Next, AS of sarcoplasmic/ER calcium ATPase 1 (SERCA1) and insulin receptor (INSR) transcripts, previously found to be defective for exon inclusion in DM1 myogenic cells,25 was analysed by qRT‐PCR in untreated and DOX‐treated DM1 cells, compared with CT. The gene discussed is ATP2A1; the disease is myotonic dystrophy type 1.