The following visits (V3, V4), reflecting a continuous 6 months treatment with Nusinersen, showed no further change of TSP4 in CSF derived from pediatric SMA patients under treatment (NDC: 70.52 ± 25.9, V1:32.41 ± 8.4, V2: 51.43 ± 22.1, V3: 53.82 ± 21.1, V4: 42.17 ± 21.7 pg/ml, Fig. 3a). Here, THBS4 is linked to proximal spinal muscular atrophy.