Monthly Archives: January 2015

Up to 8 percent of people from India, Pakistan, Bangladesh and other South Asian countries carry a mutated gene that causes heart failure and potentially fatal heart attacks.

A new study demonstrates how this gene mutation impairs the heart's ability to pump blood. Results could point the way to eventual treatments and prevention strategies for an estimated 55 million people of South Asian descent worldwide, including 200,000 people in the United States, who carry the potentially fatal mutation.

The study, led by Sakthivel Sadayappan, PhD, MBA, of Loyola University Chicago Stritch School of Medicine, is published in theJournal of Biological Chemistry, a publication of the American Society for Biochemistry and Molecular Biology.

The mutation causes hypertrophic cardiomyopathy, the most common form of inherited cardiac disease and the leading cause of sudden cardiac death in young people. Previous studies by Dr. Sadayappan and other researchers have found that between 5 percent and 8 percent of South Asians carry the mutation. Carriers have about a 80 percent chance of developing heart failure after age 45. Dr. Sadayappan first reported the mutation in 2001 at the World Congress of the International Society for Heart Research, and has been studying it ever since. He said that, based on a report from one of his collaborators, the mutation likely arose in a single person roughly 33,000 to 55,000 years ago. The mutation then spread throughout South Asia.

The mutated gene encodes for a protein, called cardiac myosin binding protein-C (cMyBP-C), that controls cardiac muscle contractions and is critical for the normal functioning of the heart. In the mutated gene, 25 base pairs (DNA letters) are missing. As a result, the tail end of the protein is altered.

In his new study, Dr. Sadayappan and colleagues introduced the mutated gene into adult rat cardiomyocytes (heart muscle cells) in a petri dish. These cells were compared with cardiomyocytes that received a normal gene.

In cells with the mutant gene, the cMyBP-C protein was not incorporated into sarcomeres, the basic units of heart muscle. So rather than helping the sarcomeres contract properly, the mutant protein floated around the cell's cytoplasm, producing a toxic effect. The study showed, for the first time, that expression of the mutant protein is sufficient to cause cardiac dysfunction.

The findings point the way toward future treatments that would remove the mutant protein from cells and introduce normal cMyBP-C protein. Researchers also hope to identify lifestyle and environmental risk factors that aggravate hypertrophic cardiomyopathy in people who carry the gene mutation.

Dr. Sadayappan and colleagues concluded that determining the disease mechanism will help in developing therapies, and is the "first priority to prevent the development of heart failure in millions of carriers worldwide."

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Up to eight percent of Asians carry gene mutation that causes heart failure

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Newswise MAYWOOD, Il. Up to 8 percent of people from India, Pakistan, Bangladesh and other South Asian countries carry a mutated gene that causes heart failure and potentially fatal heart attacks.

A new study demonstrates how this gene mutation impairs the hearts ability to pump blood. Results could point the way to eventual treatments and prevention strategies for an estimated 55 million people of South Asian descent worldwide, including 200,000 people in the United States, who carry the potentially fatal mutation.

The study, led by Sakthivel Sadayappan, PhD, MBA, of Loyola University Chicago Stritch School of Medicine, is published in the prestigious Journal of Biological Chemistry, a publication of the American Society for Biochemistry and Molecular Biology.

The mutation causes hypertrophic cardiomyopathy, the most common form of inherited cardiac disease and the leading cause of sudden cardiac death in young people. Previous studies by Dr. Sadayappan and other researchers have found that between 5 percent and 8 percent of South Asians carry the mutation. Carriers have about a 80 percent chance of developing heart failure after age 45. Dr. Sadayappan first reported the mutation in 2001 at the World Congress of the International Society for Heart Research, and has been studying it ever since. He said that, based on a report from one of his collaborators, the mutation likely arose in a single person roughly 33,000 to 55,000 years ago. The mutation then spread throughout South Asia.

The mutated gene encodes for a protein, called cardiac myosin binding protein-C (cMyBP-C), that controls cardiac muscle contractions and is critical for the normal functioning of the heart. In the mutated gene, 25 base pairs (DNA letters) are missing. As a result, the tail end of the protein is altered.

In his new study, Dr. Sadayappan and colleagues introduced the mutated gene into adult rat cardiomyocytes (heart muscle cells) in a petri dish. These cells were compared with cardiomyocytes that received a normal gene.

In cells with the mutant gene, the cMyBP-C protein was not incorporated into sarcomeres, the basic units of heart muscle. So rather than helping the sarcomeres contract properly, the mutant protein floated around the cells cytoplasm, producing a toxic effect. The study showed, for the first time, that expression of the mutant protein is sufficient to cause cardiac dysfunction.

The findings point the way toward future treatments that would remove the mutant protein from cells and introduce normal cMyBP-C protein. Researchers also hope to identify lifestyle and environmental risk factors that aggravate hypertrophic cardiomyopathy in people who carry the gene mutation.

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Up to 8 Percent of Indians and Other South Asians Carry Gene Mutation That Causes Heart Failure

Kansas City, Mo. -- January 15, 2015 -- A new study published in the American Journal of Human Genetics demonstrates the continued important contributions from the Center for Pediatric Genomic Medicine at Children's Mercy Hospital in Kansas City, Mo. The study describes a new pediatric mitochondrial syndrome and discovery of the responsible gene, called CLPB. Dr. Carol Saunders and her team partnered with collaborators in Denmark to report their collective findings based on gene mapping and exome sequencing in five children with CLPB-related disease. These patients had strikingly similar clinical findings including cataracts, severe psychomotor regression during febrile episodes, epilepsy, neutropenia with frequent infections, urinary excretion of 3-methylglutaconic aciduria, and death in early childhood.

"This research once again highlights the power of genomic medicine in the diagnosis and discovery of rare pediatric conditions," said Saunders, clinical laboratory director of the Center for Pediatric Genomic Medicine "In this case, we have identified one of the many genes, CLPB, involved in mitochondrial diseases. These findings emphasize the importance of basic research into the characterization of human CPLB gene function and will pave the way for the diagnosis of other patients."

The Center for Pediatric Genomic Medicine at Children's Mercy was the first genome center in the world inside a children's hospital, and the center's STAT-Seq test for critically ill newborns was one of TIME magazine's Top 10 Medical Breakthroughs of 2012. Learn more at http://www.childrensmercy.org/genomics.

About Children's Mercy Kansas City

Children's Mercy, located in Kansas City, Mo., is one of the nation's top pediatric medical centers. The 354-bed, not-for-profit hospital provides care for children from birth through the age of 21, and has been ranked by U.S. News & World Report as one of "America's Best Children's Hospitals." For the third time in a row, Children's Mercy has achieved Magnet nursing designation, awarded to fewer than seven percent of all hospitals nationally, for excellence in quality care. Its faculty of 600 pediatricians and researchers across more than 40 subspecialties are actively involved in clinical care, pediatric research, and educating the next generation of pediatric subspecialists.

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FOR INTERVIEWS WITH DR. CAROL SAUNDERS, CONTACT JAKE JACOBSON AT JAJACOBSON@CMH.EDU

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Discovery of CLPB gene associated with a new pediatric mitochondrial syndrome