title: Leg amyotrophic diplegia: prevalence and pattern of weakness at US neuromuscular centers.
abstract: OBJECTIVE
  To identify the frequency of leg amyotrophic diplegia (LAD) at a US academic center, describe the pattern of weakness, and provide comparative data from 8 additional major US academic institutions.
  
  
  BACKGROUND
  LAD is a leg onset variant of progressive muscular atrophy (PMA). LAD weakness is confined to the legs for at least 2 years, and there are no upper motor neuron signs.
  
  
  METHODS
  We present a retrospective chart review of 24 patients with the LAD presentation from the University of Kansas Medical Center ( n = 8 cases) and from 8 US academic institutions (n = 16 cases).
  
  
  RESULTS
  Of the 318 subjects identified in the University of Kansas Medical Center Neuromuscular Research Database, 82% (260 subjects) had amyotrophic lateral sclerosis (ALS), 1.9% (6) had familial ALS, 6.6% (21) had primary lateral sclerosis, and 9.2% (29) had lower motor neuron (LMN) disease. Of these 29 cases, 16 had PMA, 5 had brachial amyotrophic diplegia, while 8 had LAD. The mean LAD age of onset was 58 years with a male/female ratio of 3/1. Onset was asymmetric in 7/8. We identified a pelviperoneal pattern of weakness (sparing of knee extension and/or ankle plantar flexion) in 4 cases and distal predominant weakness in 3 cases. All patients had electrodiagnostic findings consistent with motor neuron disease confined to the lower extremities. We present LAD disease duration and survival data from 8 major academic neuromuscular centers. At last follow-up, weakness progressed to involve the arms in 6/24 LAD cases and of these 6 cases, 2 patients died from progression to typical ALS. From onset of symptoms, mean survival in LAD is 87 months, with 92% of cases being alive.
  
  
  CONCLUSIONS
  The natural history of LAD differs from typical forms of ALS and PMA. LAD is a slowly progressive disorder that accounts for a fourth of LMN disease cases. An asymmetric pelviperoneal pattern of weakness should heighten the suspicion for LAD.
authors: Department of Neurology, the University of Kansas Medical Center, Kansascity, KS, USA. mdimachkie@kumc.edu
authors: Mazen M
authors: MM
authors: Dimachkie
authors: Iryna M
authors: IM
authors: Muzyka
authors: Jonathan S
authors: JS
authors: Katz
authors: Carlayne
authors: C
authors: Jackson
authors: Yunxia
authors: Y
authors: Wang
authors: April L
authors: AL
authors: McVey
authors: Arthur
authors: A
authors: Dick
authors: Mamatha
authors: M
authors: Pasnoor
authors: M Tahseen
authors: MT
authors: Mozaffar
authors: Z
authors: Z
authors: Xiao-Song
authors: John T
authors: JT
authors: Kissel
authors: E
authors: E
authors: Ensrud
authors: Jeffrey
authors: J
authors: Rosenfeld
authors: Richard J
authors: RJ
authors: Barohn
mesh_terms: D000046:Academic Medical Centers; D017668:Age of Onset; D018450:Disease Progression; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D009134:Muscular Atrophy, Spinal / Q000453:epidemiology*; D015995:Prevalence; D012189:Retrospective Studies; D014481:United States
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