Clinical follow-up of a child with spinal muscular atrophy after treatment with Nusinersena

*Correspondence: [e-mail].

Abstract

Case Presentation: Patient, female, 5 months old, born at term, of non-consanguineous parents, with a family history of a sibling with Spinal Muscular Atrophy (SMA) type 1. At birth, she realized a genetic test, with a positive result for SMA (homozygous deletion of the SMN1 gene). At 23 days old, she received the first intrathecal application of Nusinersena, with three subsequent applications at intervals of 14, 28 and 58 days. Before starting treatment, she underwent a clinical evaluation, presenting with 34 points on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) (0-64 points). After four applications of the drug, at approximately 5 months of age, the patient underwent a new evaluation, with 60 points on the CHOP INTEND, with all the expected developmental milestones for her age and, in relation to the symptoms of SMA, she presented only tongue fasciculations. At approximately 2 months of life, the patient developed bronchiolitis, which was managed on an outpatient basis, without the need for hospitalization.

Discussion: SMA is a rare autosomal recessive disease, caused by mutations or deletions in the SMN 1 gene, leading to degeneration of lower motor neurons and, consequently, atrophy and progressive muscle weakness. The disease is classified according to the age of onset of symptoms and the motor capacity shown, with type 1 the most common, in which symptoms begin before 6 months of life and there is usually a need for ventilatory support. Nusinersena is an antisense oligonucleotide recently approved for the treatment of SMA, which has been shown to provide increased survival without permanent ventilatory support in patients with type 1 SMA, and when treatment is established before the onset of symptoms, has provided near-normal motor development. The reported case presents a positive result in relation to the medication, since the patient obtained a high score on the CHOP INTEND after the applications, has been showing good motor neurodevelopment and, even with bronchiolitis, did not require ventilatory intervention.

Final Comments: Early initiation of treatment with Nusinersena has been shown to improve survival in patients with SMA, as well as preserving their motor skills. However, it is necessary to develop new studies to better understand these benefits, especially in the long term.

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Artikel online veröffentlicht:
12. Mai 2025