Genes Tell Only Part of the Story

I had intended to discuss President Obama’s plans for personalized precision medicine with my patient Barbara last week, but she missed her appointment. Or, more accurately, she arrived two hours late, made the usual giant fuss at the reception desk and had to be rescheduled.

I was disappointed. Barbara has some insight into the vortex of her own complications, and I thought she might help organize my thoughts.

Mr. Obama announced last month that his new budget included $215 million toward the creation of a national databank of medical information, intended to associate specific gene patterns with various diseases and to predict what genetic, lifestyle and environmental factors correlate with successful treatment. Once all those relationships are clarified, the path will open to drugs or other interventions that firm up the good links and interrupt the bad ones.

This step up the scientific ladder of medicine has many advocates. Researchers who sequence the genome are enthusiastic, as are those with a financial interest in the technology. Also celebrating are doctors and patients in the cancer community, where genetic...