Adult Survival in SMA Type 1: A 23-Year Journey With Home Ventilation and Multidisciplinary Support

Spinal muscular atrophy (SMA) type 1 is a severe autosomal recessive neuromuscular disorder caused by loss-of-function variants in the SMN1 gene, typically leading to death within the first two years without intervention. Long-term survival is uncommon, especially in patients with the most severe genotypes, such as those carrying only one SMN2 copy, and is rarely reported in resource-limited settings. We describe a 23-year-old man from northeastern Brazil with SMA type 1 who has been fully ventilator-dependent since infancy. Early symptoms included hypotonia, weak cry, and paradoxical breathing, with acute respiratory failure at three months requiring tracheostomy and permanent invasive ventilation. Initial multiplex ligation-dependent probe amplification (MLPA) detected only a monoallelic SMN1 deletion, delaying genetic confirmation for over two decades. Whole-exome sequencing later revealed compound heterozygosity for a rare pathogenic SMN1 variant (c.770_780dup; p.Gly261Leufs*) and a deletion of the remaining allele, with only one SMN2 copy. Despite living in a resource-limited setting, the patient's home was adapted for long-term intensive care, with optimized ventilator settings, daily mechanically assisted cough, and trained caregivers. Over 23 years, he experienced only five respiratory infections, none requiring prolonged hospitalization. Neuroimaging in adulthood demonstrated bilateral global cortical atrophy and diffuse calvarial hyperostosis. Since starting nusinersen therapy, his clinical condition has remained stable without respiratory decline. This case demonstrates that, with individualized and sustained multidisciplinary care, adults with SMA type 1 and the most severe genotype can achieve exceptional long-term survival and stability, even in resource-limited environments. This report underscores the importance of advanced genetic testing when initial results are inconclusive and shows that excellence in supportive care can improve outcomes in SMA. We also emphasize the need for psychological management and ethical considerations in the long-term care of individuals with SMA.