Progressive myotonic dystrophy is a group of muscle degenerative diseases caused by genetic defects, with progressively increasing muscle weakness and atrophy as the main clinical manifestations. Depending on the genetic defect, the clinical symptoms appear early or late, either as early as fetal life or in adulthood. As is known from the name of the disease, the course of myotonic dystrophy is generally progressive, but the rate of disease progression varies. What tests are needed to diagnose progressive myotonic dystrophy? 1, creatine phosphokinase (CK): significantly elevated, tens to hundreds of times the normal value. In the early stage of the disease or even the asymptomatic stage can appear significantly elevated. 2, electromyography: suggests myogenic damage. 3, muscle biopsy: suggests myotonic dystrophy-like changes, muscle fiber size varies, fatty connective tissue hyperplasia, visible muscle fiber necrosis and regeneration, muscle biopsy specimens can be seen in scattered eosinophilic hypertrophic muscle fibers, the lack of inflammatory cell infiltration. dystrophin immunohistochemical staining was negative. 4, DMD gene examination: DMD gene is one of the more massive human genes, including 79 exons. Types of gene mutations include deletions, duplications and point mutations. About 65% of Duchenne muscular dystrophy and about 85% of Becker-type muscular dystrophy are caused by deletion of one or more exons of the DMD gene; 6-10% of Duchenne and Becker muscular dystrophy are caused by duplication of one or more exons of the DMD gene. The classic multiplex PCR technique can detect approximately 98% of gene deletions. mLPA (multiplex ligation-dependent probe amplification) is currently the most commonly used method for the detection of all exon deletions and duplications. 5. Echocardiography and ECG: Children with a diagnosis of DMD should undergo regular cardiac investigations, including echocardiography and ECG, to assess cardiac function.