Featured Research

from universities, journals, and other organizations

Spontaneous mutations play a key role in congenital heart disease

Date:
May 12, 2013
Source:
Howard Hughes Medical Institute (HHMI)
Summary:
Although genetic factors contribute to congenital heart disease, many children born with heart defects have healthy parents and siblings, suggesting that new mutations that arise spontaneously —- known as de novo mutations —- might contribute to the disease. New research shows that about 10 percent of these defects are caused by genetic mutations that are absent in the parents of affected children.

Although genetic factors contribute to congenital heart disease, many children born with heart defects have healthy parents and siblings, suggesting that new mutations that arise spontaneously -- known as de novo mutations -- might contribute to the disease.

"Until recently, we simply didn't have the technology to test for this possibility," says Howard Hughes Medical Institute (HHMI) investigator~Richard Lifton. Lifton, who is at Yale School of Medicine, together with Christine Seidman, an HHMI investigator at Brigham and Women's Hospital and colleagues at Columbia, Mt. Sinai, and the University of Pennsylvania, collaborated to study congenital heart disease through the National Heart Lung and Blood Institute's Pediatric Cardiac Genomics Consortium.

Using robust sequencing technologies developed in recent years, the researchers compared the protein-coding regions of the genomes of children with and without congenital heart disease and their parents, and found that new mutations could explain about 10 percent of severe cases. The results demonstrated that mutations in several hundred different genes contribute to this trait in different patients, but were concentrated in a pathway that regulates key developmental genes. These genes affect the epigenome, a system of chemical tags that modifies gene expression. The findings were published online in the journal Nature on May 12, 2013.

For the current study, the investigators began with 362 families consisting of two healthy parents with no family history of heart problems and a child with severe congenital heart disease. By comparing genomes within families, they could pinpoint mutations that were present in each child's DNA, but not in his or her parents. The team also studied 264 healthy families to compare de novo mutations in the genomes of healthy children.

The team focused their gene-mutation search on the exome -- the small fraction of each person's genome that encodes proteins, where disease-causing mutations are most likely to occur. Children with and without congenital heart disease had about the same number of de novo mutations -- on average, slightly less than one protein-altering mutation each. However, the locations of those mutations were markedly different in the two groups. "The mutations in patients with congenital heart disease were found much more frequently in genes that are highly expressed in the developing heart," Seidman says.

The differences became more dramatic when the researchers zeroed in on mutations most likely to impair protein function, such as those that would cause a protein to be cut short. Children with severe congenital heart disease were 7.5 times more likely than healthy children to have a damaging mutation in genes expressed in the developing heart.

The researchers found mutations in a variety of genes, but one cellular pathway was markedly enriched in the children with heart defects. That pathway helps regulate gene activity by affecting how DNA is packaged inside cells. The body's DNA is wrapped around proteins called histones, and chemical tags called methyl groups are added to histones to control which genes are turned on and off. In children with congenital heart disease, the team found an excess of mutations in genes that affect histone methylation at two sites that are known to regulate key developmental genes.

Overall, the researchers found that de novo mutations contribute to 10 percent of cases of severe congenital heart disease. Roughly a third of this contribution is from the histone-methylation pathway, Lifton says. He also notes that a mutation in just one copy of a gene in this pathway was enough to markedly increase the risk of a heart defect.

Direct sequencing of protein-coding regions of the human genomes to hunt down de novo mutations has only been applied to one other common congenital disease -- autism. In that analysis, Lifton and his colleagues at Yale, as well as HHMI investigator Evan Eichler and colleagues at University of Washington, found mutations in some of the same genes mutated in congenital heart disease, and the same histone modification pathway appears to play a major role in autism as well, raising the possibility that this pathway may be perturbed in a variety of congenital disorders, Lifton says.

Even if the disease can't be prevented, identifying the mutations responsible for severe heart defects might help physicians better care for children with congenital heart disease. "After we repair the hearts of these children, some children do great and some do poorly," Seidman says. Researchers have long suspected that this might be due to differences in the underlying causes of the disease. Understanding those variations might help doctors improve outcomes for their patients.


Story Source:

The above story is based on materials provided by Howard Hughes Medical Institute (HHMI). Note: Materials may be edited for content and length.


Journal Reference:

  1. Samir Zaidi, Murim Choi, Hiroko Wakimoto, Lijiang Ma, Jianming Jiang, John D. Overton, Angela Romano-Adesman, Robert D. Bjornson, Roger E. Breitbart, Kerry K. Brown, Nicholas J. Carriero, Yee Him Cheung, John Deanfield, Steve DePalma, Khalid A. Fakhro, Joseph Glessner, Hakon Hakonarson, Michael J. Italia, Jonathan R. Kaltman, Juan Kaski, Richard Kim, Jennie K. Kline, Teresa Lee, Jeremy Leipzig, Alexander Lopez, Shrikant M. Mane, Laura E. Mitchell, Jane W. Newburger, Michael Parfenov, Itsik Pe’er, George Porter, Amy E. Roberts, Ravi Sachidanandam, Stephan J. Sanders, Howard S. Seiden, Mathew W. State, Sailakshmi Subramanian, Irina R. Tikhonova, Wei Wang, Dorothy Warburton, Peter S. White, Ismee A. Williams, Hongyu Zhao, Jonathan G. Seidman, Martina Brueckner, Wendy K. Chung, Bruce D. Gelb, Elizabeth Goldmuntz, Christine E. Seidman, Richard P. Lifton. De novo mutations in histone-modifying genes in congenital heart disease. Nature, 2013; DOI: 10.1038/nature12141

Cite This Page:

Howard Hughes Medical Institute (HHMI). "Spontaneous mutations play a key role in congenital heart disease." ScienceDaily. ScienceDaily, 12 May 2013. <www.sciencedaily.com/releases/2013/05/130512140609.htm>.
Howard Hughes Medical Institute (HHMI). (2013, May 12). Spontaneous mutations play a key role in congenital heart disease. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2013/05/130512140609.htm
Howard Hughes Medical Institute (HHMI). "Spontaneous mutations play a key role in congenital heart disease." ScienceDaily. www.sciencedaily.com/releases/2013/05/130512140609.htm (accessed August 21, 2014).

Share This




More Health & Medicine News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Ramen Health Risks: The Dark Side of the Noodle

Ramen Health Risks: The Dark Side of the Noodle

AP (Aug. 21, 2014) South Koreans eat more instant ramen noodles per capita than anywhere else in the world. But American researchers say eating too much may increase the risk of diabetes, heart disease and stroke. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Non-Inherited Mutations Account for Many Heart Defects

May 12, 2013 New mutations that are absent in parents but appear in their offspring account for at least 10 percent of severe congenital heart disease, reveals a massive genomics ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins