At least 10 percent of severe genetic heart defects are caused by new gene mutations that were not passed down from patients' parents, a new study finds.

Congenital heart disease is the most common form of birth defect and occurs in nearly 1 percent of newborns.

"These findings provide new insight into the causes of this common congenital disease," senior study author Richard Lifton, chair of the genetics department at the Yale School of Medicine, said in a university news release.

Lifton's tream analyzed the genes of more than 1,800 people and identified hundreds of mutations that can cause congenital heart disease.

In particular, the investigators found that frequent mutations occurred in genes that affect what's known as histones. Histones are proteins that package DNA in the cell's nucleus and control the timing and activation of genes that may be key to fetal development.

The study was published online May 12 in the journal Nature.

"Most interestingly, the set of genes mutated in congenital heart disease unexpectedly overlapped with genes and pathways mutated in autism," Lifton said. "These findings suggest there may be common pathways that underlie a wide range of common congenital diseases."

"This is an important piece of the puzzle that gives us a clearer picture of the causes of congenital heart disease," Dr. Gary Gibbons, director of the U.S. National Heart, Lung, and Blood Institute, added in the news release. The institute funded the study.