Objective: The aim of this study was to provide an overview of the clinical phenotypes associated with 4 SMN2 copies. Methods: Clinical phenotypes were analyzed in all the patients with 4 SMN2 copies as part of a nationwide effort including all the Italian pediatric and adult reference centers for spinal muscular atrophy (SMA). Results: The cohort includes 169 patients (102 men and 67 women) with confirmed 4 SMN2 copies (mean age at last follow-up = 36.9 ± 19 years). Six of the 169 patients were presymptomatic, 8 were classified as type II, 145 as type III (38 type IIIA and 107 type IIIB), and 8 as type IV. The remaining 2 patients were asymptomatic adults identified because of a familial case. The cross-sectional functional data showed a reduction of scores with increasing age. Over 35% of the type III and 25% of the type IV lost ambulation (mean age = 26.8 years ± 16.3 SD). The risk of loss of ambulation was significantly associated with SMA type (p < 0.0001), with patients with IIIB and IV less likely to lose ambulation compared to type IIIA. There was an overall gender effect with a smaller number of women and a lower risk for women to lose ambulation. This was significant in the adult (p = 0.009) but not in the pediatric cohort (p = 0.43). Interpretation: Our results expand the existing literature on natural history of 4 SMN2 copies confirming the variability of phenotypes in untreated patients, ranging from type II to type IV and an overall reduction of functional scores with increasing age. ANN NEUROL 2023;94:1126–1135.
Clinical Phenotype of Pediatric and Adult Patients With Spinal Muscular Atrophy With Four SMN2 Copies: Are They Really All Stable? / Ricci, M.; Cicala, G.; Capasso, A.; Coratti, G.; Fiori, S.; Cutrona, C.; D'Amico, A.; Sansone, V. A.; Bruno, C.; Messina, S.; Mongini, T.; Coccia, M.; Siciliano, G.; Pegoraro, E.; Masson, R.; Filosto, M.; Comi, G. P.; Corti, S.; Ronchi, D.; Maggi, L.; D'Angelo, M. G.; Vacchiano, V.; Ticci, C.; Ruggiero, L.; Verriello, L.; Ricci, F. S.; Berardinelli, A. L.; Maioli, M. A.; Garibaldi, M.; Nigro, V.; Previtali, S. C.; Pera, M. C.; Tizzano, E.; Pane, M.; Tiziano, F. D.; Mercuri, E.. - In: ANNALS OF NEUROLOGY. - ISSN 0364-5134. - 94:6(2023), pp. 1126-1135. [10.1002/ana.26788]
Clinical Phenotype of Pediatric and Adult Patients With Spinal Muscular Atrophy With Four SMN2 Copies: Are They Really All Stable?
Pera M. C.;
2023-01-01
Abstract
Objective: The aim of this study was to provide an overview of the clinical phenotypes associated with 4 SMN2 copies. Methods: Clinical phenotypes were analyzed in all the patients with 4 SMN2 copies as part of a nationwide effort including all the Italian pediatric and adult reference centers for spinal muscular atrophy (SMA). Results: The cohort includes 169 patients (102 men and 67 women) with confirmed 4 SMN2 copies (mean age at last follow-up = 36.9 ± 19 years). Six of the 169 patients were presymptomatic, 8 were classified as type II, 145 as type III (38 type IIIA and 107 type IIIB), and 8 as type IV. The remaining 2 patients were asymptomatic adults identified because of a familial case. The cross-sectional functional data showed a reduction of scores with increasing age. Over 35% of the type III and 25% of the type IV lost ambulation (mean age = 26.8 years ± 16.3 SD). The risk of loss of ambulation was significantly associated with SMA type (p < 0.0001), with patients with IIIB and IV less likely to lose ambulation compared to type IIIA. There was an overall gender effect with a smaller number of women and a lower risk for women to lose ambulation. This was significant in the adult (p = 0.009) but not in the pediatric cohort (p = 0.43). Interpretation: Our results expand the existing literature on natural history of 4 SMN2 copies confirming the variability of phenotypes in untreated patients, ranging from type II to type IV and an overall reduction of functional scores with increasing age. ANN NEUROL 2023;94:1126–1135.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
