Author response: Discrepancy in redetermination of SMN2 copy numbers in children with SMA

We thank Dangouloff et al. for their comments on our clinical/scientific note.1 They compared the SMN2 copies in 35 SMA patients using 2 different MPLA kits: SALSA MLPA kit P021-A2 and P021-B1 (the latter recognizes each SMN exon; launched Dec. 2018).2 Three controls with 2 SMN1 or the cell line SD082 with 2 SMN1 and 2 SMN2 were used for normalization. Only 31% of patients showed identical SMN2 copies.