Separate studies of the human genome have found tantalising clues to the inherited causes of testicular cancer and non-inherited causes of congenital heart disease, journals reported on Sunday.

University of Pennsylvania researchers looked at the DNA of more than 13,000 men, comparing the DNA code of those with testicular cancer -- the commonest form of cancer diagnosed among young men today -- against men who were otherwise healthy.

They found four new variants that increase the risk of this disease, bringing the tally of known mutations to 17, according to research reported in Nature Genetics.

Meanwhile, investigators at the Yale School of Medicine found a clutch of gene mutations, absent in parents but found in their offspring, which account for at least 10 percent of cases of severe congenital heart disease, a birth defect that afflicts nearly one percent of babies.

"Most interestingly, the set of genes mutated in congenital heart disease unexpectedly overlapped with genes and pathways mutated in autism," said Richard Lifton, a professor of genetics.

"These findings suggest there may be common pathways that underlie a wide range of common congenital diseases."

The study appears in the journal Nature.

Genomics is one of the fastest-moving areas of medical research.

Identifying genetic signatures associated with disease opens up the prospect of DNA tests to identify people most at risk. They also throw open avenues of research to block or reverse the disease.