title: Clinical characteristics of patients with non-specific and non-categorized mitochondrial diseases.
abstract: OBJECTIVE
  Mitochondrial disease is a heterogeneous disorder entity induced by defects in mitochondrial respiratory chain complex (MRC). A significant portion of patients with MRC defect will not conform to a specific, known syndrome. We have analysed the clinical features of 108 Korean paediatric patients with non-specific and non-categorized mitochondrial disease.
  
  
  METHODS
  We retrospectively reviewed the clinical and laboratory features of 108 paediatrics patients with non-specific and non-categorized mitochondrial diseases who showed defects in MRC activity, confirmed by spectrophotometric biochemical enzyme assay of their muscles.
  
  
  RESULTS
  Neuromuscular involvement was noted in all patients, with developmental delay and seizure accounting for 92.6% and 77.8% of total patients respectively. Various extraneurological symptoms were observed. Most patients exhibited MRC I defect, accounting for 100 (92.6%) patients. The most common brain magnetic resonance imaging (MRI) finding was diffuse cerebral atrophy. However, in 23.1% of patients, no notable changes were visible on MRI.
  
  
  CONCLUSIONS
  Mitochondrial respiratory chain complex I defect was the most common finding in this study. Though neuromuscular symptoms predominated, with presence of numerous extraneurological findings, we could not find any novel symptoms that might be unique to this category of mitochondrial disease. But, comparatively, more patients presented with unremarkable birth histories and normal brain MRI findings.
authors: Department of Pediatrics, Severance Children's Hospital, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors: Jeong Tae
authors: JT
authors: Kim
authors: Yun Jin
authors: YJ
authors: Lee
authors: Young Mock
authors: YM
authors: Lee
authors: Hoon Chul
authors: HC
authors: Kang
authors: Joon Soo
authors: JS
authors: Lee
authors: Heung Dong
authors: HD
authors: Kim
mesh_terms: D000140:Acidosis, Lactic / Q000209:etiology; D000293:Adolescent; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000209:etiology; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D028361:Mitochondrial Diseases / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009132:Muscles / Q000378:metabolism / Q000473:pathology*; D012189:Retrospective Studies; D012640:Seizures / Q000209:etiology; D055815:Young Adult
chemical_list: D024101:Mitochondrial Proteins