Background: Up to 15% of infants with asymptomatic congenital cytomegalovirus (CMV) infection will experience some degree of sensorineural hearing loss. Many infants who fail newborn hearing screening (NHS) are likely to have congenital CMV infection, but may escape definitive virologic identification because diagnostic evaluation may not commence until several weeks or months of age, making differentiation between congenital and postnatal CMV infection difficult. Early diagnosis linking virologic identification of congenital CMV infection to infants failing NHS may improve diagnostic precision and enhance opportunities for therapeutic intervention.
Methods: The goal of this study was to compare newborn dried blood spots from Minnesota infants who had failed NHS, and were designated for referral, with control infants who passed NHS, for the presence of CMV DNA by real-time PCR, using hybridization probes for the CMV gene UL54.
Results: Of 479 infants with a failed NHS (bilateral failure), 13 had CMV DNA present in the blood spot (2.7%). This compared with only 2/479 positive results from a control group of infants who passed the NHS (0.4%; P = 0.007, Fisher exact test). Comparisons of the glycoprotein B (gB) genotype as well as direct DNA sequencing of selected positives revealed that PCR positive samples represented unique clinical isolates. The mean viral load among the 15 positive samples was 1.6 × 103 genomes/microgram of total DNA.
Conclusions: Newborn bloodspot CMV screening by real-time PCR may be a useful and rapid adjunct to functional NHS and may enable more rapid etiologic diagnosis of sensorineural hearing loss in newborns.
From the Departments of *Pediatrics and †Otolaryngology, University of Minnesota Medical School, Minneapolis, MN; and the ‡Minnesota Department of Health, Newborn Screening Program, Minneapolis, MN.
Accepted for publication May 21, 2009.
Supported by a grant from the March of Dimes Birth Defects Foundation (to L.A.S.) and by the American Legion (to M.R.S.). The authors received funding from grant 1R01NS055101.
Address for correspondence: Mark R. Schleiss, MD, Department of Pediatrics and University of Minnesota Medical School, MMC 391 420 Delaware St SE, Minneapolis, MN 55455-0374. E-mail: email@example.com.
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