Familial Atrial Fibrillation News and Articles
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What is familial atrial fibrillation?
Familial atrial fibrillation is an inherited condition that disrupts the heart's normal rhythm. This condition is characterized by uncoordinated electrical activity in the heart's upper chambers (the atria), which causes the heartbeat to become fast and irregular. If untreated, this abnormal heart rhythm can lead to dizziness, chest pain, a sensation of fluttering or pounding in the chest (palpitations), shortness of breath, or fainting (syncope). Atrial fibrillation also increases the risk of stroke and sudden death. Complications of familial atrial fibrillation can occur at any age, although some people with this heart condition never experience any health problems associated with the disorder.
How common is familial atrial fibrillation?
Atrial fibrillation is the most common type of sustained abnormal heart rhythm (arrhythmia), affecting more than 3 million people in the United States. The risk of developing this irregular heart rhythm increases with age. The incidence of the familial form of atrial fibrillation is unknown; however, recent studies suggest that up to 30 percent of all people with atrial fibrillation may have a history of the condition in their family.
What genes are related to familial atrial fibrillation?
Mutations in the KCNQ1 gene cause familial atrial fibrillation.
The KCNE2 and KCNJ2 genes are associated with familial atrial fibrillation.
A small percentage of all cases of familial atrial fibrillation are associated with changes in the KCNE2, KCNJ2, and KCNQ1 genes. These genes provide instructions for making proteins that act as channels across the cell membrane. These channels transport positively charged atoms (ions) of potassium into and out of cells. In heart (cardiac) muscle, the ion channels produced from the KCNE2, KCNJ2, and KCNQ1 genes play critical roles in maintaining the heart's normal rhythm. Mutations in these genes have been identified in only a few families worldwide. These mutations increase the activity of the channels, which changes the flow of potassium ions between cells. This disruption in ion transport alters the way the heart beats, increasing the risk of syncope, stroke, and sudden death.
Most cases of atrial fibrillation are not caused by mutations in a single gene. This condition is often related to structural abnormalities of the heart or underlying heart disease. Additional risk factors for atrial fibrillation include high blood pressure (hypertension), diabetes mellitus, a previous stroke, or an accumulation of fatty deposits and scar-like tissue in the lining of the arteries (atherosclerosis). Although most cases of atrial fibrillation are not known to run in families, studies suggest that they may arise partly from genetic risk factors. Researchers are working to determine which genetic changes may influence the risk of atrial fibrillation.
How do people inherit familial atrial fibrillation?
Familial atrial fibrillation appears to be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
Source: National Institutes of Health
Recent Familial Atrial Fibrillation News and Articles
Studies Conducted at Vanderbilt University on Cardiology Research Recently Published
2012 OCT 29 (NewsRx) -- By a News Reporter-Staff News Editor at Cardiovascular Week
-- Investigators publish new report on Cardiology Research. According to news reporting out of Nashville, Tennessee, by NewsRx editors, research stated, "The aim of this study was to test the hypothesis
that 2 common polymorphisms in the chromosome
4q25 region that have been associated with atrial fibrillation (AF) contribute to the variable penetrance
of familial AF. Although mutations in ion channels, gap junction proteins
, and signaling molecules have been described for Mendelian forms of AF, penetrance is highly variable."
Our news journalists obtained a quote from the research from Vanderbilt University, "Recent studies have consistently identified 2 common single-nucleotide polymorphisms in the chromosome 4q25 region as independent AF susceptibility alleles. Eleven families in which AF was present in >= 2 members who also shared a candidate gene mutation were studied. These mutations were identified in all subjects with familial lone AF (n = 33) as well as apparently unaffected family members (age >50 years with no AF; n = 17). Mutations were identified in SCN5A (n = 6), NPPA (n = 2), KCNQ1 (n = 1), KCNA5 (n = 1), and NKX2.5 (n = 1). In genetic association analyses, unstratified and stratified according to age of onset of AF and unaffected age >50 years, there was a highly statistically significant association between the presence of both common (rs2200733 and rs10033464) and rare variants and AF (unstratified p = 1 x 10(-8), stratified [age of onset <50 years and unaffected age >50 years] p = 7.6 x 10(-5)) (unstratified p< 0.0001, stratified [age of onset <50 years and unaffected age >50 years] p< 0.0001). Genetic association analyses showed that the presence of common 4q25 risk alleles predicted whether carriers of rare mutations developed AF (p = 2.2 x 10(-4)). Common AF-associated 4q25 polymorphisms modify the clinical expression of latent cardiac ion channel and signaling molecule gene mutations associated with familial AF."
According to the news editors, the research concluded: "These findings support the idea that the genetic architecture of AF is complex and includes both rare and common genetic variants."
For more information on this research see: Chromosome 4q25 Variants Are Genetic Modifiers of Rare Ion Channel Mutations Associated With Familial Atrial Fibrillation. Journal of the American College of Cardiology, 2012;60(13):1173-1181. Journal of the American College of Cardiology can be contacted at: Elsevier Science Inc, 360 Park Ave South, New York, NY 10010-1710, USA.
Our news journalists report that additional information may be obtained by contacting M.D. Ritchie, Vanderbilt University, Sch Med, Dept. of Pharmacol, Nashville, TN 37323, United States.
Keywords for this news article include: Genetics, Nashville, Tennessee, Ion Channels, United States, Heart Disease, Atrial Fibrillation, Cardiac Arrhythmias, Cardiology Research, Membrane Glycoproteins, North and Central America, Membrane Transport Proteins
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2012, NewsRx LLC