Type I spinal muscular atrophy and disease modifying treatments: a nationwide study in children born since 2016

Background: The advent of disease-modifying treatments (DMT) has changed natural history in 5q Spinal muscular atrophy (SMA). The aim of this study was to report survival and functional aspects in all the Italian type I children born since 2016. Methods: The study included all symptomatic children with type I SMA born since January 1st, 2016, when DMTs became available in Italy. All the Italian SMA referral centers provided data on survival and motor, respiratory, and nutritional status. To compare survival rate pre and post DMTs approval, we also included similar data from SMA I patients born between January 1st, 2010, and December 31st, 2015. A two-proportion z-test was conducted to compare the two cohorts. The significance level was set at p <.05. Findings: 241 infants (98%) had type I SMA. Mean follow-up was 3.48 years (SD 2.33). Among type I patients, 42/241 did not survive (25 untreated), while 199 were alive at last follow-up (all treated; mean treatment age 0.6 years), with 25 needing >16 h/day ventilation or tracheostomy with continuous invasive ventilation. 130 of the 199 survivors (65%) achieved independent sitting, and 175 (87.9%) did not require tube feeding. Interpretation: Our study provides a picture of the ‘new natural history’ of type I SMA, confirming the impact of the new therapies on the progression of type I with longer survival r and has better motor, respiratory and nutritional. Funding: This research was partially funded by grants from the Italian Ministry of Health.