Decoding the Mystery: Acquired Susceptibility to Long QT Syndrome 1
Medically reviewed by Brandon Colby, MD, last reviewed
Short answer: Acquired long QT syndrome, including acquired susceptibility to long QT syndrome 1, is a form of long QT syndrome that develops later in life because of external factors, such as certain medications or electrolyte imbalances. Some people are more susceptible because of their genes, and genetic testing can help identify who may be at risk.
Understanding Acquired Susceptibility to Long QT Syndrome 1
Long QT Syndrome (LQTS) is a disorder that affects the electrical system of the heart, causing irregular and potentially life-threatening heart rhythms. Acquired susceptibility to Long QT Syndrome 1 (aLQTS1) refers to a specific subtype of LQTS, where individuals develop the condition later in life due to external factors, such as certain medications or electrolyte imbalances. This acquired form of LQTS can be difficult to diagnose, as symptoms may be subtle or absent, and the risk factors are not well understood.
Recent studies have shed light on the genetic factors that may contribute to a person's susceptibility to aLQTS1. The KCNQ1 gene provides instructions for making part of a potassium channel that helps the heart reset electrically between beats. A study of patients with acquired long QT syndrome identified disease-causing variants in KCNQ1 and other long QT–associated genes, suggesting that an underlying genetic predisposition can contribute to the condition. A separate study found that rare susceptibility variants in CYP genes, which are involved in drug metabolism, could be important pharmacogenomic risk markers for this condition. Additionally, another article discusses how the separation of neuronal nitric oxide synthase from its adaptor protein can cause arrhythmogenic trigger-substrate interactions in LQTS.
Diagnosing Acquired Susceptibility to Long QT Syndrome 1
Diagnosing aLQTS1 can be challenging, as symptoms may be subtle or absent. However, genetic testing can be a valuable tool in identifying individuals at risk for this condition. A white paper examines the current classification and reporting of potentially proarrhythmic common genetic variants in LQTS genetic testing. By understanding these genetic factors, healthcare providers can better identify individuals who may be at risk for aLQTS1 and take appropriate preventive measures.
Uses of Genetic Testing for Acquired Susceptibility to Long QT Syndrome 1
Genetic testing for aLQTS1 can be helpful in several ways:
- Risk Assessment: Identifying individuals with genetic variants that increase their susceptibility to aLQTS1 can help healthcare providers assess their overall risk for developing the condition.
- Preventive Measures: For those identified as being at increased risk for aLQTS1, healthcare providers can recommend lifestyle modifications, medication adjustments, or other interventions to help prevent the onset of the condition.
- Family Screening: Genetic testing can also be used to screen family members of individuals diagnosed with aLQTS1, as they may be at an increased risk for developing the condition as well.
- Research: By studying the genetic factors associated with aLQTS1, researchers can gain a better understanding of the condition and potentially develop new treatments or preventive measures.
Advancements in Genetic Research for Long QT Syndrome
As our understanding of the genetic factors associated with aLQTS1 continues to grow, so does the potential for improved diagnosis and treatment. A recent transethnic genome-wide association study provided insights into the genetic architecture and heritability of LQTS, which could help guide future research and clinical applications.
While there is still much to learn about acquired susceptibility to Long QT Syndrome 1, the advancements in genetic research and testing are promising steps towards better understanding, diagnosing, and managing this complex condition.
Related Long QT Syndrome Articles
- Congenital Long QT Syndrome: the inherited form, and the role of genetic testing.
- KCNQ1-Related Disorders: long QT and heart rhythm conditions linked to the KCNQ1 gene.
- Long QT Syndrome 1, Recessive: KCNQ1 and diagnosis.
- Long QT Syndrome 2: Acquired Susceptibility: what genetic testing shows.
- Long QT Syndrome 3: Acquired Susceptibility: SCN5A, ECG findings and testing.
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Frequently Asked Questions About Acquired Susceptibility to Long QT Syndrome 1
What is acquired susceptibility to long QT syndrome 1?
Long QT syndrome (LQTS) affects the electrical system of the heart and can cause irregular and potentially life threatening heart rhythms. Acquired susceptibility to long QT syndrome 1 describes a form where the condition develops later in life because of external factors, such as certain medications or electrolyte imbalances.
What causes acquired long QT syndrome?
External factors such as certain medications and electrolyte imbalances can bring it on. Research also shows that some people are more susceptible because of their genes. A 2022 study found that rare variants in genes involved in drug metabolism, including CYP genes, and in long QT genes may act as pharmacogenomic risk markers for acquired long QT syndrome.
What are the symptoms?
Symptoms may be subtle or absent, which is one reason the condition can be difficult to diagnose. Talk to your doctor if you have concerns about your heart rhythm.
How is acquired susceptibility to long QT syndrome 1 diagnosed?
Diagnosis can be challenging because symptoms may be subtle or absent. Genetic testing can help identify people who may be at risk. A 2018 white paper in Circulation examined how potentially proarrhythmic common genetic variants should be classified and reported in long QT syndrome genetic testing, which helps healthcare providers interpret genetic results. Your doctor or a cardiologist can advise on the right evaluation for you.
How can genetic testing help?
Genetic testing can help assess risk, guide preventive steps such as medication adjustments or lifestyle changes with your healthcare provider, and support research. It can also be used to screen family members of someone who has been diagnosed, since they may be at increased risk. A genetic result shows susceptibility. It does not mean you will definitely develop the condition.
Does Sequencing test for this condition?
Whole genome sequencing reads 100% of your DNA, which includes the genes involved in heart rhythm and drug metabolism discussed in this article. Sequencing's Kit Bundles include Next Gen Disease Screening, which analyzes your genome for more than 15,000 conditions. You can also upload DNA data from another test for free and search it in Genome Explorer. Results describe variants, not a diagnosis.
What should I do if I take a medication that can affect heart rhythm?
Do not stop or change any medication on your own. Talk with your doctor or pharmacist about your risk and your options.
Where can I find support or a specialist?
The Foundation For Inherited Arrythmias (FIA) supports people and families affected by inherited heart rhythm conditions and has a tool to find a doctor. GeneReviews also has an expert written overview of long QT syndrome. Both are listed in the resources below.
Resources
These organizations and resources are provided for education and support. They are not endorsements or medical advice.
- Foundation For Inherited Arrythmias (FIA) (United States): a patient and family organization for inherited heart rhythm conditions.
- FIA: Find a doctor: the organization's directory for finding a specialist.
- FIA: Scientific advisors: the medical and scientific advisors who guide the organization.
- GeneReviews: Long QT Syndrome Overview (NCBI Bookshelf): an expert written clinical overview of long QT syndrome and its genetics.
References
- Gray B, Baruteau A, Antolin A, et al. Rare variation in drug metabolism and long QT genes and the genetic susceptibility to acquired long QT syndrome. Circ Genom Precis Med. 2022;15(1):e003391. doi:10.1161/CIRCGEN.121.003391
- Tieu A, Akar F. 'Social distancing' of the neuronal nitric oxide synthase from its adaptor protein causes arrhythmogenic trigger-substrate interactions in long QT syndrome. Cardiovasc Res. 2021;117(2):338-340. doi:10.1093/cvr/cvaa179
- Giudicessi JR, Roden DM, Wilde AAM, Ackerman MJ. Classification and reporting of potentially proarrhythmic common genetic variation in long QT syndrome genetic testing. Circulation. 2018;137(6):619-630. doi:10.1161/CIRCULATIONAHA.117.030142
- Lahrouchi N, Tadros R, Crotti L, et al. Transethnic genome-wide association study provides insights in the genetic architecture and heritability of long QT syndrome. Circulation. 2020;142(4):324-338. doi:10.1161/CIRCULATIONAHA.120.045956
- Itoh H, Crotti L, Aiba T, et al. The genetics underlying acquired long QT syndrome: impact for genetic screening. Eur Heart J. 2016;37(18):1456-1464. doi:10.1093/eurheartj/ehv695
This article is for education and is not a substitute for professional medical advice, diagnosis, or treatment. Talk to a qualified healthcare provider about your own health.