Similar disease progression in nonsense Duchenne muscular dystrophy boys as general natural history: Single Brazilian center 15 years registry view.

Duchenne muscular dystrophy is a progressive and fatal X-linked neuromuscular disease. Emergent disease-modifying therapy (DMT) in nonsense Duchenne muscular dystrophy (nmDMD) has brought new perspectives to slow down functional decline in this fatal disease. To investigate if there are differences in natural history between nmDMD and other genotypes, we described a retrospective cohort analysis of 25 nonsense mutation DMD (nmDMD) boys without disease-modifying therapy, aged between 1 and 22 years, over the last 15 years (2007-2022) in a single neuromuscular center in Rio de Janeiro and use published data on DMD natural history for comparison. Regarding prognostic factors, there were remarkable and statistically significant early loss of ambulation (at 9.1y ±2.1) and shortening of life expectancy (17.6y ±2.1) in our nmDMD group. Late acquisition of neurodevelopmental milestones and annual rates of decline in respiratory, cardiac, and timed motor function tests are the same between nmDMD patients with standard care and other DMD genotypes as described in the literature. Our data indicates the similarity of natural history and disease progression among DMD boys with nmDMD mutations compared to different mutations.