title: Spinocerebellar ataxia type 7: a neurodegenerative disorder with peripheral neuropathy.
abstract: BACKGROUND
  Autosomal dominant spinocerebellar ataxias (SCA) are a group of inherited neurodegenerative disorders that typically show peripheral neuropathy. SCA7 is one of the rarest forms of SCA (<1/100,000 individuals). However, the disease shows a prevalence of ∼800/100,000 inhabitants in certain regions of Mexico. This low global prevalence may explain, at least in part, the isolated anecdotal and limited clinical data regarding peripheral neuropathy in SCA7 patients.
  
  
  OBJECTIVE
  To assess sensory and motor peripheral nerve action potentials in an SCA7 patients group and in healthy volunteers, and subsequently correlate the electrophysiological findings with clinical and genetic features.
  
  
  METHODS
  We enrolled in our study, 13 symptomatic SCA7 patients with a confirmed molecular and clinical diagnosis, and 19 healthy volunteers as the control group. Nerve conduction studies were carried out using standard electromyography recording methods. The sensory and motor latency, amplitude and conduction velocity were recorded in both experimental groups and analyzed using the Student's t-test.
  
  
  RESULTS
  SCA7 patients showed a significant prolongation of sensory nerve conduction latencies, as well as a decrease in sensory amplitudes. Decreases in motor amplitudes and peroneal conduction velocity were also observed. Finally, we found an association between CAG repeats and the severity of cerebellar and non-cerebellar symptoms with electrophysiological signs of demyelinization.
  
  
  CONCLUSIONS
  Our results reveal the existence of a critical sensorimotor peripheral neuropathy in SCA7 patients. Moreover, we show that using sensitive electrophysiological tools to evaluate nerve conduction can improve the diagnosis and design of therapeutic options based on pharmacological and rehabilitative strategies.
  
  
  CONCLUSIONS
  These findings demonstrate that SCA7 is a disease that globally affects the peripheral nervous system.
authors.affiliation: Centro de Rehabilitación e Inclusión Social de Veracruz, Xalapa, Mexico.
authors.forename: José
authors.initials: J
authors.lastname: Salas-Vargas
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Mancera-Gervacio
authors.forename: Luis
authors.initials: L
authors.lastname: Velázquez-Pérez
authors.forename: Roberto
authors.initials: R
authors.lastname: Rodrígez-Labrada
authors.forename: Emilio
authors.initials: E
authors.lastname: Martínez-Cruz
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Magaña
authors.forename: Alfredo
authors.initials: A
authors.lastname: Durand-Rivera
authors.forename: Oscar
authors.initials: O
authors.lastname: Hernández-Hernández
authors.forename: Bulmaro
authors.initials: B
authors.lastname: Cisneros
authors.forename: Rigoberto
authors.initials: R
authors.lastname: Gonzalez-Piña
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D010523:Peripheral Nervous System Diseases / Q000235:genetics* / Q000503:physiopathology; D020754:Spinocerebellar Ataxias / Q000150:complications* / Q000235:genetics / Q000503:physiopathology