Andersen-tawil syndrome
Diagnosis and Testing
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.
References
More Diagnosis and Testing Content
How are children tested for Andersen-Tawil Syndrome?
If I have Andersen-Tawil Syndrome, is it safe for me to get pregnant?
If I have Andersen-Tawil Syndrome, what is the chance that I will have a child with the condition?
How do I get tested for Andersen-Tawil Syndrome?
Is there newborn testing for Andersen-Tawil Syndrome?
Is there more than one test for Andersen-Tawil Syndrome?
Who else in my family should I test for Andersen-Tawil Syndrome?
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.
References
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.
References
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
References
- http://www.ncbi.nlm.nih.gov/books/NBK1264/
- Subbiah RN, Gula LJ, Skanes AC, Krahn AD. Andersen-Tawil Syndrome: management challenges during pregnancy, labor, and delivery. J Cardiovasc Electrophysiol. 2008 Sep;19(9):987-9. doi: 10.1111/j.1540-8167.2008.01216.x. Epub 2008 Jun 28. PubMed PMID: 18554214.
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.
References
How do I get tested for Andersen-Tawil Syndrome?
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.
References
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.
References
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.