Although downregulation of Mbl in Drosophila cell cultures and neural tissue results in a significant decrease in circMbl levels (Ashwal-Fluss et al. 2014), depletion of MBNL1 in DM1 skeletal muscles leads to elevated levels of circRNAs, as demonstrated by two independent research groups (Czubak et al. 2019a, b; Voellenkle et al. 2019). This evidence concerns the gene MBNL1 and myotonic dystrophy type 1.