Montefiore News Releases
New Studies Link Gene Mutations to Some Cases of Sudden Death
New York City, NY (October 26, 2009) - A mother spends sleepless nights after the unexplained overnight death of her previously healthy 22-month old daughter. Will her even younger child also succumb during the night? She doesn't know and is fearful of going to sleep.
Because a baseball bat is found near her body, a loving husband is charged with beating his wife to death. Later it is determined she sustained a head injury when she collapsed from a disturbance of her heart rhythm.
These are just two of many frightening and tragic cases of sudden and unexplained death. Now, with genetic and cardiac testing, there may be answers -- and help -- in sight.
Scientists and clinicians at the Montefiore-Einstein Center for Cardiogenetics have teamed up and found that genetic mutations leading to Long QT Syndrome (LQTS) could be causing electrical malfunctioning of the heart resulting in the mysterious deaths more commonly known as Sudden Infant Death Syndrome (SIDS) and Sudden Unexplained Death Syndrome (SUDS) in people older than 12 months of age.
LQTS is one of several inherited diseases that result from an abnormality of the heart's electrical system, which must "recharge" between beats. In adults and children with LQTS, the electrical system takes too long to "recharge" resulting in abnormal heart rhythms that can lead to palpitations, seizures, fainting or sudden death because the heart cannot pump blood adequately.
Two recent studies indicate a link between sudden death and LQTS. In the journal Circulation, a report from Vanderbilt University Medical Center was released indicating that variations in the gene NOS1AP increase the risk of cardiac symptoms and sudden death in patients who have LQTS. In addition, researchers from Baylor College of Medicine published a report in the journal Science Translational Medicine finding that the most common gene for a syndrome associated with abnormal heart rhythms and sudden death triggers epileptic seizures and could explain sudden unexplained death in epilepsy.
The Montefiore-Einstein Center for Cardiogenetics offers state-of-the art cardiac, neurological and genetic testing for LQTS and interventions for families who have suffered the tragic loss of a loved one due to SIDS or SUDS.
There are as many as 3,000 deaths from SIDS and a much larger number of deaths from SUDS in the United States annually. Ten to fifteen percent of SIDS deaths and nearly half of SUDS deaths can be attributed to these genetic mutations that are transmitted from parent to child.
"The sudden unexpected death of an infant, child or adolescent is always a tragedy, made more so because, in most cases, no medical reason or cause is identified," said Christine Walsh, MD, a cardiologist at The Children's Hospital at Montefiore specializing in heart rhythm disturbances in children and a Center co-director. "After burying a child, these grieving parents are left to wonder whether one or more of their surviving children are destined to meet the same fate. By providing early diagnosis and prompt treatment of at-risk members and by offering counseling, education and emotional support, our Center is helping these families by giving them back control over their lives," Dr. Walsh said.
Abnormal rhythms can be triggered by exercise (especially swimming or diving), noise, emotion or sudden awakening from sleep by an alarm clock, telephone or thunder. With a certain type of LQTS, death is more likely to occur during sleep. Determining the type of LQTS is very helpful in individualizing treatment.
"The Montefiore-Einstein Center for Cardiogenetics is one of the very few centers of its kind in the world studying this phenomenon and working with at-risk families who might possess these ‘sudden death' genes," said Robert Marion, MD, a genetics expert at Montefiore and a Center co-director. "Clinicians, researchers and scientists from Montefiore Medical Center and Albert Einstein College of Medicine will perform ‘molecular autopsies' when possible by examining the DNA of people who died and are suspected of having mortality genes and whose autopsy did not reveal a cause of death," Dr. Marion said. "If positive, the family members can be tested for the same genetic defect and genetic counseling and treatment will be offered."
Treatment options include beta-blocker medications and an internal defibrillator (ICD/pacemaker) that can shock the heart back to a normal rhythm. Lifestyle changes are extremely important, including avoiding competitive sports, strenuous activity and loud noises and reducing stress. It is also necessary to avoid certain medications that lengthen the QT interval on the electrocardiogram, which is the portion that measures how long it takes for the heart to "recharge." With proper management, adults and children with LQTS can lead full lives.
"With Montefiore's doctors translating scientists' observations for use at the bedside, we are, for the first time, able to identify at-risk members of these families, offering treatments that will save lives," Dr. Marion said.
"Our work in the lab seeks to understand how inherited mutations put one at risk for sudden death, by identifying behaviors, medicines and environmental factors that will reduce the risks," said Thomas McDonald, MD, professor of Cardiology at Einstein who is a researcher and heart rhythm expert in adults and a Center co-director. "The synergy of scientists working with clinicians enables us to offer a great deal more than we could if we worked alone. We clearly are more than the sum of our parts," Dr. McDonald noted.