Andersen-Tawil Syndrome News and Articles
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What is Andersen-Tawil syndrome?
Anderson-Tawil syndrome is a disorder that causes episodes of muscle weakness (periodic paralysis), changes in heart rhythm (arrhythmia), and developmental abnormalities. The most common changes affecting the heart are ventricular arrhythmia, which is a disruption in the rhythm of the heart's lower chambers, and long QT syndrome. Long QT syndrome is a heart condition that causes the heart (cardiac) muscle to take longer than usual to recharge between beats. If untreated, the irregular heartbeats can lead to discomfort, fainting (syncope), or cardiac arrest.
Physical abnormalities associated with Andersen-Tawil syndrome typically affect the head, face, and limbs. These features often include a very small lower jaw (micrognathia), dental abnormalities, low-set ears, widely spaced eyes, and unusual curving of the fingers or toes (clinodactyly). Some affected people also have short stature and an abnormal curvature of the spine (scoliosis).
Two types of Andersen-Tawil syndrome are distinguished by their genetic causes. Type 1, which accounts for about 60 percent of all cases of the disorder, is caused by mutations in the KCNJ2 gene. The remaining 40 percent of cases are designated as type 2; the cause of these cases is unknown.
How common is Andersen-Tawil syndrome?
Andersen-Tawil syndrome is a rare genetic disorder; its incidence is unknown. About 100 people with this condition have been reported worldwide.
What genes are related to Andersen-Tawil syndrome?
Mutations in the KCNJ2 gene cause Andersen-Tawil syndrome.
The KCNJ2 gene provides instructions for making a protein that forms a channel across cell membranes. This channel transports positively charged atoms (ions) of potassium into muscle cells. The movement of potassium ions through these channels is critical for maintaining the normal functions of muscles used for movement (skeletal muscles) and cardiac muscle. Mutations in the KCNJ2 gene alter the usual structure and function of potassium channels or prevent the channels from being inserted correctly into the cell membrane. Many mutations prevent a molecule called PIP2 from binding to the channels and effectively regulating their activity. These changes disrupt the flow of potassium ions in skeletal and cardiac muscle, leading to the periodic paralysis and irregular heart rhythm characteristic of Andersen-Tawil syndrome.
Researchers have not determined the role of the KCNJ2 gene in bone development, and it is not known how mutations in the gene lead to the developmental abnormalities often found in Andersen-Tawil syndrome.
How do people inherit Andersen-Tawil syndrome?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, a person with Andersen-Tawil syndrome inherits the mutation from one affected parent. Other cases result from new mutations in the KCNJ2 gene. These cases occur in people with no history of the disorder in their family.
Source: National Institutes of Health
Osaka University Publishes Research in Medical Science
2012 NOV 5 (NewsRx) -- By a News Reporter-Staff News Editor at Cardiovascular Week
-- Fresh data on Medical Science are presented in a new report. According to news reporting from Osaka, Japan, by NewsRx journalists, research stated, "A 37-year-old Japanese woman experienced aborted sudden cardiac
death from ventricular fibrillation
and was diagnosed with Andersen-Tawil syndrome
by genetic analysis
that revealed 2 mutations in the KCNJ2 gene
. Although she received an implantation of implantable cardioverter defibrillator and beta-blocker therapy
, the frequency of premature ventricular contraction and bidirectional ventricular tachycardia
did not decrease."
The news correspondents obtained a quote from the research from Osaka University, "Her ventricular arrhythmias increased after a full stomach test and a neostigmine provocation test, and reduced after cibenzoline administration, which indicates the relation with vagal tone. Moreover, increasing the pacing rate significantly decreased them."
According to the news reporters, the research concluded: "These findings indicate that the arrhythmia was bradycardia-dependent in this case."
For more information on this research see: Andersen-Tawil Syndrome Associated with Aborted Sudden Cardiac Death: Atrial Pacing Was Effective for Ventricular Arrhythmias. American Journal of the Medical Sciences, 2012;344(3):248-250. American Journal of the Medical Sciences can be contacted at: Lippincott Williams & Wilkins, 530 Walnut St, Philadelphia, PA 19106-3621, USA. (Lippincott Williams and Wilkins - www.lww.com; American Journal of the Medical Sciences - journals.lww.com/amjmedsci/pages/default.aspx)
Our news journalists report that additional information may be obtained by contacting Y. Kuramoto, Osaka University, Dept. of Adv Cardiovasc Therapeut, Grad Sch Med, Osaka, Japan.
Keywords for this news article include: Asia, Osaka, Japan, Genetics, Neurology, Arrhythmia, Cardiology, Medical Science, Sudden Cardiac Death, Andersen-Tawil Syndrome
Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2012, NewsRx LLC