Basically this mutation is shown to protect against malaria, but it causes an issue with producing a molecule needed for the creation of ATP (energy your body needs)
So while they can offer a protective effect to the subject they could need transfusions or other treatment to stay healthy.
Subject 1 & 2 had similar biomarkers, and subject 3 had different markers causing a type of misread that made them transfusion dependent.
That’s my understanding at least
I thought you were talking about this movie
https://en.m.wikipedia.org/wiki/Crash_(2004_film)