PDF(Pubmed)
Abstract：
BACKGROUND: Alport syndrome (AS) is characterised by haematuria, proteinuria, a gradual decline in kidney function, hearing loss, and eye abnormalities. The disease is caused by mutations in COL4An (n = 3, 4, 5) that encodes 3-5 chains of type IV collagen in the glomerular basement membrane. AS has three genetic models: X-linked, autosomal recessive, and autosomal dominant. The most common type of AS is X-linked AS, which is caused by COL4A5.
METHODS: We enrolled children with renal insufficiency and a family history of kidney disorders. The proband was identified using whole-exome sequencing. Sanger sequencing was performed to verify the mutation site. Minigene technology was used to analyse the influence of mutant genes on pre-mRNA shearing, and the Iterative Threading ASSEmbly Refinement (I-TASSER) server was used to analyse the protein structure changes.
RESULTS: The proband, together with her mother and younger brother, displayed microscopic haematuria and proteinuria, Pathological examination revealed mesangial hyperplasia and sclerosis. A novel mutation (NM_000495.5 c.4298-8G > A) in the intron of the COL4A5 gene in the proband was discovered, which was also present in the proband\'s mother, brother, and grandmother. In vitro minigene expression experiments verified that the c.4298-8G > A mutation caused abnormal splicing, leading to the retention of six base pairs at the end of intron 46. The I-TASSER software predicted that the mutation affected the hydrogen-bonding structure of COL4A5 and the electrostatic potential on the surface of the protein molecules.
CONCLUSIONS: Based on the patient\'s clinical history and genetic traits, we conclude that the mutation at the splicing site c.4298-8G > A of the COL4A5 gene is highly probable to be the underlying cause within this particular family. This discovery expands the genetic spectrum and deepens our understanding of the molecular mechanisms underlying AS.
METHODS: We enrolled children with renal insufficiency and a family history of kidney disorders. The proband was identified using whole-exome sequencing. Sanger sequencing was performed to verify the mutation site. Minigene technology was used to analyse the influence of mutant genes on pre-mRNA shearing, and the Iterative Threading ASSEmbly Refinement (I-TASSER) server was used to analyse the protein structure changes.
RESULTS: The proband, together with her mother and younger brother, displayed microscopic haematuria and proteinuria, Pathological examination revealed mesangial hyperplasia and sclerosis. A novel mutation (NM_000495.5 c.4298-8G > A) in the intron of the COL4A5 gene in the proband was discovered, which was also present in the proband\'s mother, brother, and grandmother. In vitro minigene expression experiments verified that the c.4298-8G > A mutation caused abnormal splicing, leading to the retention of six base pairs at the end of intron 46. The I-TASSER software predicted that the mutation affected the hydrogen-bonding structure of COL4A5 and the electrostatic potential on the surface of the protein molecules.
CONCLUSIONS: Based on the patient\'s clinical history and genetic traits, we conclude that the mutation at the splicing site c.4298-8G > A of the COL4A5 gene is highly probable to be the underlying cause within this particular family. This discovery expands the genetic spectrum and deepens our understanding of the molecular mechanisms underlying AS.
摘要：
背景：Alport综合征（AS）的特征是血尿，蛋白尿,肾功能逐渐下降，听力损失,和眼睛异常。该疾病是由在肾小球基底膜中编码3-5个IV型胶原链的COL4An(n=3、4、5)中的突变引起的。AS有三种遗传模型：X连锁，常染色体隐性遗传,常染色体显性。最常见的AS类型是X-linkedAS，这是由COL4A5引起的。
方法：我们纳入了肾功能不全并有肾病家族史的儿童。使用全外显子组测序鉴定先证者。进行Sanger测序以验证突变位点。Minigene技术用于分析突变基因对前mRNA剪切的影响，并使用迭代线程鉴定（I-TASSER）服务器分析蛋白质结构的变化。
结果：先证者，和她的母亲和弟弟一起，显示镜下血尿和蛋白尿，病理检查发现肾小球系膜增生和硬化。在先证者COL4A5基因内含子中发现了一个新的突变(NM_000495.5c.4298-8G>A),这也出现在先证者的母亲身上，兄弟,和祖母。体外小基因表达实验证实c.4298-8G>A突变引起异常剪接,导致内含子46末端保留六个碱基对。I-TASSER软件预测突变会影响COL4A5的氢键结构和蛋白质分子表面的静电势。
结论：根据患者的临床病史和遗传特征，我们得出的结论是，COL4A5基因剪接位点c.4298-8G>A的突变很可能是该特定家族中的根本原因。这一发现扩展了遗传谱，加深了我们对AS分子机制的理解。
方法：我们纳入了肾功能不全并有肾病家族史的儿童。使用全外显子组测序鉴定先证者。进行Sanger测序以验证突变位点。Minigene技术用于分析突变基因对前mRNA剪切的影响，并使用迭代线程鉴定（I-TASSER）服务器分析蛋白质结构的变化。
结果：先证者，和她的母亲和弟弟一起，显示镜下血尿和蛋白尿，病理检查发现肾小球系膜增生和硬化。在先证者COL4A5基因内含子中发现了一个新的突变(NM_000495.5c.4298-8G>A),这也出现在先证者的母亲身上，兄弟,和祖母。体外小基因表达实验证实c.4298-8G>A突变引起异常剪接,导致内含子46末端保留六个碱基对。I-TASSER软件预测突变会影响COL4A5的氢键结构和蛋白质分子表面的静电势。
结论：根据患者的临床病史和遗传特征，我们得出的结论是，COL4A5基因剪接位点c.4298-8G>A的突变很可能是该特定家族中的根本原因。这一发现扩展了遗传谱，加深了我们对AS分子机制的理解。
