakness (periodic paralysis) and changes in heart rhythm (arrhythmia).
What is the usual abbreviation for Andersen-Tawil Syndrome?
The common abbreviation for Andersen-Tawil Syndrome is ATS.
What is the average life expectancy for someone with Andersen-Tawil Syndrome?
The average life expectancy for people with Andersen-Tawil Syndrome is not known, as the condition is so rare.
What is Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome is a genetic condition that causes periods of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and intellectual and developmental abnormalities. Other features can include low-set ears, widely spaced eyes, small mandible, fifth-digit clinodactyly, syndactyly, short stature, and scoliosis.
Speak to a genetic counselor or a medical geneticist if you have questions about Andersen-Tawil syndrome.
What health problems should I look for in Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome causes periods of muscle weakness (periodic paralysis) and changes in the heart rhythm (arrhythmia). Seizures during infancy (children between the age of 1 month and 1 year old) have been reported in a few people with this condition.
What gene cause Andersen-Tawil Syndrome?
Changes in the KCNJ2 gene have been shown to cause Andersen-Tawil Syndrome. Approximately 60% of individuals with Andersen-Tawil will have changes in this gene. However, some of the people with this condition do not have changes in this gene. In these people, the cause of Andersen-Tawil Syndrome is unknown. If you are interested in genetic testing for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
What does it mean to have inherited a "variant" or "variant of unknown significance" in the gene for Andersen-Tawil Syndrome?
Having a "variant of unknown significance" in the gene responsible for Andersen-Tawil Syndrome (KCNJ2) means that there was a change in this gene detected that currently doesn’t have enough research or evidence to say whether it can cause Andersen-Tawil Syndrome or if it is a non disease causing (benign) change. As more research is performed, the "variant" may be reclassified as disease causing (pathogenic) or benign.
Review uncertain genetic testing results with a genetic counselor or medical geneticist. medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
What are the main symptoms of Andersen-Tawil Syndrome?
Symptoms of Andersen-Tawil Syndrome include periods of muscle weakness (periodic paralysis) and changes in heart rhythm (arrhythmia). People with this condition may also have eyes that are widely spaced, ears that are lower than normal, dental problems including crowded or missing teeth, fingers or toes that are unusually curved (clinodactyly), small lower jaw (micrognathia), shorter than average height, and an overly curved spine (scoliosis).
What are the first steps after an initial diagnosis of Andersen-Tawil syndrome?
Depending upon the symptoms, there are a variety of doctors that someone with Andersen-Tawil syndrome may see. Your primary doctor may first suggest you see a cardiologist (heart doctor). A neurologist (nerve doctor) may also be seen. In addition, other specialists may be needed if there are spine problems (see a orthopedic doctor) or dental problems (see a dentist or oral surgeon).
Is there one or two characteristic "odd" or "unusual" symptom or clinical feature of Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome usually has three primary features including periods of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and unusual physical features.
Is there newborn testing for Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome is not currently available on newborn screening. However, children with symptoms of Andersen-Tawil Syndrome should be evaluated by a doctor who specializes in the heart (cardiologist) and a doctor who specializes in the nervous system (neurologist) If you are interested in genetic testing for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
Is there more than one test for Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome is caused by gene changes in the KCNJ2 gene. Changes in this gene can be found by looking at this gene in a single test, or by looking at this gene and other genes of interest on one panel.
If you are interested in genetic testing for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
Is there clinical research going on for Andersen-Tawil Syndrome?
As of June 2019, there were not clinical trials for treatments for Andersen-Tawil. However, there was a study looking to understand it better. Clinicaltrials.gov has listings of clinical trials in the United States. Check their website for the most up to date information.
Is there a treatment(s) for Andersen-Tawil Syndrome?
Treatment for Andersen-Tawil syndrome may include taking potassium supplements during periods of muscle weakness (periodic paralysis) until the symptoms go away if the potassium levels are found to be low during these periods. If the amount of potassium during these periods is found to be high, eating foods high in carbohydrates or mild exercise may shorten the attack.
Speak with your physician or a medical geneticist regarding treatment for Andersen-Tawil syndrome. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website.
If this is a predisposition gene, what are the chances I will get Andersen-Tawil Syndrome?
Between 80-94% of people with changes in the KCNJ2 gene will develop symptoms of Andersen-Tawil Syndrome.
If my child has Andersen-Tawil Syndrome, what specialist doctors should they see?
Following a diagnosis, it is recommended that a cardiologist and neurologist follow a child with Andersen-Tawil Syndrome.
If my child has Andersen-Tawil Syndrome, what should their doctor know about managing the disease?
Management of people with Andersen-Tawil Syndrome requires both the knowledge of a neurologist familiar with the treatment of periods of muscle weakness (periodic paralysis) and a cardiologist familiar with the treatment of changes in heart rhythm (arrhythmia).
If I have Andersen-Tawil Syndrome, what is the chance that I will have a child with the condition?
If you have Andersen-Tawil Syndrome, there is a 50% (1 in 2) chance that you will have a child with the condition.
Speak to a genetic counselor or medical geneticist to discuss recurrence risks in your family and available testing options. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
If I have Andersen-Tawil Syndrome, is it safe for me to get pregnant?
Because Andersen-Tawil Syndrome is rare there is limited information about women who have this condition who get pregnant. This lack of research makes recommendations for pregnancy management difficult. Similar to those with long QT syndrome, being watched carefully and understanding that they may have an increased risk seems to be a reasonable recommendation. Speak with your physician prior to considering a pregnancy. Your physician may refer to to a maternal fetal medicine physician who are physicians that manage high risk pregnancies
If I have a negative genetic test result for the KCNJ2 gene, does that mean I do not have Andersen-Tawil syndrome?
As of June 2019, the diagnosis of Andersen-Tawil is based on the symptoms the person has. Genetic testing is useful to help screen other family members who might be at risk. However, if you do not have a harmful gene change (mutation) in the KCNJ2 gene, you still have Andersen-Tawil syndrome if you have the symptoms. Scientists are still learning about genes that may cause Andersen-Tawil and periodic paralysis. If you have had genetic testing for the KCNJ2 gene and the results were negative, speak with your doctor or a genetic professional regarding other genes that might be tested. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
I already have one child with Andersen-Tawil Syndrome, what is the chance that I will have a second child with the condition?
Andersen-Tawil Syndrome is inherited in an autosomal dominant pattern, which means that having a change in one copy of a KCNJ2 gene change is enough to cause symptoms of the condition. If a parent of a child with Andersen-Tawil syndrome is also found to have a change in the KCNJ2 gene, then each child of that parent will have a 50% chance of receiving that copy of the gene change and having symptoms of Andersen-Tawil. If the parents do not have symptoms or a change in the gene was not found, then the chance of having another child with Andersen-Tawil Syndrome is very low.
Speak to a genetic counselor or a medical geneticist regarding recurrence risks in your family.
How many people with the gene change associated with Andersen-Tawil Syndrome develop symptoms?
Up to 20% (1 in 5) people who have a change in a gene associated with Andersen-Tawil Syndrome (KCNJ2) will not have symptoms.
How is Andersen-Tawil Syndrome inherited?
Andersen-Tawil Syndrome is inherited in an autosomal dominant pattern meaning that one change in the KCNJ2 gene is enough to cause symptoms of this condition. About 50% of people with Andersen-Tawil Syndrome have a parent with the condition. The other 50% of people have the condition as a result of a new (de novo) change in the gene.
If you are interested in genetic testing for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
How do I give money to help research in Andersen-Tawil Syndrome?
Donations are accepted by the Periodic Paralysis Foundation (www.periodicparalysis.org) to further research and provide education to individuals and families with periods of muscle weakness (periodic paralysis).
How do I find clinical research in Andersen-Tawil Syndrome?
Clinical research trials can be found by searching for ‘Andersen-Tawil Syndrome’ on www.clinicaltrials.gov.
How do I find a center of excellence in Andersen-Tawil Syndrome?
These centers have a special interest in periodic paralysis (periods of muscle weakness), a symptom characteristic of Andersen-Tawil Syndrome.
How common is Andersen-Tawil Syndrome?
The prevalence of Andersen-Tawil Syndrome is not known but about 100 people with the condition have been reported worldwide. Andersen-Tawil syndrome is diagnosed in fewer than 10% of individuals with primary periodic paralysis. The incidence of periodic paralysis is also unknown and estimated to be at most 1:100,000.
How are children tested for Andersen-Tawil Syndrome?
Children who have symptoms related to Andersen-Tawil Syndrome will generally have an evaluation by a doctor who specializes in the heart (cardiologist) and a doctor who specializes in nerves (neurologist). These doctors will want to measure how much potassium the person when they feel normal and when they are having a period of muscle weakness (periodic paralysis). A test that looks at the rhythm of the heart may be performed (ECG) in addition to wearing a device that monitors the heart (Holter monitor) for 24 hours. If there are concerns for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
Does anything make Andersen-Tawil Syndrome worse?
People with Andersen-Tawil Syndrome should avoid medications that are known to prolong their QT intervals. (The QT interval is the time it takes the heart to contract and relax while it is pumping blood.) They should also avoid inhalers often used to treat asthma (salbutamol inhalers). Thiazide and other potassium-wasting diuretics may provoke drug-induced hypokalemia (low potassium level) and could affect the QT interval. Review your medications with your physician if you have been diagnosed with Andersen-Tawil syndrome.
Can the frequency, length, and severity of the periods of muscle weakness vary between different people with Andersen-Tawil Syndrome?
The frequency, length, and severity of the periods of muscle weakness can vary between different people with Andersen-Tawil Syndrome. Periods of weakness may also vary between family members who also have the condition. Permanent weakness may also be seen.
Are there psychiatric conditions associated with Andersen-Tawil Syndrome?
There are no known psychiatric conditions associated with Andersen-Tawil Syndrome.
Are there other organ specific treatments/symptom specific concomitant treatments for Andersen-Tawil Syndrome?
People with Andersen-Tawil Syndrome who faint when their heart beat speeds up may have an implanted cardioverter-defibrillator (ICD) placed under their skin to monitor their heart rate. If the device senses a change in the heart rhythm, it will give your heart a small electrical shock to bring the rhythm back to normal.
Speak with your physician, a cardiologist (heart doctor), or a medical geneticist regarding treatment for Andersen-Tawil syndrome. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website.
Are there other names for Andersen-Tawil Syndrome?
Andersen-Tawil Syndrome is known by several other names including:
Are there learning problems associated with Andersen-Tawil Syndrome?
Mild learning problems have been described in Andersen-Tawil Syndrome. Even though IQ scores between a affected and unaffected siblings were similar, the affected siblings tend to have problems with memory/reasoning/problem solving (executive function) and their ability to identify patterns/apply this information to solve problems (abstract reasoning).
Are there good support groups for Andersen-Tawil Syndrome?
Periodic Paralysis Association www.periodicparalysis.org
Periodic Paralysis International www.hkpp.org
Sudden Arrhythmia Death Syndromes Foundation www.sads.org
Andersen tawil syndrome Facebook Page https://www.facebook.com/AndersenTawilSyndrome
Patients Like Me
Are there earlier onset, later onset, or variant forms of Andersen-Tawil Syndrome?
Symptoms of Andersen-Tawil Syndrome usually begin before the person turns 20 years old and may include changes in heart rhythm (arrhythmia) or periods of weakness that occur randomly following periods of rest or following resting after exercising.
Are there characteristic physical features associated with Andersen-Tawil Syndrome?
Those with Andersen-Tawil syndrome may have a small lower jaw (micrognathia), dental anomalies including crowded and missing teeth, lower than normal ears, eyes that are widely spaced, and fingers or toes that are unusually curved (clinodactyly). Some people with the condition may be shorter than normal and have an abnormally curved spine (scoliosis).
If you are interested in genetic testing for Andersen-Tawil syndrome, speak with a medical geneticist or genetic counselor to help you obtain testing. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.
Are there any other diseases that look a lot like Andersen-Tawil Syndrome?
Hypokalemic (low potassium levels) periodic paralysis may look very similar to Andersen-Tawil Syndrome but it lacks the physical features and the periods of muscle weakness generally do not affect the muscles of the heart. Thyrotoxic periodic paralysis is similar to hypokalemic periodic paralysis but only occurs in people with an overactive thyroid gland. There are also a group of syndromes called long QT that cause the heart to take longer to recharge between beats causing changes in heart rhythm (arrhythmia).
