title: Mitochondrial DNA analysis by multiplex denaturing high-performance liquid chromatography and selective sequencing in pediatric patients with cardiomyopathy.
abstract: OBJECTIVE
  Mitochondrial DNA testing is typically performed by targeted mutation analysis only. We applied a more comprehensive approach to study the mitochondrial genome in 24 pediatric patients with idiopathic cardiomyopathy.
  
  
  METHODS
  Patients in the cohort did not show overt multisystemic disease and were previously tested for mutations in a subset of structural genes associated with cardiomyopathy. Mutation screening of the mitochondrial DNA by multiplex denaturing high-performance liquid chromatography was complemented by sequence analysis.
  
  
  RESULTS
  We identified 130 individual (unique) sequence changes. Among several potentially pathogenic changes, a novel heteroplasmic mutation in nicotinamide adenine dinucleotide dehydrogenase subunit 4 (10677G>A) was identified in one fraternal twin with worse clinical symptoms than his sibling. Another proband carried homoplasmic mutation 13708G>A (in nicotinamide adenine dinucleotide dehydrogenase subunit 5) that has been associated with Leber's hereditary optic neuropathy.
  
  
  CONCLUSIONS
  Changes in mitochondrial DNA may represent a relatively rare cause of idiopathic pediatric cardiomyopathies and/or influence their phenotypic expression. Interpretation of variants with uncertain pathogenicity, however, currently impedes clinical diagnostic use of comprehensive mitochondrial DNA testing. Whereas combined use of multiplex denaturing high-performance liquid chromatography and sequencing is more comprehensive than targeted mutation analysis, measurement of additional functional parameters, such as tissue respiratory chain activity, remains important to establishing a definitive diagnosis.
authors.affiliation: Department of Pathology and Pediatrics, Stanford University Medical Center, Stanford, California 94305, USA. ischrijver@stanfordmed.org
authors.forename: Iris
authors.initials: I
authors.lastname: Schrijver
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Pique
authors.forename: Ilana
authors.initials: I
authors.lastname: Traynis
authors.forename: Curt
authors.initials: C
authors.lastname: Scharfe
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Sehnert
mesh_terms: D000293:Adolescent; D000328:Adult; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015331:Cohort Studies; D004252:DNA Mutational Analysis / Q000379:methods*; D004272:DNA, Mitochondrial / Q000737:chemistry*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male
chemical_list: D004272:DNA, Mitochondrial