Sickle Cell Disease

What is sickle cell disease?

Sickle cell disease (SCD) is an inherited blood disorder in which red blood cells can become stiff, sticky and often shaped like the letter C. Normal red blood cells are smooth and flexible, like the letter O, and can move easily through blood vessels. But sickle cells tend to cluster together. These clusters can create blockages in your child's small blood vessels, stopping the movement of healthy, oxygen-carrying blood. These blockages can lead to sudden pain anywhere in the body, as well as damage to the body tissues and organs over time. The altered structure of the red blood cell also causes it to break down more rapidly, leading to a chronically low blood count, or anemia.

SCD primarily affects children of African descent and Hispanics of Caribbean ancestry. It also occurs in children of Middle-Eastern and Indian descent.

Gene therapy shows early promise against sickle cell

Manny Johnson is the first to participate in a clinical trial that is testing a novel gene therapy approach for treating SCD.


Doctor examining a patient who was treated using a gene therapy for sickle cell disease,

Our approach to sickle cell disease at Dana-Farber/Boston Children's

Dana-Farber/Boston Children's is an international leader in improving treatment and quality of life for children with SCD. Our Sickle Cell Disease Program provides children with access to world-renown pediatric hematologists, top-rated nursing care and the latest treatment options, including hydroxyurea and stem cell transplantation, in addition to a novel gene therapy approach.

Gene therapy for sickle cell

The sickle cell gene therapy clinical trial focuses on newborn hemoglobin. Newborns have a different hemoglobin called fetal hemoglobin that doesn't sickle. The goal of this clinical trial is to flip the switch in SCD red cells back to fetal hemoglobin to prevent sickling from occurring.

Dana Farber/Boston Children's researchers identified that variations in the expression of a gene known as BCL11A can affect levels of fetal hemoglobin and spent several years devising a way to prevent BCL11A production, resulting in a clinical trial. The treatment process is similar to a stem cell transplant. A patient's blood stem cells are removed, and then undergo months of gene modification to reduce BCL11A expression and induce production of healthy fetal hemoglobin. The gene-modified cells are then given back to the patient via an intravenous infusion to silence the sickle-producing adult hemoglobin.

Learn more about the Gene Therapy Program.