John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne NE1 3BZ, UK.
Genetics Department, Institut de Recerca Sant Pau (IR SANT PAU), Hospital de la Santa Creu i Sant Pau, Genetics and Microbiology Department, Universitat Autonoma de Barcelona, 08041 Barcelona, Spain.
Int J Mol Sci. 2024 Jul 16;25(14):7793. doi: 10.3390/ijms25147793.
Duchenne and Becker muscular dystrophies, caused by pathogenic variants in , are the most common inherited neuromuscular conditions in childhood. These diseases follow an X-linked recessive inheritance pattern, and mainly males are affected. The most prevalent pathogenic variants in the gene are copy number variants (CNVs), and most patients achieve their genetic diagnosis through Multiplex Ligation-dependent Probe Amplification (MLPA) or exome sequencing. Here, we investigated a female patient presenting with muscular dystrophy who remained genetically undiagnosed after MLPA and exome sequencing. RNA sequencing (RNAseq) from the patient's muscle biopsy identified an 85% reduction in expression compared to 116 muscle samples included in the cohort. A de novo balanced translocation between chromosome 17 and the X chromosome (t(X;17)(p21.1;q23.2)) disrupting the and genes was identified through trio whole genome sequencing (WGS). The combined analysis of RNAseq and WGS played a crucial role in the detection and characterisation of the disease-causing variant in this patient, who had been undiagnosed for over two decades. This case illustrates the diagnostic odyssey of female DMD patients with complex structural variants that are not detected by current panel or exome sequencing analysis.
杜氏肌营养不良症和贝克肌营养不良症是由 基因中的致病性变异引起的,是儿童中最常见的遗传性神经肌肉疾病。这些疾病遵循 X 连锁隐性遗传模式,主要影响男性。 基因中最常见的致病性变异是拷贝数变异(CNVs),大多数患者通过多重连接依赖性探针扩增(MLPA)或外显子组测序获得基因诊断。在这里,我们研究了一名表现为肌肉营养不良的女性患者,在 MLPA 和外显子组测序后仍未得到基因诊断。患者肌肉活检的 RNA 测序(RNAseq)显示与包括在队列中的 116 个肌肉样本相比, 表达减少了 85%。通过三体系列全基因组测序(WGS)鉴定到一条 17 号染色体和 X 染色体之间的新发平衡易位(t(X;17)(p21.1;q23.2)),该易位破坏了 和 基因。RNAseq 和 WGS 的综合分析在检测和特征化该患者的致病变异方面发挥了关键作用,该患者在过去二十年中一直未得到诊断。该病例说明了女性 DMD 患者的诊断难题,这些患者存在复杂的结构变异,目前的面板或外显子组测序分析无法检测到这些变异。