Clinical Analysis of a Child with Myotonic Dystrophy Type 1 Misdiagnosed as Autism Spectrum Disorder

LV Shaoguang; LIU Fang; ZHAO Huidong; XU Jianfeng

doi:10.3969/j.issn.1002-3429.2025.08.003

Abstract：Objective To summarize the causes and preventive measures of myotonic dystrophy type1(DM1)misdi-agnosed as autism spectrum disorder(ASD).Methods The clinical data of a child with DM1 misdiagnosed as ASD in May 2021 were retrospectively analyzed.Results The girl,whose mother had minimal fetal movement during pregnancy,devel-oped a special facial feature with an inverted V-shaped upper lip after birth,delayed major motor development,activity intoler-ance,lack of speech,and reluctance to talk to others.She was diagnosed with autism in another hospital and received inter-mittent rehabilitation therapy,but the effect was not satisfactory.The routine examination of blood,urine and stool,liver and kidney function,thyroid function,46 kinds of inherited metabolic diseases,blood tandem mass spectrometry,urine meteoro-logical chromatography,chromosome karyotype analysis and heart color Doppler ultrasound were all normal.Multiplex ligation-dependent probe amplification(MLPA)+methylation test was negative for Prader-Willi syndrome and spinal muscular atro-phy.Genetic testing supported the diagnosis of DM1.The misdiagnosis lasted 1 year.After rehabilitation training for more than 3 years,the boy is now 6 years old with a good prognosis.Conclusion DM1 patients have various clinical manifesta-tions,such as behavior disorder,social withdrawal and other ASD-like symptoms.It is prone to misdiagnosis if the doctor has insufficient knowledge of the disease.Early misdiagnosis of DM1 can be reduced or avoided by strengthening clinicians'under-standing of DM1,taking medical history carefully,developing diagnostic thinking,and conducting genetic testing as early as possible.