Correction

The Hemophilias — From Royal Genes to Gene Therapy

N Engl J Med 2001; 345:384August 2, 2001

Article

The Hemophilias — From Royal Genes to Gene Therapy (Review Article, N Engl J Med 2001:344;1773 - 1779) . On page 1778, the sentences that begin on line 18 of the left-hand column should have read, “One study in patients with hemophilia B is evaluating the safety of intramuscular injections of an adeno-associated virus.⁶¹ At the lowest dose of the adeno-associated virus containing the gene for factor IX, plasma levels of factor IX ranged from 0.5 to 1.6 percent of normal and less use of concentrates was evident.”