Affiliations: Department of Pediatrics, Nijmegen Centre for
Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, Nijmegen,
The Netherlands | Department of Pediatric Physiotherapy, Radboud
University Nijmegen Medical Centre, Nijmegen, The Netherlands | Department of Pediatric Revalidation, Radboud
University Nijmegen Medical Centre, Nijmegen, The Netherlands | Department of Pediatric Psychology, Radboud University
Nijmegen Medical Centre, Nijmegen, The Netherlands | Department of Pediatric Cardiology, Radboud University
Nijmegen Medical Centre, Nijmegen, The Netherlands
Note: [] Correspondence: Dr. Eva Morava, Radboud University Nijmegen
Medical Centre, Department of Pediatrics, Nijmegen Centre for Mitochondrial
Disorders, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands. Tel.: +31
243619470; Fax: +31 243611600; E-mail: [email protected]
Abstract: In case of non-specific and relatively mild muscle symptoms, the
diagnosis of an inborn error of metabolism could be easily missed. Muscle pain
can be the first sign of a mitochondrial disorder, especially in combination
with motor developmental delay or associated organ dysfunction. Here we report
on six children with a distinctive pattern of symptoms in association with
variable, suboptimal mitochondrial dysfunction. This pattern exists of early
onset exercise intolerance, fatigue, feeding difficulties and concentration
problems associated with recurrent episodes of nocturnal hypothermia, muscle
pain and mild motor retardation. No endocrine, cardiac, immunologic,
neurodegenerative or psychiatric causes were found to explain these complaints.
Based on the presence of muscle pain, multisystem involvement and mild lactic
acidemia a mitochondrial disorder was suspected. We found decreased oxidation
capacity in muscle, confirming a suboptimal mitochondrial function in our
patients. Four out of five patients benefited from high dose riboflavin
therapy. We think pediatricians should be aware of the possibility of a
mitochondrial dysfunction in children presenting with a combination of diverse
but relatively mild, "aspecific" symptoms. We advise to use the Mitochondrial
Disease Criteria to evaluate the possibility of mitochondrial disease in these
children.
