Cognitive function in SMA patients with 2 or 3 SMN2 copies treated with SMN-modifying or gene addition therapy during the first year of life.

Background: Spinal muscular atrophy (SMA) is a neuromuscular disease, causing progressive muscle weakness due to loss of lower motoneurons. Since 2017, three therapies, two modifying gene transcription and one adding the defective gene, have been approved with comparable efficacy on motor outcome. Data on cognitive outcomes of treated SMA type 1 patients is limited.