Medical mystery: Sifting through DNA haystack

James Verbsky is drawn to pediatrics by its ethical simplicity - the notion that you do anything to save a child. Yet as the doctor talks with colleagues at Children's Hospital of Wisconsin in the summer of 2009, he finds himself doubting their proposal for 4-year-old Nicholas Volker. They want to sequence Nicholas' DNA.

The boy in the Batman cape has a mysterious disease marked by painful holes leading from his intestine to his skin. Fecal matter leaks through the holes. In 2 1/2 years, Nicholas has made more than 100 trips to the operating room.

Verbsky, a 39-year-old immune specialist, has run every test he can think of to pin down the source of Nicholas' disease. So have the other doctors. They are running out of options.