Question special

I wanted to start off by thanking the authors and experts who have agreed to join in on this important and timely discussion about the Precision Medicine Initiative. Each morning, I will post one question for the panel's consideration, although other moderators and guests may post questions throughout the day.
Today, I'll kick things off by asking what is precision medicine, and what are some examples of precision medicine? It might be perhaps helpful to parse this conversation into three broad categories of disease: 1) cancer, 2) monogenic disorders such as cystic fibrosis, where a single mutation explains the majority of disease risk in a given patient, and 3) polygenic disorders such as type 2 diabetes, where many genetic variants distributed across many genes collectively influence disease risk.