MBNL1 is a member of the muscleblind protein family which was initially described in Drosophila melanogaster. MBNL1 is a crucial protein involved in the regulation of pre-mRNA splicing, which is essential for the proper expression of genes. This 370 amino acid protein is predominantly expressed in various tissues, including skeletal muscle, prostate, lung, heart, small intestine, ovary, and placenta, highlighting its significance in diverse biological processes. MBNL1 plays a vital role in the splicing of pre-mRNAs by interacting with other splicing factors, thereby influencing the inclusion or exclusion of specific exons. Notably, MBNL1 and its homolog MBNL2 are implicated in myotonic dystrophy types 1 and 2, as MBNL1 localizes to nuclear foci formed by expanded CUG repeats, suggesting that the accumulation of mutant RNA in the nucleus contributes to the pathogenesis of these disorders.