 The RNA from the expanded trinucleotide repeat region forms intranucleoplasmic hairpin loops due to the extensive hydrogen bonding between C-G base pairs, and it has been demonstrated that these sequester the splicing regulator MBNL1 to form distinctive foci.DM2 is caused by a defect of the "CNBP" gene on chromosome 3.The specific defect is a repeat of the cytosine-cytosine-thymine-guanosine (CCTG) tetranucleotide in the "CNBP" gene.