title: A case of neuromyotonia and axonal motor neuropathy: A report of a HINT1 mutation in the United States.
abstract: BACKGROUND
  HINT1 mutations cause an autosomal recessive distal hereditary motor axonal neuropathy with neuromyotonia. This is a case report of a HINT1 mutation in the United States.
  
  
  METHODS
  A 30-year-old man of Slovenian heritage and no significant family history presented with scoliosis as a child and later developed neuromyotonia and distal weakness. Electrodiagnostic testing revealed an axonal motor neuropathy and neuromyotonic discharges. Previous diagnostic work-up, including testing for Cx32, MPZ, PMP-22, NF-L, EGR2, CLCN1, DM1, DM2, SMN exon 7/8, emerin, LMNA, MPK, SCNA4, acid maltase gene, paraneoplastic disorder, and a sural nerve biopsy, was negative.
  
  
  RESULTS
  Genetic testing for a HINT1 mutation was performed and revealed a homozygous mutation at p.Arg37Pro.
  
  
  CONCLUSIONS
  This entity should be distinguished clinically and genetically from myotonic dystrophy and channelopathies with the clinical features of neuromyotonia and an axonal neuropathy. This case illustrates the importance of identifying the correct phenotype to avoid unnecessary and costly evaluations.
authors.affiliation: Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52246, USA.
authors.forename: Nivedita U
authors.initials: NU
authors.lastname: Jerath
authors.affiliation: Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52246, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Shy
authors.affiliation: Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52246, USA.
authors.forename: Tiffany
authors.initials: T
authors.lastname: Grider
authors.affiliation: Department of Neurology, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, Iowa, 52246, USA.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Gutmann
mesh_terms: D000328:Adult; D004568:Electrodiagnosis; D015417:Hereditary Sensory and Motor Neuropathy / Q000150:complications / Q000235:genetics*; D006801:Humans; D020386:Isaacs Syndrome / Q000150:complications / Q000235:genetics*; D008297:Male; D009154:Mutation / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D014481:United States
chemical_list: C063306:HINT1 protein, human; D009419:Nerve Tissue Proteins
keywords: EMG; HINT1; hereditary neuropathy; mutation; neurogenetics; neuromyotonia