Raw data plots for discordant SMNCNC call. MPLA called 3 CNs for SMN1 in sample LP6005947‐DNA_D01, whereas SMNCNC called 2 CNs for SMN1. Closer inspection revealed MLPA to be correct. (A) Raw CN of full length SMN1 estimated by exon 7 and 8, histogram indicating the estimated CN of a large control cohort, vertical blue line indicates the discordant sample. (B) SMN1 and SMN2 raw CN values at the 8 loci used to determine the consensus CN. (C) SMN1 and SMN2 CN normalized against coverage depth at the 8 loci. (D) Scatterplot of the raw CN calls by MLPA, on the x‐axis raw CN for SMN1, and on the y‐axis raw CN for SMN2, discordant sample indicated with a line. (E) Scatter plot of the raw CN calls by SMNCNC, on the x‐axis raw CN for SMN1, and on the y‐axis raw CN for SMN2, discordant sample indicated with a line. CN = copy number; MLPA = multiplexed ligation‐dependent probe amplification; SMN = survival of motor neuron; SMNCNC = SMNCopyNumberCaller; WGS = whole genome sequencing.