SMN2 Copy Number Association with Spinal Muscular Atrophy Severity: Insights from Colombian Patients

Abstract

Background: Spinal muscular atrophy (SMA) is a genetic neurodegenerative disease primarily affecting paediatric patients, often leading to significant morbidity and mortality. Our principal objective is to describe the sociodemographic characteristics and evaluate the association between the number of SMN2 copies and SMA type in patients from the Colombian Foundation for Spinal Muscular Atrophy (FAMECOL) database. Methodology: An analytical cross-sectional study was conducted on 201 patients with a genetic diagnosis of SMA. Data were identified, extracted, and collected from patient records provided by FAMECOL as patients registered with the association, including 201 patients from April 2013 to April 2024, when the database was delivered. Qualitative variables were described using relative and absolute frequencies, while quantitative variables were described using central tendency and dispersion measures according to their distribution. The association between the SMA type and the SMN2 number of copies was assessed by Fisher’s exact test (1 to 5 copies). Results: Of the 201 patients studied, 42% were female (n = 85), and 58% were male (n = 116). The median age was 9 years (IQR 4–16 years). The median age at diagnosis was 9 years (IQR 4–16), varying by subgroup: 2, 7, 14, and 41.5 years for each type, respectively. A total of 25% patients were from Antioquia (n = 51). Eighty-nine per cent had gastrostomy (n = 18). The association between the two variables was statistically significant (p < 0.05). Conclusion: This study highlights SMA clinical variability and its association with the number of SMN2 copies, underscoring the importance of a personalised approach to diagnosing and managing this disease. The findings may guide more effective therapeutic strategies to improve patients’ quality of life.