title: Blink reflex role in algorithmic genetic testing of inherited polyneuropathies.
abstract: In severely affected inherited polyneuropathy patients, primary demyelination can be difficult to determine by routine extremity limb nerve conduction studies (NCS). Blink reflexes may help classify severe polyneuropathies as either axonal or demyelinating. However, blink reflex studies have not been studied systematically in any genetically confirmed cohort.
  
  
  
  Patients with a genetic diagnosis who had undergone blink reflex testing and extremity NCS were identified retrospectively. Blink reflex R1 latency, extremity NCS, and severity were compared.
  
  
  
  We identified 26 demyelinating and 23 axonal, genetically confirmed cases, including 20 with PMP22 duplications. In 12 (25%), the ulnar CMAP amplitude was ≤0.5 mV making electrophysiological classification difficult. However, the R1-latency cutoff of >13 ms (demyelinating) robustly classified all patients regardless of severity.
  
  
  
  We show that blink reflex studies are reliable for identification of inherited demyelinating polyneuropathy regardless of severity and can facilitate algorithmic decisions in genetic testing. Muscle Nerve 55: 316-322, 2017.
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First Street, SW, Rochester, Minnesota, 55905, USA.|Department of Neurology, China-Japan Friendship Hospital, Beijing, China.
authors.forename: Wei
authors.identifier: 0000-0001-9708-1254
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First Street, SW, Rochester, Minnesota, 55905, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Litchy
authors.affiliation: Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Mandrekar
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First Street, SW, Rochester, Minnesota, 55905, USA.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Dyck
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First Street, SW, Rochester, Minnesota, 55905, USA.|Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.|Department of Medical Genetics, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Klein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D001767:Blinking / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004576:Electromyography; D005260:Female; D005820:Genetic Testing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D018993:Myelin P0 Protein / Q000235:genetics; D009185:Myelin Proteins / Q000235:genetics*; D009431:Neural Conduction / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D011115:Polyneuropathies / Q000235:genetics* / Q000503:physiopathology*; D012044:Regression Analysis; D014157:Transcription Factors / Q000235:genetics; D055815:Young Adult
chemical_list: C118738:LITAF protein, human; C560547:MPZ protein, human; D018993:Myelin P0 Protein; D009185:Myelin Proteins; D009687:Nuclear Proteins; C073687:PMP22 protein, human; D014157:Transcription Factors
keywords: Charcot-Marie-Tooth disease; PMP22; blink reflex; demyelinating polyneuropathy; genetic testing; inherited polyneuropathy