Salvatore Rossi, Anna Rubegni, Vittorio Riso, Melissa Barghigiani, Maria Teresa Bassi, Roberta Battini, Enrico Bertini, Cristina Cereda, Ettore Cioffi, Chiara Criscuolo, Beatrice Dal Fabbro, Clemente Dato, Maria Grazia D'Angelo, Antonio Di Muzio, Luca Diamanti, Maria Teresa Dotti, Alessandro Filla, Valeria Gioiosa, Rocco Liguori, Andrea Martinuzzi, Roberto Massa, Andrea Mignarri, Rossana Moroni, Olimpia Musumeci, Francesco Nicita, Ilaria Orologio, Laura Orsi, Elena Pegoraro, Antonio Petrucci, Massimo Plumari, Ivana Ricca, Giovanni Rizzo, Silvia Romano, Roberto Rumore, Simone Sampaolo, Marina Scarlato, Marco Seri, Cristina Stefan, Giulia Straccia, Alessandra Tessa, Lorena Travaglini, Rosanna Trovato, Lucia Ulgheri, Giovanni Vazza, Antonio Orlacchio, Gabriella Silvestri, Filippo Maria Santorelli, Mariarosa Anna Beatrice Melone, Carlo Casali, 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., and 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.
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) and abnormal motor evoked potentials (MEPs) were also associated with increased likelihood of worse disability (SPATAX score>3).DiscussionThe SPAST-HSP phenotypic spectrum in Italian patients confirms a predominantly pure form of HSP with mild-to-moderate disability in 75% of cases, and slight prevalence of men, who appeared more severely affected. Early-onset cases with intellectual disability were more frequent among patients carrying missense SPAST variants, whereas patients with truncating variants showed a more complicated disease. Both longer DD and altered MEPs are associated with worse disability. Methods: A cross-sectional retrospective study with molecular and clinical data collected in an anonymized database was performed. Results: A 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%, withmen 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 presentedmore 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) and abnormalmotor evoked potentials (MEPs) were also associated with increased likelihood of worse disability (SPATAX score>3). Discussion The SPAST-HSP phenotypic spectrum in Italian patients confirms a predominantly pure form of HSP with mild-to-moderate disability in 75% of cases, and slight prevalence of men, who appeared more severely affected. Early-onset cases with intellectual disability were more frequent among patients carrying missense SPAST variants, whereas patients with truncating variants showed a more complicated disease. Both longer DD and altered MEPs are associated with worse disability.