一例貌似强直性肌营养不良的脊肌萎缩症的临床、病理及基因诊断

摘要

目的 明确1例表型复杂的神经肌病患者的诊断.方法 对该患者进行电生理、病理和致病基因突变分析,并结合国内外文献进行总结.结果 该患者临床病理表现貌似强直性肌营养不良( myotonic dystrophy,DM).基因诊断未发现假肥大型肌营养不良(Duchenne/Becker muscular dystrophy,DMD/BMD)致病基因Dystrophin 21个外显子的缺失突变以及DM1型致病基因DMPK的(CTG)n和DM2型致病基因ZNF9的(CCTG)n的重复扩增突变,但发现脊肌萎缩症(spinal muscular atrophy,SMA)致病基因SMN第7和8外显子的纯合缺失突变.结论 报告1例极为罕见的临床病理表现特殊而经基因诊断确诊的SMA.SMA有明显的临床异质性,临床电生理和病理诊断有其局限性,确诊必须结合基因诊断.%Objective To investigate a patient featuring a complex neuromuscular disease phenotype.Methods A comprehensive analysis integrating clinical investigation, electrophysiological testing,pathological analysis and mutation screening was carried out.Results The patient has presented clinical and pathological manifestations mimicking Duchenne muscular dystrophy. However, genetic analysis has identified no deletion in 21 exons of Dystrophin gene,no pathologic expansion of CTG repeats in DMPK gene or CCTG repeats in ZFN9 gene.Instead,a homozygous deletion of exons 7 and 8 in SMN gene was discovered.Conclusion A rare case of spinal muscular atrophy (SMA) was verified by genetic diagnosis.SMA is a group of neuromuscular disorders with great phenotypic heterogeneity and sometimes cannot be diagnosed by clinical manifestations,electrophysiological and pathological changes alone.Genetic diagnosis has become indispensable for accurate diagnosis for patients suspected to have the disease.