Department of Pediatrics, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China.
Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530021, P.R. China.
Int J Mol Med. 2021 Mar;47(3). doi: 10.3892/ijmm.2021.4861. Epub 2021 Feb 4.
Bethlem myopathy (BM) is an autosomal dominant or autosomal recessive disorder and is usually associated with mutations in the collagen VI genes. In the present study, the pathogenicity of a novel splice‑site mutation was explored using RNA‑sequencing in a family with suspected BM, and a myopathy panel was performed in the proband. The genetic status of all family members was confirmed using Sanger sequencing. Clinical data and magnetic resonance imaging (MRI) features were also documented. analysis was performed to predict the effects of the splice mutation. RNA‑sequencing and reverse transcription (RT)‑PCR were used to assess aberrant splicing. Immunocytochemistry was conducted to measure collagen VI protein levels within the gastrocnemius and in cultured skin fibroblasts. The results revealed that three patients in the family shared a similar classic BM presentation. MRI revealed distinct patterns of fatty infiltration in the lower extremities. A novel splicing mutation c.736‑1G>C in the collagen α‑2 (VI) chain () gene was found in all three patients. analysis predicted that the mutation would destroy the normal splice acceptor site. RNA‑sequencing detected two abnormal splicing variants adjacent to the mutation site, and RT‑PCR confirmed the RNA‑sequencing findings. Furthermore, a defect in the collagen protein within cultured fibroblasts was detected using immunocytochemistry. The mutation c.736‑1G>C in the gene caused aberrant splicing and led to premature termination of protein translation. In conclusion, these findings may improve our knowledge of mutations of the gene associated with BM and demonstrated that RNA‑sequencing can be a powerful tool for finding the underlying mechanism of a disease‑causing mutations at a splice site.
贝氏肌病 (BM) 是一种常染色体显性或常染色体隐性疾病，通常与六型胶原基因的突变有关。在本研究中，通过对一个疑似 BM 的家系进行 RNA 测序，探讨了一种新的剪接位点突变的致病性，并对先证者进行了肌病panel 检测。所有家庭成员的遗传状况均通过 Sanger 测序确认。还记录了临床数据和磁共振成像 (MRI) 特征。进行了 分析以预测剪接突变的影响。进行 RNA 测序和逆转录 (RT)-PCR 以评估异常剪接。通过免疫细胞化学测量腓肠肌和培养的皮肤成纤维细胞内的六型胶原蛋白水平。结果表明，家系中的 3 位患者具有相似的典型 BM 表现。MRI 显示下肢有明显的脂肪浸润模式。在所有 3 位患者中均发现胶原 α-2(VI)链 ()基因中的新型剪接突变 c.736-1G>C。 分析预测该突变会破坏正常的剪接受体位点。RNA 测序检测到突变位点附近的两个异常剪接变体，RT-PCR 证实了 RNA 测序的结果。此外，通过免疫细胞化学检测到培养的成纤维细胞内的胶原蛋白存在缺陷。基因中的突变 c.736-1G>C 导致异常剪接，并导致蛋白翻译过早终止。总之，这些发现可能会提高我们对与 BM 相关的 基因突变的认识，并证明 RNA 测序可以成为寻找致病突变剪接位点潜在机制的有力工具。
