*Corresponding author:Manuela Zlamy, Clinic for Pediatrics I, Department of Pediatrics, Medical University of Innsbruck, Anichstraße 35; 6020 Innsbruck, Austria
Received: May 30, 2018; Published: June 12, 2018
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Introduction: Mitochondrial disorders have a clinical and genetic heterogeneity which often complicates the diagnostic process especially in critically ill patients. Exome sequencing can help to generate a definite diagnosis in a rather short time.
Case Presentation: A boy presented with inspiratory stridor, respiratory insufficiency, progressive muscular hypotonia, poor head control and sucking, and hypersomnia at three months of age. He got ventilator dependent and developed cardiomyopathy within weeks. The progressive multisystem disease leads to the suspicion of a mitochondrial disorder. As neither the clinical nor the metabolic changes or the diagnostic procedures performed seemed indicative of a specific mitochondrial disorder, we performed exome sequencing. This revealed a known homozygous mutation (c.418G>A, p.Glu140Lys) in SCO2.
Discussion:Retrospectively, the combination of progressive encephalomyopathy and inspiratory stridor could have been the diagnostic clue for SCO2 deficiency. However, given the enormous clinical and genetic heterogeneity it is nearly impossible to diagnose a mitochondrial disorder with single gene analysis in the restricted time frame clinicians’ face when caring for life- threatening ill infants. This case illustrates both the importance of concise clinical characterization and the power of exome sequencing as first line diagnostic procedure..