Spectrum of Phenotypes in SMA Patients With 4 SMN2 Copies in the French Population

Background and Objectives: gene are insufficiently described, and presymptomatic treatment remains controversial. Methods: This is a cohort study that analyzed data from SMA patients with zero SMN1 and 4 SMN2 copies collected in the "Registre SMA France" to describe epidemiology, clinical presentation, and course. Results: = 0.01). Sixty-five percent of patients used a wheelchair. Scoliosis surgery and ventilation were required in less than 15%. Discussion: copies in the French population show an onset during childhood and a progressive course with absence or loss of ambulation before adulthood. Presymptomatic treatment seems an acceptable option to consider, although identification of individual pejorative markers of early or severe phenotypes would allow more targeted approaches. Our results and literature suggest a gender effect in this population. Trial Registration Information: NCT04177134.