遗传 ›› 2024, Vol. 46 ›› Issue (7): 570-580.doi: 10.16288/j.yczz.24-020

• 遗传资源 • 上一篇    下一篇

一例DMD基因Alu元件插入突变导致杜氏肌营养不良及其白发症状分析

李慧1,2(), 张如意3, 李长叶4, 张肖林4, 郑庆印1(), 刘秀珍5()   

  1. 1.山东滨州医学院特殊教育与康复学院,烟台 264003
    2.江苏盐城市第一人民医院康复科,盐城 224000
    3.山东滨州医学院附属医院麻醉科,滨州 256603
    4.山东滨州医学院附属医院耳鼻喉头颈外科,滨州 256603
    5.山东滨州医学院附属医院医学研究中心,滨州 256603
  • 收稿日期:2024-04-17 修回日期:2024-05-31 出版日期:2024-07-20 发布日期:2024-06-03
  • 通讯作者: 刘秀珍,博士,副教授,研究方向:遗传病及聋病的诊断与机制研究。E-mail: liuxiuzhen0704@126.com;郑庆印,博士,教授,研究方向:遗传病及聋病的诊断与机制研究。E-mail: 2363616842@qq.com
  • 作者简介:李慧,硕士研究生,主管技师,专业方向:听力与言语康复。E-mail: 1141607103@qq.com
  • 基金资助:
    山东省自然科学基金面上项目(ZR2023MH186);中央引导地方科技发展资金项目(YDZX2022008);滨州市农社领域科技创新政策引导计划项目(2023SHFZ036);滨州市农社领域科技创新政策引导计划项目(2023SHFZ037)

A case study of Duchenne muscular dystrophy caused by Alu element insertion in DMD gene and analysis of its gray-hair symptoms

Hui Li1,2(), Ruyi Zhang3, Changye Li4, Xiaolin Zhang4, Qingyin Zheng1(), Xiuzhen Liu5()   

  1. 1. College of Special Education and Rehabilitation, Shandong Binzhou Medical University, Yantai 264003, China
    2. Department of Rehabilitation, Jiangsu Yancheng First People's Hospital, Yancheng 224000, China
    3. Department of Anesthesiology, Affiliated Hospital of Shandong Binzhou Medical University, Binzhou 256603,China
    4. Department of Otolaryngology, Affiliated Hospital of Shandong Binzhou Medical University, Binzhou 256603,China
    5. Medical Research Center, Affiliated Hospital of Shandong Binzhou Medical University, Binzhou 256603, China
  • Received:2024-04-17 Revised:2024-05-31 Published:2024-07-20 Online:2024-06-03
  • Supported by:
    Shandong Provincial Natural Science Foundation Project(ZR2023MH186);Shandong Provincial Central Guide Local Science and Technology Development Fund Project(YDZX2022008);Binzhou Municipal Agricultural Community Science and Technology Innovation Policy Guidance Program(2023SHFZ036);Binzhou Municipal Agricultural Community Science and Technology Innovation Policy Guidance Program(2023SHFZ037)

摘要:

杜氏肌营养不良(Duchenne muscular dystrophy,DMD)是由DMD基因突变引起的抗肌萎缩蛋白缺乏的一种严重X连锁隐性遗传病,突变形式主要包括外显子缺失和重复、点突变、插入突变等,这些突变通过不同方式影响了抗肌萎缩蛋白的正常表达,最终导致疾病的发生。本研究报告了1例DMD基因第59号外显子(exon 59,E59)插入突变引起的DMD,该患儿相关生化指标明显异常,表现较为明显的DMD早期症状,并出现了多处白发。其母亲和姐姐为携带者,生化指标轻微异常,母亲有轻微临床症状,姐姐无临床症状。其他成员基因和身体状况正常。经测序和序列比对发现,该插入片段为AluYa5亚家族的Alu元件,该片段插入可产生两个终止密码子,末端含一段多聚腺苷酸尾(polyA)。为了解该插入突变对于DMD基因的影响以及与临床症状的关联,通过外显子剪接增强子(exonic splicing enhancer,ESE)预测发现,该插入并不影响E59的剪接,由此推测该插入序列会最终出现在DMD基因的mRNA序列中,插入序列中的2个终止子和polyA很可能会在翻译过程中发挥终止作用,不能产生有功能的抗肌萎缩蛋白,这可能是导致DMD发生的机制。另外该患儿除了典型的DMD症状外,还出现了过早白发症状。本研究首次报道了1例DMD基因编码区插入Alu元件导致的DMD,为研究Alu序列逆转座引发基因突变提供线索,同时扩展了对DMD基因突变的认识。

关键词: 杜氏肌营养不良, DMD基因, Alu元件, 插入突变, 白发

Abstract:

Duchenne muscular dystrophy (DMD) is a severe X-linked recessive genetic disorder caused by mutations in the DMD gene, which leads to a deficiency of the dystrophin protein. The main mutation types of this gene include exon deletions and duplications, point mutations, and insertions. These mutations disrupt the normal expression of dystrophin, ultimately leading to the disease. In this study, we reported a case of DMD caused by an insertion mutation in exon 59 (E59) of the DMD gene. The affected child exhibited significant abnormalities in related biochemical markers, early symptoms of DMD, and multiple gray hair. His mother and sister were carriers with slightly abnormal biochemical markers. The mother had mild clinical symptoms, while the sister had no clinical symptoms. Other family members were genetically and physically normal. Sequencing and sequence alignment revealed that the inserted fragment was an Alu element from the AluYa5 subfamily. This insertion produced two stop codons and a polyadenylate (polyA) tail. To understand the impact of this insertion on the DMD gene and its association with clinical symptoms, exonic splicing enhancer (ESE) prediction indicated that the insertion did not affect the splicing of E59. Therefore, we speculated that the insertion sequence would be present in the mRNA sequence of the DMD gene. The two stop codons and polyA tail likely terminate translation, preventing the production of functional dystrophin protein, which may be the mechanism leading to DMD. In addition to typical DMD symptoms, the child also exhibited premature graying of hair. This study reports, for the first time, a case of DMD caused by the insertion of an Alu element into the coding region of the DMD gene. This finding provides clues for studying gene mutations induced by Alu sequence insertion and expands the understanding of DMD gene mutations.

Key words: Duchenne muscular dystrophy, DMD, Alu element, insertion mutation, gray hair