(NPR) – “They were relatively young, thin and kind of undernourished looking,” says Boyne.

Normally, that would point to Type 1 diabetes, where individuals are unable to make their own insulin and can become underweight.

But these 13 patients never experienced a common symptom of Type 1 — ketoacidosis. That occurs when the body runs out of insulin and starts burning fat for fuel, which can lead the blood to become dangerously acidic. (Read More)