Researchers have identified a gene that directly affects the production of a form of hemoglobin that is instrumental in modifying the severity of the inherited blood disorders sickle cell disease and thalassemia.
The discovery could lead to breakthrough therapies for sickle cell disease and thalassemia, which could potentially eliminate the devastating and life-threatening complications of these diseases, such as severe pain, damage to the eyes and other organs, infections, and stroke.
"Human Fetal Hemoglobin Expression is Regulated by the Developmental Stage-Specific Repressor BCL11A," is published online in Science December 4. The study was conducted by researchers at Children's Hospital Boston and Dana-Farber Cancer Institute and supported by the National Institutes of Health's National Heart, Lung, and Blood Institute (NHLBI) and National Institutes of Diabetes and Digestive and Kidney Diseases, and by the Howard Hughes Medical Institute.
Hemoglobin is the protein in red blood cells that carries oxygen to the body's tissues. In sickle cell disease, hemoglobin is abnormal and sticks together. The red blood cells become stiff and sickle-shaped, causing them to block blood vessels and rob tissues of necessary blood and oxygen. In thalassemia, the body has trouble producing adult forms of hemoglobin.
Other studies have shown that in patients with sickle cell disease, those who continue to produce fetal hemoglobin (HbF) have much milder forms of sickle cell anemia. For years, scientists have sought ways to increase HbF production in patients with sickle cell disease and thalassemia.
Researchers report that by suppressing a gene called BCL11A, HbF production improves dramatically. Their findings provide new insights into the mechanisms involved in the body's switch from producing fetal hemoglobin to adult hemoglobin and identify a potential new target for therapies that could dramatically alter the course of sickle cell anemia and thalassemia.
The researchers built upon their recently reported results of genome-wide association studies that identified several gene variants associated with HbF levels. BCL11A was found to have the greatest effect on HbF levels. In the follow-up study reported today, they report that BCL11A encodes a transcription factor that directly suppresses HbF production.