Hereditary spastic paraparesis in adults. A clinical and genetic perspective from Tuscany

Objective: Hereditary spastic paraparesis or paraplegias (HSPs) are a group of neurogenetic conditions with prominent involvement of the pyramidal tracts. Aim of this study is the clinical and molecular characterization of a cohort of patients with HSP. Moreover, we aim to study the minimum prevalence of HSP in our area and to propose a schematic diagnostic approach to HSP patients based on the available data from the literature.

Methods: Retrospective/perspective study on the subjects with clinical signs and symptoms indicative of pure or complicated HSP, in whom other possible diagnosis were excluded by appropriate neuroradiological, neurophysiologic and laboratory studies, who have been evaluated by the Neurogenetic Service of our Clinic in last two years (2011-2012).

Results: 45 patients were identified. The minimum prevalence of HSP in our area was of about 2.17-3.43/100,000. The SF-36 (quality of life) and SPRS (disease progression) scores were inversely related; the time-saving, four-stage scale of motor disability could predict the SPRS scores with a high statistical significance, and we encourage its use in HSP. Our study confirms SPG4 as the major cause of HSP. All SPG4 patients had a pure HSP phenotype, and the dominant inheritance was evident in the great majority of these subjects. SPG7 was the second genetic cause. Other genotypes were rarer (SPG10, SPG11, SPG17).

Conclusion: Exact molecular diagnosis will allow a more accurate patient counseling and, hopefully, will lead to specific, targeted, therapeutic options for these chronic, still incurable diseases.