Newborn Screening for SCID Saving Lives
Pediatric immunologists have long sought to screen for Severe Combined Immunodeficiency (SCID), a universally fatal disease that became widely known during the 1970s and '80s, when the world learned of David Vetter, a boy with X-linked SCID, who lived for 12 years in a plastic, germ-free bubble.
Wisconsin was the first state to screen newborns for SCID beginning in 2008. In 2010 U.S. Secretary of Health and Human Services Kathleen Sebelius endorsed the recommendation of an advisory committee calling for nationwide SCID screening, and several states since have followed Wisconsin's lead.
SCID is the first curable condition on the newborn screening panel of 30 genetic diseases. The test is a molecular-based assay designed to measure thymic function. More than 18 genetic mutations have been associated with the clinical phenotype of SCID and the central feature of this genetically heterogeneous disease is diminished thymic function.
Before newborn screening, early diagnosis of SCID was clearly shown to lead to better outcomes. In Wisconsin, which screens approximately 70,000 newborns annually, three cases of SCID have been identified and treated at American Family Children's Hospital during the past year. One infant underwent a successful bone marrow transplant at two months of age; another will undergo corrective gene therapy in the near future, and the third is undergoing bone marrow transplant evaluation.
"The ability to cure validates why we do this test," says Christine Seroogy, MD, a pediatric immunologist at American Family Children's Hospital in Madison. "We have already saved the lives of infants who would have succumbed to infection had we not been able to screen for the underlying immunodeficiency."
In addition to detecting SCID early, Dr. Seroogy says that other clinically significant T-cell lymphopenias have been detected with this newborn screening. Based on retrospective analyses, the incidence of SCID was estimated to be 1/100,000. A longer evaluation period is necessary to accurately define the true incidence of SCID, but initial data from newborn screening suggests the incidence may be as high as 1/30,000-45,000 births.