Abstract:

Objective To analyze the clinical characteristics and gene variation of Duchenne muscular dystrophy （DMD），and to provide a reference for clinical diagnosis，treatment and genetic counseling. Methods The clinical characteristics of 15 children with suspected pseudohypertrophic muscular dystrophy in the First Affiliated Hospital of Henan University of Science and Technology from July 2019 to July 2021 were analyzed retrospectively，and the gene variation characteristics were analyzed by multiplex ligation-dependent probe amplification（MLPA） and whole-exome sequencing （WES）. The variation sites were analyzed by bioinformatics. Results Among the 15 patients，14 patients had variations in DMD gene，including 12 large exon deletions and 2 point mutations [c.2168+1G>T and c.9917_9923del（p.Thr3306Serfs*22）]. The identified large deletions were involved in 11 different regions of DMD gene，of which 8 caused frameshifts，2 caused in-frame deletions and 1 caused loss of whole protein expression. The 14 patients with DMD gene variations had the characteristics of abnormally increased enzymes and myogenic damage，and they were diagnosed as DMD. In addition，1 patient with negative result from DMD gene detection had compound heterozygous variation of LAMA2 gene [c.819+1G>A and c.1884G>A（p.Glu628Glu）]，and the subject was diagnosed with limb-girdle muscular dystrophy （LGMD）. Conclusions Clinical attention should be paid to the differential diagnosis of DMD，Becker muscular dystrophy and LGMD. For children with progressive muscular dystrophy combined with creatine kinase and other enzymatic change and myogenic damage，MLPA is recommended to detect the copy number of DMD gene. Next-generation sequencing should be used to further analyze the genetic etiology.

Key words: Duchenne muscular dystrophy, Multiplex ligation-dependent probe amplification, Whole-exome sequencing, Genetic diagnosis