In the March 26, 2018 episode of the fictional medical TV drama
The Good Doctor, the physicians are trying to treat a college student with injuries from a hazing incident and possibly other causes.
In one scene, one of the doctors on the team suggests that the student may have paroxysmal nocturnal hemoglobinuria. Another doctor says "PNH? The chances are 1 in a million" and the topic of PNH does not come up again.
The chances of acquiring PNH may be close to 1 in a million, but the chances of an average person having PNH at any given time are closer to 16 in a million. The TV show writers apparently didn't distinguish
incidence from
prevalence.
The incidence and prevalence of PNH are still not well-established.
Incidence measures the number of new PNH cases diagnosed per year, or over another time period. The Aplastic Anemia & MDS International Foundation reports estimates of 400 to 500 new PNH annual diagnoses in the U.S. Since the U.S. population is 325.7 million, that's an annual incidence rate of about 1.2 to 1.5 cases per million people.
Prevalence measures the number of people having PNH within the population.
Past studies in Great Britain and France found an incidence rate of about 1.3 cases per million people and a prevalence of about 16 cases per million people. That would put the U.S. PNH population at over 5000 people.
Viewers may not have learned much about PNH from this TV episode, but at least the disease was pronounced properly!