Table 3

Clinical characteristics of classical and atypical phenotypes of ALS and other motor neuron disorders

UMN signLMN signAsymmetryDementiaEndemic fociAdditional features
Classical phenotypes
 Primary lateral sclerosis++/−
 Progressive bulbar palsy+++/−
 Progressive muscular atrophy+
Atypical phenotypes
 ALS-parkinsonism-dementia complex+++Kii (Japan), Guam (USA), West Papua (Indonesia)Can present as familial with different phenotypes within single pedigree
 Madras motor neuron disease+++/−Southern parts of IndiaCranial nerve involvement, particularly hearing loss
 Monomelic amyotrophy of upper limb/juvenile muscular atrophy of distal upper extremity++Japan, IndiaJuvenile onset, male dominance, non-progressive course
 Monomelic amyotrophy of lower limb++IndiaJuvenile onset, male dominance, non-progressive course
  • +, Typical characteristic; −, not a typical characteristic; +/−, may be a concurrent characteristic; ALS, amyotrophic lateral sclerosis; LMN, lower motor neuron; UMN, upper motor neuron.