[P1-148] Neuromuscular involvement in children with mitochondrial disease: a single centre experience
Introduction and Methods:
Neuromuscular involvement has been reported to be frequent in mitochondrial disease. We reviewed the clinical records of 22 children and young adults below 25 years old with confirmed mitochondrial disease by either genetic mutation or respiratory chain enzymology study and had follow up in our centre between 2006 and 2015. Data on genetic test, muscle enzymology study, nerve conduction study, electromyography and muscle biopsy findngs were systematically collected and analyzed.
Results:
6/22 (27.3%) patients have neuropathy. 2 of them had axonal sensorimotor polyneuropathy, 1 had axonal motor polyneuropathy, 2 had demyelinating sensorimotor polyneuropathy, and 1 had mixed type of polyneuropathy. The patient with SURF1 mutation had demyelinating polyneuropathy, whereas the 2 patients with POLG mutation had demyelinating sensorimotor and axonal motor polyneuropathy respectively. 2/22 (9.1%) patients had concomitant myopathy and neuropathy. 9/22 (40.9%) were confirmed to have myopathy by either electromyography (3/9) or muscle biopsy (6/9). All of them had normal creatine kinase levels. 2/8 patients with complex IV deficiency had COX negative fibres on muscle biopsy.
Discussion:
The overall prevalence of neuromuscular involvement reported in this series is 59.1%, comparable to those reported in literature. No definite association of genetic mutation with the type of neuromuscular involvement was observed, and most cases with complex IV deficiency did not have COX negative fibres shown up on the muscle biopsy.
Neuromuscular involvement has been reported to be frequent in mitochondrial disease. We reviewed the clinical records of 22 children and young adults below 25 years old with confirmed mitochondrial disease by either genetic mutation or respiratory chain enzymology study and had follow up in our centre between 2006 and 2015. Data on genetic test, muscle enzymology study, nerve conduction study, electromyography and muscle biopsy findngs were systematically collected and analyzed.
Results:
6/22 (27.3%) patients have neuropathy. 2 of them had axonal sensorimotor polyneuropathy, 1 had axonal motor polyneuropathy, 2 had demyelinating sensorimotor polyneuropathy, and 1 had mixed type of polyneuropathy. The patient with SURF1 mutation had demyelinating polyneuropathy, whereas the 2 patients with POLG mutation had demyelinating sensorimotor and axonal motor polyneuropathy respectively. 2/22 (9.1%) patients had concomitant myopathy and neuropathy. 9/22 (40.9%) were confirmed to have myopathy by either electromyography (3/9) or muscle biopsy (6/9). All of them had normal creatine kinase levels. 2/8 patients with complex IV deficiency had COX negative fibres on muscle biopsy.
Discussion:
The overall prevalence of neuromuscular involvement reported in this series is 59.1%, comparable to those reported in literature. No definite association of genetic mutation with the type of neuromuscular involvement was observed, and most cases with complex IV deficiency did not have COX negative fibres shown up on the muscle biopsy.