title: Peripheral neuropathy is a common manifestation of mitochondrial diseases: a single-centre experience.
abstract: Peripheral neuropathy in mitochondrial diseases (MDs) may vary from a subclinical finding in a multisystem syndrome to a severe, even isolated, manifestation in some patients.
  
  
  
  To investigate the involvement of the peripheral nervous system in MDs extensive electrophysiological studies were performed in 109 patients with morphological, biochemical and genetic diagnosis of MD [12 A3243G progressive external ophthalmoplegia (PEO)/mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), 16 myoclonic epilepsy with ragged-red fibres (MERRF), four mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), 67 PEO with single or multiple deletions of mitochondrial DNA, 10 others].
  
  
  
  A neuropathy was found in 49 patients (45%). The incidence was very high in MNGIE (100%), MELAS (92%) and MERRF (69%), whilst 28% of PEO patients had evidence of peripheral involvement. The most frequent abnormality was a sensory axonal neuropathy found in 32/49 patients (65%). A sensory-motor axonal neuropathy was instead detected in 16% of the patients and sensory-motor axonal demyelinating neuropathy in 16%. Finally one Leigh patient had a motor axonal neuropathy. It is interesting to note that the great majority had preserved tendon reflexes and no sensory disturbances.
  
  
  
  In conclusion, peripheral involvement in MD is frequent even if often mild or asymptomatic. The correct identification and characterization of peripheral neuropathy through electrophysiological studies represents another tile in the challenge of MD diagnosis.
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Luigetti
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Sauchelli
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Primiano
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Cuccagna
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Bernardo
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Lo Monaco
authors.affiliation: Department of Geriatrics, Neurosciences and Orthopedics, Institute of Neurology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Servidei
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001369:Axons / Q000473:pathology / Q000502:physiology; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000473:pathology / Q000503:physiopathology; D008875:Middle Aged; D008928:Mitochondria / Q000235:genetics; D028361:Mitochondrial Diseases / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D010523:Peripheral Nervous System Diseases / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D013577:Syndrome; D055815:Young Adult
keywords: MELAS; MERRF; MNGIE; PEO; mitochondrial diseases; nerve; peripheral neuropathy