Small fibre neuropathy in mitochondrial diseases explored with sudoscan. Issue 8 (August 2018)

• Record Type: Journal Article
• Authors: Luigetti, Marco; Primiano, Guido; Cuccagna, Cristina; Bernardo, Daniela; Sauchelli, Donato; Vollono, Catello; Servidei, Serenella
• Is Part Of: Clinical neurophysiology. Volume 129:Issue 8(2018:Aug.)
• Page Start: 1618
• Page End: 1623
• Publication Date: 2018-08
• Subjects: MDs mitochondrial diseases -- PEO progressive external ophthalmoplegia -- MELAS mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes -- MERRF myoclonic epilepsy with ragged-red fibres -- MIDD maternally inherited diabetes and deafness -- POLG1 polymerase gamma 1 -- TWINKLE TWINKLE mtDNA helicase -- DGUOK deoxyguanosine kinase -- ESC electrochemical skin conductance -- SSR sympathetic skin response -- NCS nerve conductions studies -- DML distal motor latency -- CMAP compound muscle action potential -- SNAP sensory nerve action potential; Mitochondrial diseases -- Small fibres -- Peripheral neuropathy -- Sudoscan -- MELAS -- MERRF -- PEO; Neurophysiology -- Periodicals; Electroencephalography -- Periodicals; Electromyography -- Periodicals; Neurology -- Periodicals; 612.8
• DOI: 10.1016/j.clinph.2018.04.755
• Languages: English
• ISSNs: 1388-2457

Abstract

Highlights: Very few data are reported about small fibres involvement in mitochondrial diseases. In progressive external ophthalmoplegia small fibre neuropathy may be a predictor of single mtDNA deletion. Small fibre neuropathy should be included among the possible features of mitochondrial diseases. Abstract: Objective: Polyneuropathy in mitochondrial diseases (MDs) is relatively common and widely investigated, but few data are instead reported about small fibres involvement. Methods: In order to investigate the involvement of small fibres in MDs we performed extensive neurophysiological test (nerve conduction studies; sympathetic skin response; sudoscan) in 27 patients with genetic diagnosis of MD (7 m.3243A > G; 4 m.8344A > G; 9 single mtDNA deletion; 7 multiple mtDNA deletions). Results: NCS showed a polyneuropathy in 11/27 cases (41%). The incidence was very high in POLG1 (100%), m.8344A > G (75%) and m.3243A > G (43%), while only 11% of patients with single deletion had evidence of large fibres involvement. Sympathetic skin response was abnormal only in three patients (one progressive external ophthalmoplegia with single mtDNA deletion; one patient with m.3243A > G mutation; one patient with POLG1 mutation). Sudoscan revealed the presence of an autonomic small fibres dysfunction in 9/27 cases (33%), most of them (7/9) carrying a single mtDNA deletion. Sudoscan data were also confirmed in a sub-group of patients by laser evoked potentials study. Considering only patients with single mtDNA deletion 7/9 (78%) showed abnormal results at sudoscan. Conclusions: Small fibre neuropathy is another feature to investigate in mitochondrial diseases and seems specifically associated with the presence of single mtDNA deletion. Significance: The correct identification through specific neurophysiological tests of small fibres involvement in MDs represents another tile in this challenging diagnosis.