Navigation Links
Severe heart defect likely caused by genetic factors

CINCINNATI - Hypoplastic Left Heart Syndrome (HLHS), a severe cardiovascular malformation that is difficult to treat and often lethal, is caused primarily by genetic factors, according to a new study by researchers at Cincinnati Childrens Hospital Medical Center. The study to be published in the Oct. 16 edition of the Journal of the American College of Cardiology is the first to show the high heritability and likely genetic underpinnings of HLHS and recommend a direction for future research into its cause, development and possible therapeutic strategies.

Our study demonstrates that HLHS has high heritability, suggesting it is caused almost entirely by genetic effects instead of environmental factors, and that families with a child with HLHS carry a significant recurrence risk of HLHS or related heart defects. This should be considered by physicians when counseling parents to ensure they are aware of potential risks, said Robert B. Hinton, Jr., M.D., a physician and researcher at Cincinnati Childrens and the studys lead author.

HLHS is rare, occurring in about two of every 10,000 children born, Dr. Hinton said. Of those children born with HLHS approximately 20 percent die during the first months of life, he added. Children with HLHS suffer from restricted blood and oxygen flow because their hearts are abnormally shaped with an underdeveloped left side. This can include an undersized and/or malformed left ventricle (the hearts primary pumping chamber), aorta, aortic valve or mitral valve. Despite significant advances in diagnosis and therapy, the condition remains challenging to treat and the specific causes remain unknown, Dr. Hinton said. Babies can survive HLHS by undergoing a series of three complex operations after birth or receiving a heart transplant.

The study at Cincinnati Childrens included 38 family-based test groups with a history of HLHS. Researchers found that 55 percent of those families had one or more blood relative with HLHS or an associated heart defect. Of 193 blood relatives evaluated between the ages of 3 days and 74 years, 21.4 percent had HLHS or associated heart defects. In families where one child already had HLHS, the risk of HLHS recurring in a sibling was 8 percent while the risk of a sibling having an HLHS-associated cardiovascular defect was 22 percent. In families where a child and one parent had HLHS, the recurrence risk increased dramatically to 21 percent for recurring HLHS and 25 percent for an associated defect. All participants were evaluated using echocardiography to determine specific phenotype, or the visible heart characteristics and defects found among the different family test groups. During those examinations researchers diagnosed 12 new cases of associated defects among relatives of HLHS patients.

Researchers recommend further studies to pinpoint specific genes responsible for the condition. Finding the genetic basis of HLHS could have significant implications for treating children with the disease, said D. Woodrow Benson, M.D., Ph.D., director of Cardiovascular Genetics at Cincinnati Childrens and the studys senior author. This includes identifying possible interventions during fetal life (such as catheter-based procedures), the most appropriate postoperative drug therapies for individual children and determining the potential risks for failure of the right ventricle.

By using family based linkage analysis, where specific genetic traits are mapped, it should be possible to identify the genes that cause the disease, Dr. Benson said. Once we know what genes are involved we can study how the disease developments, which may lead to new treatment approaches.

Earlier studies in animals indicate HLHS may develop because of embryonic alterations in blood flow, such as a premature narrowing of the aortic valve and foramen ovale (which in the fetal heart allows blood to enter the left atrium from the right). Other studies have pointed to the role of certain genes (TBX5 and IRX1) in the formation of defective heart chambers with distinct shapes, functionality and molecular structure. Based on analysis of how these genes function, scientists hypothesize that HLHS may result from a primary defect in the growth of muscle tissue during the hearts development.

Currently there are no experimental models to clarify the relative contributions of these two hypotheses to the development of HLHS, Dr. Hinton said. An important step forward in this research will be to understand the degree to which these hypothetical causes actually contribute to the condition.


Contact: Nick Miller
Cincinnati Children's Hospital Medical Center

Related medicine news :

1. Low Cholesterol Linked to Severe Depression and Violent Behavior in Men
2. Patients With Severe Hemophilia At Risk Of Developing Osteoporosis
3. Severe stress weakens immunity
4. Severe Acute respiratory Syndrome (SARS)
5. WHO Travel Advice to prevent spread of "Severe Acute Respiratory Syndrome (SARS)
6. Traffic pollution linked to severe asthma attacks
7. Severe sleep apnea can cause liver problems
8. Scientists Unveil Mechanism Behind Resistance to Severe Malaria
9. Strong Magnetic Stimulation Can Help Treating Severe Depression
10. Patients Suffering From Severe Mental Diseases Are At Risk Of Being Crime Victims
11. Acute Toxicity Of Nano-Scale Zinc Powder: Severe Renal Damage And Anemia
Post Your Comments:
(Date:11/27/2015)... ... 2015 , ... Intellitec Solutions announced today that they have ... as Microsoft’s official group for end users of Dynamics SL ERP software, the ... experts and representatives. Intellitec Solutions’ membership status demonstrates their ongoing commitment to the ...
(Date:11/27/2015)... ... ... CBD College is proud to announce that on November 20th, ... its Diagnostic Medical Sonography program. CBD College is honored to join this very short ... universities in the state of California make the cut. CBD College is officially the ...
(Date:11/27/2015)... ... November 27, 2015 , ... Indosoft Inc., developer and ... of Asterisk 11 LTS (Long Term Support) into its Q-Suite 5.10 product line. ... 5.10 up-to-date with a version of Asterisk that will receive not only security ...
(Date:11/26/2015)... Ashburn, VA (PRWEB) , ... November 26, 2015 ... ... Planners, an American Express Travel Representative. As a franchise owner, Somu now offers ... range of cruise, destination wedding packages, private cruise sales, as well as, cabin ...
(Date:11/26/2015)... ... 2015 , ... WorldCare International, Inc., the first company to ... Benefits Conference. The Employee Benefits Conference was hosted by the International Foundation of ... 2015. The conference was held at the Hawaii Convention Center in Honolulu, Oahu, ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... , Nov. 25, 2015 ... addition of the "Global Brain Monitoring ... offering. --> ) has ... Brain Monitoring Devices Market 2015-2019" report ... and Markets ( ) has announced ...
(Date:11/25/2015)... 25, 2015  Linden Care, LLC, a retail specialty ... for patients suffering from chronic pain, said today that ... Restraining Order (TRO) enjoining Express Scripts from unilaterally terminating ... --> --> The company ... legal options. --> --> ...
(Date:11/25/2015)... 25, 2015  Henry Schein, Inc., the world,s largest ... dental, medical and animal health practitioners, will unveil at ... Henry Schein ConnectDental® Pavilion , which brings together for ... solutions designed to help any practice or laboratory enter ... for a schedule of experts appearing at the Pavilion. ...
Breaking Medicine Technology: