A new and groundbreaking study conducted by Children's Hospital & Research Center Oakland hematologists is the first of its type to examine the natural history of heritable blood disorder hemoglobin H (HbH) which is on the rise in the United States. Patients with hemoglobin H have a moderately-severe anemia because of gene defects leading to insufficient production of hemoglobin. The disorder does not usually cause significant health problems, except in cases of hemoglobin H Constant Spring (HCS), a severe form of the disease, which often results in life-threatening anemia. Extended study of the evolution of the disease, made possible by newborn screening for the disease in California, has shown all forms of hemoglobin H are manageable and there is a decreased rate of morbidity if diagnosed at birth.
Children's Hospital & Research Center Oakland pediatric hematologist Ashutosh Lal, MD, and colleagues conducted the study that appears in this week's New England Journal of Medicine (February 24, 2011). The study included 86 patients, 23 with HCS, during a 15-year period and provides a previously undocumented natural history of the disease in young children.
The State of California, using Children's Hospital Oakland as its reference laboratory, is currently the only state in the country that universally screens all births for Hemoglobin H disease. As a result of this vital service, almost 1,000 cases have been diagnosed since the late 1990s.
Based on this success, Elliott Vichinsky, MD, Director of Children's Hematology/Oncology division, proposed to the United States Secretary of Health and Human Services Advisory Committee on Heritable Disorders in Newborns and Children that testing for hemoglobin H should be included in all national newborn screening programs. The Committee ultimately did not pass Dr. Vichinsky's proposal, citing a lack of evidence evaluating the benefits of early identification and treatment of hemoglobin H. Dr. Lal's study fills that critical gap and as a result, preliminary feedback from agency leadership indicates that the proposal for national newborn screening may be reconsidered.
The study demonstrated that patients with HbH exhibited relatively normal growth and development without needing blood transfusions, but patients with HCS were at high-risk for life-threatening anemia even during infancy. Knowing that an ill infant has HCS avoids expending precious time -- which could save a young life-- and money trying to diagnose the problem.
The study also demonstrated that hemoglobin H is not restricted to the traditional Asian ethnic populations it was once exclusively associated with. Although the majority of patients studied (81%) had an Asian background, 5% were Hispanic, 3% were African American, and 10% had mixed ancestry.
One in 10,000 newborns in California is diagnosed with hemoglobin H disease. The screening of newborns for hemoglobin H was pioneered in California by collaboration between the State Newborn Screening Program and Children's Hospital & Research Center Oakland. When a baby is detected to have abnormal screening result, a blood sample is sent to Children's Hospital for confirmation of diagnosis. Dr. Lal's study shows that the advanced DNA testing at Children's Hospital Oakland can predict the course of the disease during childhood, which helps to ensure proper treatment for all patients.
Dr. Lal's study makes a strong case for extending the universal newborn screening for hemoglobin H at the national level. It provides information for policymakers to allocate resources for the identification of those diseases at birth where timely medical care can ensure lasting improvement in the quality of life.
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