Design Therapeutics, Inc. (Nasdaq: DSGN), a clinical-stage biotechnology company developing treatments for serious degenerative genetic diseases, today announced the initiation of patient dosing in its Phase 1 multiple-ascending dose (MAD) clinical trial evaluating DT-818 in adults with myotonic dystrophy type-1 (DM1). DT-818 is a GeneTAC® small molecule designed to selectively reduce transcription of the mutant DMPK allele and address the underlying cause of DM1.