Nav: Home

Genes responsible for severe congenital heart disease identified by Pitt researcher

May 22, 2017

PITTSBURGH, May 22, 2017 - The first known identification of two genes responsible for hypoplastic left heart syndrome (HLHS), a severe congenital heart defect, has been reported by researchers at the University of Pittsburgh School of Medicine. The findings are published today in the journal Nature Genetics.

Congenital heart disease, or structural abnormalities in the heart that are present at birth, affect up to 1 percent of all live births. HLHS is a rare congenital heart disease where the left side of the heart is poorly developed, resulting in an inability to effectively pump blood to the rest of the body. It occurs in about 2 to 3 of every 10,000 live births in the United States, and is fatal if left untreated.

Current treatment for HLHS involves multiple complex surgeries in the first few years of a child's life, and while effective in many patients, it does not improve heart function in many others. In those individuals, heart failure ensues and heart transplantation is required. The five-year survival rate for HLHS patients is approximately 50 to 70 percent.

Though genetic risk factors are known to play a role in HLHS, specific genes have been hard to identify.

"Studying diseases with complex genetics is extremely challenging. Our study has been made possible by leveraging findings from a large-scale analysis in mice to recover mutations causing congenital heart defects. This resulted in the recovery of the first mouse models of HLHS. Analysis of these mice with HLHS allowed us to identify for the first time two genes interacting in combination to cause HLHS," said Cecilia Lo, Ph.D., professor at Pitt's School of Medicine who also holds the F. Sargent Cheever Chair in Developmental Biology. "By understanding the genetics and biology of HLHS, this can facilitate development of new therapies to improve the prognosis for these patients."

Lo and her team used fetal ultrasound imaging to screen mice with experimentally induced mutations, looking for structural heart defects. From this screen, they recovered eight different mouse strains with structural and functional heart defects indicative of HLHS.

By comparing the genome of mice with the HLHS heart defects to the genome of normal mice, Lo and her team identified several hundred mutations in the HLHS mutant strains. Further analysis of these mutant mice indicated the genetic origins of HLHS likely involve many interacting genes. The relevance of these mutations was reinforced by the fact that many also were found in the same chromosomal regions previously shown to be associated with HLHS from human genetic studies.

In one mouse strain, they discovered that mutations in two genes, named Sap130 and Pcdha9, were required for HLHS. "Interestingly, HLHS was found only in animals with mutations in both genes. However, animals that had mutations with Pcdha9, but not Sap130, can display defects in the aorta, but with normal-sized left ventricles, suggesting interaction between the two genes is needed to cause all the features of HLHS," said Xiaoqin Liu, M.D., Ph.D., the first author of the new study and a research instructor in Lo's lab.

Using CRISPR-Cas9 gene editing in mice, the researchers confirmed that mutations in these two genes can cause HLHS. Additionally, they sequenced 68 HLHS patient samples and found one individual with rare mutations in both SAP130 and PCDHA genes.

Molecular analysis showed that heart cells in affected animals were poorly developed and had mitochondrial defects, indicating that Sap130-Pcdha9 gene interactions play a crucial role not only in heart development but also in regulating metabolic function of the cardiac muscle.

These findings suggest HLHS may be associated with a fundamental cellular defect in the heart muscle that can compromise blood flow in patients. This has important therapeutic implications, as surgical repair will not be able to address the cellular muscle defect in HLHS patients, noted Lo.

The researchers are investigating other mutations identified through the genetic screen and plan to undertake more genetic analysis of HLHS patients to better understand the molecular and genetic factors that cause the disease.
Other study authors included researchers from Pitt, The Jackson Laboratory, University of Rochester School of Medicine and Dentistry, Cincinnati Children's Hospital Medical Center, Children's National Medical Center, Boston Children's Hospital, University of San Diego School of Medicine and Medical College of Wisconsin.

The study was supported by National Institutes of Health grants U01-HL098180, R01-HL132024, R01-GM104412, S10-OD010340, R01-MH094564, OD011185, the Children's Heart Foundation, and the Junior Cooperative Society.

About the University of Pittsburgh School of Medicine

As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1998. In rankings recently released by the National Science Foundation, Pitt ranked fifth among all American universities in total federal science and engineering research and development support.

Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see

University of Pittsburgh Schools of the Health Sciences

Related Congenital Heart Disease Articles:

Genes responsible for severe congenital heart disease identified by Pitt researcher
Genes responsible for hypoplastic left heart syndrome identified using mouse models.
Ablation for atrial fibrillation proven safe and effective for patients with congenital heart disease, Penn study finds
In a new study presented today at the Heart Rhythm Society's 38th Annual Scientific Session in Chicago, researchers from the Perelman School of Medicine at the University of Pennsylvania have found that CHD patients -- even with complex defects -- can safely undergo ablation for AF, with similar success rates as patients with normal hearts.
Lessening radiation risk for children with congenital and acquired heart disease
Newly released recommendations for pediatric radiation safety will be discussed during the Society for Cardiovascular Angiography and Interventions (SCAI) 2017 Scientific Sessions in New Orleans.
High-throughput, in vivo validation of candidate congenital heart disease genes
Specific genetic errors that trigger congenital heart disease in humans can be reproduced reliably in Drosophila melanogaster -- the common fruit fly -- an initial step toward personalized therapies for patients in the future.
Women with high-risk congenital heart disease can have successful pregnancies
Women with high-risk congenital heart disease can have successful pregnancies but should seek counseling before conception to understand how their conditions could affect pregnancy and their child's health.
First US babies treated in study of adult stem cell therapy for congenital heart disease
In a first-in-children randomized clinical study, medical researchers at the University of Maryland School of Medicine (UM SOM) and the Interdisciplinary Stem Cell Institute (ISCI) at the University of Miami Miller School of Medicine have begun testing to see whether adult stem cells derived from bone marrow benefit children with the congenital heart defect hypoplastic left heart syndrome (HLHS).
Children dying preventable deaths from congenital heart disease
Over one million children are born with congenital heart disease (CHD) each year, and 90 percent are born in poor regions with little or no access to care.
Einstein scientist receives $7.5 million grant for congenital heart disease research
The National Institutes of Health has awarded Bernice Morrow, Ph.D., at Albert Einstein College of Medicine and collaborators at the Children's Hospital of Philadelphia a five-year, $7.5 million grant to study the genetics of congenital heart abnormalities.
Mother's blood sugar measurement associated with baby's congenital heart disease risk
For the first time, researchers have shown that the level of blood sugar measured in the first trimester of pregnancy may be associated with the risk of delivering a baby with congenital heart disease, according to a preliminary study presented at the American Heart Association's Scientific Sessions 2016.
Women with congenital heart disease have better shot at healthy pregnancies
New research from the Perelman School of Medicine at the University of Pennsylvania reveals that women with CHD who are deemed high risk by conventional measures are more likely to have safe, healthy pregnancies than current risk-assessments suggest.

Related Congenital Heart Disease Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...