Clinical and Paraclinical Indicators of Motor System Impairment in Hereditary Spastic Paraplegia: A Pilot Study

PLoS One. 2016 Apr 14;11(4):e0153283. doi: 10.1371/journal.pone.0153283. eCollection 2016.

Abstract

Background: Hereditary spastic paraplegias (HSP) are a composite and genetically heterogeneous group of conditions mainly expressed by the impairment of the central motor system ("pure" forms). The involvement of other components of the central nervous system or of other systems is described in the "complicate" forms. The definition of an investigation protocol capable, by assembling clinical and paraclinical indicators to fully represent the extent of the motor system impairment, would help both the clinical handling of these conditions and contribute to our understanding of their pathogenesis.

Methods: We applied a clinical and paraclinical protocol which included tools exploring motor and non motor functioning, neurophysiology and MRI to a composite cohort of 70 molecularly defined HSP patients aged 3 to 65, to define for each indicator its significance in detailing the presence and the severity of the pathology.

Results: Clinically increased deep tendon reflexes and lower limb (LL) weakness are constant findings in all patients. The "complicated" forms are characterized by peripheral motor impairment, cognitive and cerebellar involvement. The Spastic Paraplegia Rating Scale efficiently reflects the severity of functional problems and correlates with disease duration. Neurophysiology consistently documents the impairment of the central motor pathway to the LLs. Nevertheless, the upper extremities and sensory system involvement is a frequent finding. MRI diffusion tensor imaging (DTI) highlighted a significant alteration of FA and MD. Combining the sampling of the various portion of the cortico-spinal tract (CST) DTI consistently discriminated patients from controls.

Conclusion: We propose a graded clinical and paraclinical protocol for HSP phenotype definition, indicating for each tool the discriminative and descriptive capacity. Our protocol applied to 9 different forms of HSP showed that the functional impairment often extends beyond the CST. The novel DTI approach may add significant elements in disease recognition, staging and mapping.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adolescent
  • Adult
  • Aged
  • Analysis of Variance
  • Cerebellum / physiopathology
  • Child
  • Child, Preschool
  • Cognition / physiology
  • Cohort Studies
  • Female
  • GTP-Binding Proteins / genetics
  • Humans
  • Lower Extremity / physiopathology*
  • Magnetic Resonance Imaging
  • Male
  • Membrane Proteins / genetics
  • Middle Aged
  • Mutation
  • Pilot Projects
  • Reflex, Stretch / physiology*
  • Spastic Paraplegia, Hereditary / diagnosis
  • Spastic Paraplegia, Hereditary / genetics
  • Spastic Paraplegia, Hereditary / physiopathology*
  • Spastin
  • Tendons / physiopathology*
  • Young Adult

Substances

  • Membrane Proteins
  • ATL1 protein, human
  • Adenosine Triphosphatases
  • GTP-Binding Proteins
  • Spastin
  • SPAST protein, human

Grants and funding

This work was supported by the Italian Ministry of health under the frame of E-Rare-2, the ERA-Net for Research on Rare Diseases" grant NEUROLIPID and grant n. RF-IEM-2006-365041, RC 2009 (1.6); 2010 (10.4); 2011 (10.3); 2012(10.2) and RC 2013 (4.7) to AM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.