Researchers at Children’s Hospital, University Medical Center Ljubljana, Slovenia; Molecular Neurogenetics, Milan, Italy; and Paracelsus Medical University, Salzburg, Austria, evaluated the functional outcome of 22 children with mitochondrial diseases. Twelve children (55%) had pyruvate dehydrogenase complex deficiency, 4 had Leigh syndrome, and 10 had respiratory chain enzyme deficiencies. Complex IV was the most frequent enzyme deficiency. The morbidity was high, but the mortality was low (18%). Total Mitochondrial Disease Criteria score was above 7, 82% above 8. Using the Pediatric Evaluation of Disability Inventory and scaled scores, a large variability in functional skills was seen in self-care, mobility, and social function. Also, a large variability in caregiver assistance, from independence to total dependence on assistance was observed. Few patients used assistive devices. Children with mitochondrial disease have severe limitations in cognition and communication and are dependent on their parents. Functional status is a necessary part of the evaluation of children with mitochondrial disease. 
COMMENT. Evaluation of skills in self-care, mobility, and social function is important in the management of children with mitochondrial disease. The Pediatric Evaluation of Disability Inventory is an effective bedside measure of estimating a child’s need for caregiver assistance and assistive devices.