Analysis of DNA reaping big gains

No one knew what was wrong with the one-week-old infant in the summer of 2012. Born healthy, he had come down with a soaring fever and severe diarrhea. There was no sign of an infection - and he was getting worse.

Desperate for a clue, the baby's physician at Yale-New Haven Hospital appealed to a team of Yale genetic specialists. If a flaw in the baby's genes was causing the mysterious illness, scouring his family's DNA for the mutation could provide insights that might save his life.

Researchers worked furiously, but the infant's body was shutting down. Just 23 days old, he passed away a day before the results came back.

The DNA analysis in the tragic case, however, was not for naught: It would help the researchers understand the disease - and ultimately have ripple effects that no one expected.

In the space of a few short years, DNA sequencing has changed from a technology whose medical promise is largely theoretical to a tool that is regularly used to gain insight into unexplained and rare diseases.

"This is truly a revolution; it's a fundamental revolution in how pediatricians are looking after patients," said Dr. Stephen Kingsmore, director of the center for pediatric genomic medicine at Children's Mercy Hospital in Kansas City, Mo., who was not involved in the Connecticut case. "We now have this ability to take children with a mystery disease and apply genome. . . sequencing and identify the cause of their disease fairly routinely."