The baby was gravely ill. Rapid sequencing turned around a diagnosis in 13 hours — and pointed to a treatment

When the boy was brought to the San Diego emergency department one night last October, he was inconsolable. Within about half an hour, clinicians had a clue of what was wrong: A CT scan showed signs of disease in the 5-week-old’s brain.

There was another clue, too, but also a portent: A decade earlier, the parents’ infant daughter had presented with some of the same symptoms at around the same age, but never received a diagnosis. She developed seizures and died at 11 months.

Read the rest…