The early therapeutic intervention can change the natural course in spinal muscular atrophy type 1

*Correspondence: [e-mail].

Abstract

Case Presentation: We'll present two cases of spinal muscular atrophy type 1 (SMA), in female patients, with different outcomes. Both had onset of symptoms within 3 m. (months) of life, with myofasciculation of the tongue, hypotonia/weakness/progressive muscle atrophy, with genetic testing revealing a homozygous deletion of exon 7/8 of the SMN1 gene and two copies of the SMN2 gene. In the first case, early diagnosis was possible due to the family history, and the chorionic villus sampling and PCR test were performed in utero. Treatment with nusinersen started at 35 days of life, followed by the application of zolgensma at 10 m. At 5 m., despite showing signs of respiratory and bulbar impairment (sweating, snoring, signs of dyspnea, occasional choking), requiring BIPAP, there were only 3 respiratory events up to 11 m., without serious complications. In addition, he presented progressive motor skills, with improvement in limb movement, reaching the maximum motor milestone of sitting without support at 11 m., with increasing scores on the CHOP INTEND (CI) scale: 22/64-3 days, 39/64-3 m., 48/64-5 m. and 60/64-11 m. In the second case, the diagnosis was made late, at 8 m. of life. At this stage, the patient already had severe symptoms, such as severe hypotonia, signs of bulbar dysfunction (absence of cough reflex, sialorrhea) and respiratory failure (tachypnea, dyspnea, bell-chest and paradoxical breathing), with a score on the CI scale of 20/64. Despite starting nusinersen 3 weeks after diagnosis, the patient had acceleration of the course of the disease, needing to orotracheal intubation and gastrostomy, with several unsuccessful extubation attempts, however, after the fourth dose of nusinersen, motor gains in limbs were observed, along with a 5-point increase on the CI scale (25/64).

Discussion: SMA, previously considered fatal, has had its scenario altered with the emergence of disease-modifying therapies. Studies show that early treatment increases survival and improves motor, respiratory, and bulbar function, albeit to varying degrees.

Final Comments: It is crucial to implement effective strategies for the early diagnosis and treatment of SMA, given its enormous familial, social, and economic impact. Feasible measures include neonatal screening tests, more specialized centers for rare diseases, and standardized scales to assess clinical progression and therapeutic response, aiming for a greater understanding of the disease, which will result in gains in quality of life and life expectancy.

 

MissingLinkText

Publication History

Article published online:
12 May 2025