title: Exome sequencing identifies primary carnitine deficiency in a family with cardiomyopathy and sudden death.
abstract: Pediatric cardiomyopathy is a rare but severe disease with high morbidity and mortality. The causes are poorly understood and can only be established in one-third of cases. Recent advances in genetic technologies, specifically next-generation sequencing, now allow for the detection of genetic causes of cardiomyopathy in a systematic and unbiased manner. This is particularly important given the large clinical variability among pediatric cardiomyopathy patients and the large number of genes (>100) implicated in the disorder. We report on the performance of whole-exome sequencing in members of a consanguineous family with a history of pediatric hypertrophic cardiomyopathy and sudden cardiac death, which led to the identification of a homozygous stop variant in the SLC22A5 gene, implicated in primary carnitine deficiency, as the likely genetic cause. Targeted carnitine tandem mass spectrometry analysis in the patient revealed complete absence of plasma-free carnitine and only trace levels of total carnitine, further supporting the causality of the SLC22A5 variant. l-carnitine supplementation in the proband led to a rapid and marked clinical improvement. This case illustrates the use of exome sequencing as a systematic and unbiased diagnostic tool in pediatric cardiomyopathy, providing an efficient route to the identification of the underlying cause, which lead to appropriate treatment and prevention of premature death.
authors.affiliation: Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Najim
authors.initials: N
authors.lastname: Lahrouchi
authors.affiliation: Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Elisabeth M
authors.initials: EM
authors.lastname: Lodder
authors.affiliation: Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Mohammed V University, Rabat, Morocco.|Département de génétique médicale, Institut National d'Hygiène, Rabat, Morocco.
authors.forename: Maria
authors.initials: M
authors.lastname: Mansouri
authors.affiliation: Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Rafik
authors.initials: R
authors.lastname: Tadros
authors.affiliation: Centre de Cardiologie, Rabat, Morocco.
authors.forename: Layla
authors.initials: L
authors.lastname: Zniber
authors.affiliation: Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Mohammed V University, Rabat, Morocco.|Département de génétique médicale, Institut National d'Hygiène, Rabat, Morocco.
authors.forename: Najlae
authors.initials: N
authors.lastname: Adadi
authors.affiliation: Department of Pediatric Cardiology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Sally-Ann B
authors.initials: SB
authors.lastname: Clur
authors.affiliation: Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Karin Y
authors.initials: KY
authors.lastname: van Spaendonck-Zwarts
authors.affiliation: Department of Anatomy, Embryology & Physiology, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Alex V
authors.initials: AV
authors.lastname: Postma
authors.affiliation: Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Mohammed V University, Rabat, Morocco.
authors.forename: Abdelaziz
authors.initials: A
authors.lastname: Sefiani
authors.affiliation: Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Mohammed V University, Rabat, Morocco.
authors.forename: Ilham
authors.initials: I
authors.lastname: Ratbi
authors.affiliation: Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Connie R
authors.initials: CR
authors.lastname: Bezzina
mesh_terms: D000328:Adult; D009202:Cardiomyopathies / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics*; D002331:Carnitine / Q000097:blood / Q000172:deficiency* / Q000627:therapeutic use; D018388:Codon, Terminator / Q000235:genetics*; D003645:Death, Sudden; D059472:Exome; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D027701:Organic Cation Transport Proteins / Q000235:genetics*; D010375:Pedigree; D000074058:Solute Carrier Family 22 Member 5
chemical_list: D018388:Codon, Terminator; D027701:Organic Cation Transport Proteins; C492020:SLC22A5 protein, human; D000074058:Solute Carrier Family 22 Member 5; D002331:Carnitine