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Primary lateral sclerosis

Synonym(s) Adult-onset PLS
Adult-onset primary lateral sclerosis
Prevalence 1-9 / 100 000
Inheritance Autosomal recessive
or Not applicable
Age of onset All ages
  • G12.2
MeSH -
  • 10036704


Primary lateral sclerosis (PLS) is an idiopathic non-familial neurodegenerative disorder of upper motor neurons, presenting as a slowly progressive pyramidal tract syndrome. The annual incidence and the prevalence of PLS are estimated to 1 in 1.000.000 and 10-20 in 1.000.000, respectively. Disease onset is usually between 40 and 60 years with spasticity in the legs. Onset in the pseudobulbar region with speech and swallowing disturbance is also possible. Ultimately, a tetrapyramidal syndrome develops, sometimes with marked pseudobulbar features (forced laughing and crying). Pringle criteria for PLS consist of adult onset of symptoms, a negative family history, normal findings of blood, urine and cerebrospinal fluid (CSF) tests, no abnormalities on EMG, and on brain and spinal cord MRI. PLS is considered to be a benign variant of Amyotrophic lateral sclerosis (ALS). The etiology is not known. Treatment of PLS is symptomatic and can involve prescription of antispasticity medication and rehabilitation. Life expectancy is normal.

Expert reviewer(s)

  • Dr Frans BRUGMAN
  • Pr John WOKKE

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