• routine_newborn_screening

Types of Tests for ADA-SCID

Early detection of SCID can dramatically improve the chances of survival. If diagnosis is delayed and the infant or child starts to experience the severe opportunistic infections associated with the disorder, the chances for successful treatment are significantly diminished.1-3

There is a consensus among specialists that nearly all cases of SCID could be diagnosed at birth if routine blood counts were done and flow cytometry, as well as T-cell counts, were performed when lymphocyte levels are below the normal range in newborns. Once a diagnosis is confirmed, treatment can begin immediately.4,5

Routine Screening for SCID

Not all states require routine screening for SCID (including ADA-SCID) in newborns. The test is routinely offered, but not yet required in some states, and in others the test is required, but not yet implemented.6

The Advisory Committee on Heritable Disorders in Newborns and Children has recommended routine newborn screening for SCID and will be determining whether national screening should be mandatory.5

Physical Examination

There may also be clues in chest X-rays, including the absence of a thymic shadow, lung abnormalities, and signs of pneumonia, and in infants with ADA-SCID, the presence of skeletal abnormalities may aid in the diagnosis. Unusually persistent, severe, or opportunistic infections are the most common presentation, particularly viruses, fungi, or bacteria, and indicate a possible SCID diagnosis.2,7,8

References: 1. Buckley RH, Schiff RI, Schiff SE, et al. Human severe combined immunodeficiency: genetic, phenotypic, and functional diversity in one hundred eight infants. J Pediatr. 1997;130:378-387. 2. Hershfield MS, Mitchell BS. Immunodeficiency diseases caused by adenosine deaminase deficiency and purine nucleoside phosphorylase deficiency. In: Scriver CR, Beaudet AL, Sly WS, Valle D, eds. The Metabolic and Molecular Bases of Inherited Disease. 7th ed. New York, NY: McGraw-Hill; 1995:1725-1768. 3. Gennery AR, Cant AJ. Diagnosis of severe combined immunodeficiency. J Clin Pathol 2001;54:191–195. 4. Huang H, Manton KG. Newborn screening for severe combined immunodeficiency (SCID): a review. Front Biosci. 2005;10:1024-1039. 5. Secretary of Health and Human Services response to November 22, 2009 and February 25, 2010 Letters (May 21, 2010) Available at
http://www.hrsa.gov/heritabledisorderscommittee/correspondence/response5_21_2010.pdf. Accessed February 28, 2011. 6. National Newborn Screening and Genetics Resource Center. National Newborn Screening Status Report. Available at http://genes-r-us.uthscsa.edu/nbsdisorders.pdf Accessed February 28, 2011. 7. Schwartz RA, Sinha S. Pediatric severe combined immunodeficiency. Available at http://emedicine.medscape.com/article/888072-overview. Accessed February 28, 2011. 8. Wong HK. Dermatologic Manifestations of severe combined immunodeficiency. Available at http://emedicine.medscape.com/article/1051355-overview. Accessed February 28, 2011.