Amyotrophic lateral sclerosis causes small fiber pathology

E. Dalla Bella, R. Lombardi, C. Porretta-Serapiglia, C. Ciano, C. Gellera, V. Pensato, D. Cazzato, G. Lauria

Research output: Contribution to journalArticlepeer-review


Background and purpose: Our aim was to address the correlation between small fiber loss and amyotrophic lateral sclerosis (ALS) for disease onset, phenotype, genotype, duration, severity and sensory findings. Methods: Consecutive patients referred for suspected ALS were screened. Exclusion criteria were possible ALS and previous diagnosis or known risk factors for small fiber neuropathies. A sural nerve conduction study (NCS) was bilaterally recorded. The ALS functional rating scale revised was administered and loss of functions were calculated using the Milano-Torino staging (MITOS) system. Sensory symptoms and signs were recorded. Genetic analysis was performed by the next-generation sequencing approach. Skin biopsy was performed at the distal leg and intraepidermal nerve fiber (IENF) density was quantified in three non-consecutive sections following published guidelines. Findings were referred to age- and sex-adjusted normative values. Results: Fifty-seven patients including six with facial onset sensory and motor neuronopathy (FOSMN) were enrolled. Eight (15.7%) pure ALS patients and five (83%) FOSMN patients complained of sensory disturbances with different distributions. Sural NCS was normal in all except two patients. IENF density was reduced in 75.4% of pure ALS and 50% of FOSMN patients, without correlation with any disease features. IENF density was similarly reduced in bulbar (78.5%), flail limb (87.5%), pyramidal (100%), and spinal (68.2%) onset, as well as in genetic (83.3%) and sporadic (82%) ALS. There was no correlation with genotype, disease duration and severity. Conclusions: Intraepidermal nerve fiber loss is a feature of most ALS patients. It does not correlate with onset, phenotype, course and severity of the disease, and cannot be considered a clinical or prognostic biomarker.

Original languageEnglish
Pages (from-to)416-420
Number of pages5
JournalEuropean Journal of Neurology
Issue number2
Publication statusPublished - Feb 1 2016


  • Amyotrophic lateral disease
  • Intraepidermal nerve fiber density
  • Motor neuron disease
  • Neuropathic pain
  • Skin biopsy
  • Small fiber neuropathy

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology


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