title: Late-onset lower motor neuronopathy: a new autosomal dominant disorder.
abstract: OBJECTIVE
  Characterization of a new type of late-onset autosomal dominant lower motor neuron disease.
  
  
  METHODS
  Patients from 2 families underwent detailed neurologic, electrophysiologic, muscle biopsy, and laboratory investigations. MRI of lower limbs was performed in selected patients. DNA samples from leukocytes were used for molecular genetic linkage studies.
  
  
  RESULTS
  First symptoms were muscle cramps and fasciculations after age 25-30, followed by a slowly progressive proximal and distal weakness without overt atrophy during the first decades of symptoms. Nerve conduction velocities were within normal range and EMG showed widespread neurogenic alterations. Muscle biopsy revealed characteristic neurogenic findings: fiber type grouping and group atrophy. MRI showed diffuse fatty-degenerative changes, marked in medial gastrocnemius.
  
  
  CONCLUSIONS
  Exactly the same clinical phenotype has not previously been described, and linkage studies showed exclusion of known chromosomal loci for hereditary motor neuropathies, suggesting the disease we report may represent a new disorder.
authors.affiliation: Department of Neurology, Turku University Hospital, PO Box 52, FIN-20521 Turku, Finland. mejoke@utu.fi
authors.forename: M
authors.initials: M
authors.lastname: Jokela
authors.forename: S
authors.initials: S
authors.lastname: Penttilä
authors.forename: S
authors.initials: S
authors.lastname: Huovinen
authors.forename: P
authors.initials: P
authors.lastname: Hackman
authors.forename: A M
authors.initials: AM
authors.lastname: Saukkonen
authors.forename: J
authors.initials: J
authors.lastname: Toivanen
authors.forename: B
authors.initials: B
authors.lastname: Udd
mesh_terms: D000328:Adult; D017668:Age of Onset; D025063:Chromosome Disorders / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D004576:Electromyography; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000473:pathology; D009133:Muscular Atrophy / Q000150:complications; D009431:Neural Conduction / Q000502:physiology; D010375:Pedigree; D010641:Phenotype