Genetics and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Henan Engineering Research Center for Gene Editing of Human Genetic Disease, Erqi District, Zhengzhou, China.
Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Research Institute of Nephrology, Zhengzhou University, Zhengzhou, China.
Mol Genet Genomic Med. 2019 Jun;7(6):e653. doi: 10.1002/mgg3.653. Epub 2019 Apr 9.
Alport syndrome (AS) is an inherited progressive renal disease caused by mutations in COL4A3, COL4A4, and COL4A5 genes. The large sizes of these genes and the absence of mutation hot spots have complicated mutational analysis by routine PCR-based approaches. In recent years, the development of next-generation sequencing (NGS) has made possible the time- and cost-effective and accurate analysis of the three genes in a single step.
Here, we analyze COL4A3, COL4A4, and COL4A5 simultaneously in 29 AS patients using NGS. Candidate mutations were validated by classic Sanger sequencing and Real-time PCR.
Twenty two new mutations and 10 known mutations were detected. Of those novel mutations, 18, 3, and 1 mutations were detected in COL4A5, COL4A4, and COL4A3, respectively. Twenty six patients showed X-linked inheritance, one showed autosomal recessive inheritance and two showed digenic inheritance (DI).
A comparison of the clinical manifestations caused by different types of mutations in COL4A5 suggested that large fragment mutations are relatively more severe than the other missense mutations and AS by some mutations may show inter- and intra-familial phenotypic variability. It is important to consider these transmission patterns in the clinical evaluation according to the results of genetic testing, especially for DI. Twenty two new mutations can expand the genotypic spectrum of AS.
Alport 综合征（AS）是一种遗传性进行性肾脏疾病，由 COL4A3、COL4A4 和 COL4A5 基因突变引起。这些基因的大小较大，且不存在突变热点，这使得常规基于 PCR 的方法进行突变分析变得复杂。近年来，下一代测序（NGS）的发展使得在单个步骤中同时分析这三个基因的时间和成本效益以及准确性成为可能。
在这里，我们使用 NGS 同时分析 29 例 AS 患者的 COL4A3、COL4A4 和 COL4A5。通过经典 Sanger 测序和实时 PCR 验证候选突变。
检测到 22 个新突变和 10 个已知突变。在这些新突变中，COL4A5、COL4A4 和 COL4A3 中分别检测到 18、3 和 1 个突变。26 例患者表现为 X 连锁遗传，1 例表现为常染色体隐性遗传，2 例表现为双基因遗传（DI）。
比较 COL4A5 中不同类型突变引起的临床表现表明，大片段突变比其他错义突变更严重，一些突变的 AS 可能表现出个体内和个体间的表型变异性。根据遗传检测结果，特别是对于 DI，在临床评估中考虑这些遗传模式非常重要。22 个新突变可以扩展 AS 的基因型谱。
