Study identifies genetic factors that may explain long-term survival of some patients with sickle cell anemia

Image shows sickle-shaped red blood cell next to normal red blood cell.

Researchers in Africa are reporting new insights into the genetic factors that may explain why some people with sickle cell anemia to have long-term survival into their 50s and 60s while others die in childhood. The findings could lead to better treatments for those with the genetic blood disorder, they say.

Of the 300,000 babies born with sickle cell disease each year worldwide, about 80% are in sub-Saharan Africa, the researchers note.  About 50% of African children with the disease die before they turn five years old.  But in some of the same regions of sub-Saharan Africa, there are some sickle cell patients who live much longer, surviving into their 50s and 60s. The question is: Why?

To find out, the researchers conducted genetic sequencing among 192 people with sickle cell anemia in sub-Saharan Africa, specifically Cameroon.  They further divided the group into long-term survivors over 40 years, a “stroke” group (at least one episode of stroke), and a “random” group of patients younger than 40 years without stroke.

The researchers found that the “long survivor” group had certain genetic factors that seemed to have a protective effect. This includes genetic variants that were associated with lower blood pressure and genetic changes that allow them to efficiently utilize the micronutrient selenium.  The researchers found that patients who had experienced strokes tended to have a mutation in the blood coagulation pathway. The identification of these genes may lead to interventions, such as nutritional supplements, what may one day benefit patients with sickle cell disease, the researchers suggest.

Their study, partly funded by NHLBI, appeared in Clinical and Translational Medicine.