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Primary Carnitine (OCTN2) Deficiency Without Neonatal Carnitine Deficiency
L de Boer1, L A J Kluijtmans, E Morava
1Department of Pediatrics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands, ldeboer@kpnplanet.nl.
JIMD Reports
|February 23, 2013
Summary
Newborns may have normal total carnitine levels despite primary carnitine deficiency due to placental transfer. Genetic testing is crucial for diagnosing nonclassical cases, even with initially high carnitine levels.
Area of Science:
- Biochemistry
- Genetics
- Neonatal Medicine
Background:
- Primary carnitine deficiency diagnosis typically relies on very low free and total carnitine levels.
- Neonatal screening can identify infants with potential carnitine metabolism disorders.
Purpose of the Study:
- To report a case of primary carnitine deficiency with a nonclassical presentation in a neonate.
- To highlight the importance of genetic diagnostics and follow-up for atypical cases.
Main Methods:
- Newborn screening for carnitine levels.
- Carnitine profile assessment after supplementation withdrawal.
- DNA mutation analysis of the OCTN2 (SLC22A5) gene.
Main Results:
- A neonate presented with a total carnitine level of 67% of normal.
- After supplementation cessation, free carnitine dropped to 10.4 μmol/l and total carnitine to 12.7 μmol/l.
- Homozygous c.136C>T (p.P46S) mutation in the OCTN2 gene confirmed primary carnitine deficiency.
Conclusions:
- Neonates with primary carnitine deficiency can exhibit normal or elevated total carnitine levels due to placental transfer.
- Regular follow-up and genetic analysis are vital for diagnosing primary carnitine deficiency in nonclassical presentations.
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