A pedigree with myotonic dystrophy:electrophysiological and genetic characteristics

HUANG Jing; LEI Qian; LEI Xiao-yang; YANG Xiao-min; WAN Xiang-hong; HE Dian

doi:10.3969/j.issn.1672-6731.2025.09.009

Abstract：Objective To summarize the clinical,electrophysiological and genetic characteristics of a pedigree with myotonic dystrophy(DM).Methods and Results The 25-year-old male proband exhibited an occult onset,characterized by a distinctive"hatchet face"and alopecia,limb muscle weakness,amyotrophy,and damages of various systems,including the endocrine system and heart damage.Notably,the third aunt,the fourth uncle and the first brother of proband also exhibited similar clinical symptoms.Gene detection revealed both the proband,his aunt and his cousin had CTG repeats exceeding 100 times in the DMPK gene.Electromyography(EMG)studies conducted on the proband,his aunt and his cousin showed the coexistence of myotonic potential and myogenic damage.In the proband,the amplitude of the motor nerve conduction velocity of the left common peroneal nerve was decreased with a slight reduction in velocity,while the sensory nerve conduction velocity was also slowed.The proband,his aunt and his cousin were diagnosed with myotonic dystrophy type 1(MD1).It was evident that the pedigree has myotonic dystrophy.Conclusions Myotonic dystrophy is a rare autosomal dominant inheritance disorder characterized by myasthenia,myotonia and amyotrophy,which affects multiple systems.The clinical manifestations of this disease are diverse and relatively uncommon.In clinical practice,it is crucial to pay attention to the patient's family history,clinical signs and electrophysiological data,with particular emphasis on the identification of myotonic potential.Gene detection is of great significance for the diagnosis and differential diagnosis of myotonic dystrophy.