Reducing the False-Positive Rate for Isovalerylcarnitine in Expanded Newborn Screening

The isodecyl neopentanoate is an ingredient used in the cosmetic industry to prepare a nipple fissure balm. We report on 12 newborns that showed elevated C5-acylcarnitine levels upon newborn screening following treatment with balm. The first 3 neonates were immediately recalled for confirmatory test...

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Main Authors: Sara Poggiali BSc, MT, Daniela Ombrone BSc, Giulia Forni BSc, Sabrina Malvagia BSc, Silvia Funghini BSc, PhD, Massimo Mura Pharm Sc, Elisabetta Pasquini MD, Laura Santoro BSc, Vincenzo Bellavia BSc, Orazia Maria Granata BSc, Cinzia Castana MD, Kathleen S. McGreevy PhD, Tommaso Silvano Aronica MD, Giancarlo la Marca Pharm Sc
Format: Article
Language:English
Published: SciELO 2016-07-01
Series:Journal of Inborn Errors of Metabolism and Screening
Online Access:https://doi.org/10.1177/2326409816661355
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Summary:The isodecyl neopentanoate is an ingredient used in the cosmetic industry to prepare a nipple fissure balm. We report on 12 newborns that showed elevated C5-acylcarnitine levels upon newborn screening following treatment with balm. The first 3 neonates were immediately recalled for confirmatory tests and resulted negative for both isovaleric acidemia and short/branched chain acyl-CoA dehydrogenase deficiency. In the other 9 cases, the immediate recall was avoided by applying a new second-tier test able to confirm the presence of pivaloylcarnitine. The concentration of C5-acylcarnitine was measured in the days following the suspension of balm application. Abnormal concentrations of C5-acylcarnitine did not seem to be associated with free carnitine deficiency, probably due to the short time of exposure. A direct correlation between balm ingestion and the elevation in pivaloylcarnitine has been demonstrated in 10 adult volunteers. The commercial balm containing a pivalic acid derivative is causal of false-positive results during newborn screening, and it could have the potential to cause secondary carnitine deficiency when used chronically.
ISSN:2326-4594