| Contributors: |
Rossi S, Rubegni A, Riso V, Barghigiani M, Bassi MT, Battini R, Bertini E, Cereda C, Cioffi E, Criscuolo C, Dal Fabbro B, Dato C, D'Angelo MG, Di Muzio A, Diamanti L, Dotti MT, Filla A, Gioiosa V, Liguori R, Martinuzzi A, Massa R, Mignarri A, Moroni R, Musumeci O, Nicita F, Orologio I, Orsi L, Pegoraro E, Petrucci A, Plumari M, Ricca I, Rizzo G, Romano S, Rumore R, Sampaolo S, Scarlato M, Seri M, Stefan C, Straccia G, Tessa A, Travaglini L, Trovato R, Ulgheri L, Vazza G, Orlacchio A, Silvestri G, Santorelli FM, Melone MAB, Casali C. |
| Description: |
Background and Objectives: Hereditary spastic paraplegias (HSPs) are a group of inherited rare neurologic disorders characterized by length-dependent degeneration of the corticospinal tracts and dorsal columns, whose prominent clinical feature is represented by spastic gait. Spastic paraplegia type 4 (SPG4, SPAST-HSP) is the most common form. We present both clinical and molecular findings of a large cohort of patients, with the aim of (1) defining the clinical spectrum of SPAST-HSP in Italy; (2) describing their molecular features; and (3) assessing genotype-phenotype correlations to identify features associated with worse disability.MethodsA cross-sectional retrospective study with molecular and clinical data collected in an anonymized database was performed.ResultsA total of 723 Italian patients with SPAST-HSP (58% men) from 316 families, with a median age at onset of 35 years, were included. Penetrance was 97.8%, with men showing higher Spastic Paraplegia Rating Scale (SPRS) scores (19.67 ± 12.58 vs 16.15 ± 12.61, p = 0.009). In 26.6% of patients with SPAST-HSP, we observed a complicated phenotype, mainly including intellectual disability (8%), polyneuropathy (6.7%), and cognitive decline (6.5%). Late-onset cases seemed to progress more rapidly, and patients with a longer disease course displayed a more severe neurologic disability, with higher SPATAX (3.61 ± 1.46 vs 2.71 ± 1.20, p < 0.001) and SPRS scores (22.63 ± 11.81 vs 12.40 ± 8.83, p < 0.001). Overall, 186 different variants in the SPAST gene were recorded, of which 48 were novel. Patients with SPAST-HSP harboring missense variants displayed intellectual disability (14.5% vs 4.4%, p < 0.001) more frequently, whereas patients with truncating variants presented more commonly cognitive decline (9.7% vs 2.6%, p = 0.001), cerebral atrophy (11.2% vs 3.4%, p = 0.003), lower limb spasticity (61.5% vs 44.5%), urinary symptoms (50.0% vs 31.3%, p < 0.001), and sensorimotor polyneuropathy (11.1% vs 1.1%, p < 0.001). Increasing disease duration (DD) ... |