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Cardiac conduction improvement in two heterozygotes for primary carnitine deficiency on l-carnitine supplementation

Authors


Kyriakie Sarafoglou, MD, Department of Pediatrics, Divisions of Endocrinology, and Genetics and Metabolism, University of Minnesota, MMC 8404 13-124 PWB, 420 Delaware St. S.E., Minneapolis, MN 55455, USA.
Tel: +1 612 624 5409;
fax: +1 612 626 5262;
e-mail: saraf010@umn.edu

Abstract

Sarafoglou K, Tridgell AHC, Bentler K, Redlinger-Grosse K, Berry SA, Schimmenti LA. Cardiac conduction improvement in two heterozygotes for primary carnitine deficiency on l-carnitine supplementation.

Expanded newborn screening (NBS) for free carnitine levels has led to the identification of a larger number of heterozygous infants of undiagnosed mothers affected with systemic primary carnitine deficiency (PCD), which in turn leads to the identification of other undiagnosed heterozygous family members. There is an increasing recognition that individuals heterozygous for mutations of genes involved in fatty acid oxidation (FAO) may become symptomatic under environmental stress (fasting, prolonged exercise and illness). Considering the importance of carnitine in FAO, its role in heart and bowel function and in lipid metabolism, what is still little known is the phenotypic variability, biochemical parameters and clinical course of PCD heterozygotes with consistently low-to-normal levels to low levels of carnitine over a lifetime. We report on three generations of a family—an asymptomatic PCD heterozygous infant identified through NBS that led to the diagnosis of her asymptomatic PCD-affected mother and the heterozygous status of the maternal grandparents who report some cardiac symptoms that overlap with PCD that improved with l-carnitine supplementation.

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