The School of Medicine is among 20 sites participating in a nationwide, $11 million study of optimizing stroke prevention in children with sickle-cell anemia.

Led by neurologist Robert Adams of the Medical College of Georgia and funded by the National Heart, Lung and Blood Institute, the STOP II study aims to determine how long children with sickle-cell disease should receive regular blood transfusions to minimize their risk of stroke.

The original STOP study, conducted from 1995 to 1997, found that regular blood transfusions could reduce stroke risk by 90 percent among children with sickle-cell disease who were at increased risk for stroke.

Because regular transfusion therapy has risks, including potentially harmful buildup of iron in the organs, researchers now hope to learn whether children whose stroke risk has been reduced through transfusions can stop receiving blood at some point without losing the therapy's protective benefits.

Thomas Adamkiewicz, assistant professor of pediatrics at Emory, is the principal investigator for the Atlanta centers participating in the STOP II study.

The centers are the Georgia Comprehensive Sickle-Cell Center at Grady Health System; the Hematology Oncology Center at Children's Healthcare of Atlanta at Scottish Rite; and the AFLAC Cancer Center and Blood Disorder Service at Children's Healthcare of Atlanta at Egleston.

Sickle-cell anemia is a blood disorder characterized by abnormal crescent-like red blood cells whose twisted shape makes them unable to pick up oxygen molecules from the lungs and carry them to the tissues.

About one in 10 children with sickle-cell disease are at risk for stroke; this risk appears to decline in early adulthood.