Objectives: Mitochondrial respiratory chain deficiencies are known for their high clinical variability. Difficult to diagnose, the prevalence of these diseases is probably underestimated.
Methods: We report 18 children diagnosed with respiratory chain deficiency at the Tours University Hospital over the past 10 years.
Results: Three clinical profiles can be distinguished depending on the age at onset of the first symptoms: the neonatal period (4 cases), between 1 month and 2 years of age (10 cases), and after 10 years (4 cases). However, no clinical feature appears specific of any age group. In contrast, respiratory chain analysis on liver biopsy was very informative for all our patients at any age and with any clinical presentation, even with predominant neurological symptoms.
Conclusions: These biochemical analyses support the diagnosis of mitochondrial disorders in view of molecular analysis, which nevertheless frequently remains inconclusive. These investigations should benefit from the new molecular screening technologies based on DNA chips that can identify the genomic mutations responsible for these severe and relatively frequent diseases.