Proteins detectable in urine may offer a relatively simple screening target to identify children with obstructive sleep apnea, a study of 120 children suggests.
Dr. David Gozal of the University of Chicago and associates studied 90 children referred to a pediatric sleep medicine center in Louisville, Ky., for evaluation of habitual snoring and suspected sleep-disordered breathing. A total of 60 children met polysomnographic and clinical criteria for OSA, while 30 had primary snoring. The study also included as controls 30 children who didn't snore.
All children underwent overnight polysomnography, and urine samples were collected upon waking. Two-dimensional differential in-gel electrophoresis was used to assess protein expression in urine (Am. J. Respir. Crit. Care Med. 2009;180:1253–61).
In children with obstructive sleep apnea, levels of 12 urinary proteins differed from those in children with primary snoring or in controls.
Three proteins increased in OSA—uromodulin, orosomucoid-1, and urocortin-3—and one protein decreased, kallikrein-1.
Abnormal levels of two or more of these four proteins predicted OSA with 100% sensitivity and 96.5% specificity. Abnormal levels of at least three of the proteins produced 95% sensitivity and 100% specificity.
Dr. Gozal serves on a Merck & Co. speakers bureau. Some of the other study researchers have received corporate funding to develop biomarker assays and to study pediatric sleep apnea.