GTR Home > Conditions/Phenotypes > Amyotrophic lateral sclerosis type 4

Disease characteristics

Excerpted from the GeneReview: Amyotrophic Lateral Sclerosis Overview
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease involving both upper motor neurons (UMN) and lower motor neurons (LMN). UMN signs include hyperreflexia, extensor plantar response, increased muscle tone, and weakness in a topographic representation. LMN signs include weakness, muscle wasting, hyporeflexia, muscle cramps, and fasciculations. Initial presentation varies. Affected individuals typically present with either asymmetric focal weakness of the extremities (stumbling or poor handgrip) or bulbar findings (dysarthria, dysphagia). Other findings may include muscle fasciculations, muscle cramps, and labile affect, but not necessarily mood. Regardless of initial symptoms, atrophy and weakness eventually affect other muscles. The mean age of onset is 56 years in individuals with no known family history and 46 years in individuals with more than one affected family member (familial ALS or FALS). Average disease duration is about three years, but it can vary significantly. Death usually results from compromise of the respiratory muscles.

Associated genes

Clinical features

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  • Babinski sign
  • Hyperreflexia
  • Difficulty walking
  • Distal muscle weakness
  • Degeneration of anterior horn cells
  • Pallor of dorsal columns of the spinal cord
  • Diffuse axonal swelling
  • Peripheral axonal degeneration
  • Pes cavus
  • Upper motor neuron abnormality
  • Clonus
  • Abnormality of the lower motor neuron
  • Amyotrophic lateral sclerosis
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