Li Ping, Zhang Lijuan, Zhao Na, Xiong Qiuhong, Zhou Yong-An, Wu Changxin, Xiao Han
Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China.
Bluttransfusion, The Second Hospital, Shanxi Medical University, Taiyuan, China.
Front Genet. 2019 Feb 11;10:60. doi: 10.3389/fgene.2019.00060. eCollection 2019.
Fabry disease (FD) is a rare X-linked α-galactosidase A () deficiency, resulting in progressive lysosomal accumulation of globotriaosylceramide (Gb3) in a variety of cell types. Here, we report a novel splicing mutation (c.801 + 1G > A) that results in alternative splicing in of a FD patient with variable phenotypic presentations of renal involvement. Sequencing of the RT-PCR products from the patient's blood sample reveals a 36-nucleotide (nt) insertion exists at the junction between exons 5 and 6 of the cDNA. Splicing assay indicates that the mutated minigene produces an alternatively spliced transcript which causes a frameshift resulting in an early termination of protein expression. Immunofluorescence shows puncta in cytoplasm for mutated whereas uniform staining small dots evenly distributed inside cytoplasm for wild type in transfected HeLa cells. The increased senescence and decreased GLA enzyme activity suggest that the abnormalities might be due to the altered localization which further might result from the lack of the C-terminal end of GLA. Our study reveals the pathogenesis of splicing mutation c.801 + 1G > A to FD and provides scientific foundation for accurate diagnosis and precise medical intervention for FD.
法布里病（FD）是一种罕见的X连锁α-半乳糖苷酶A（）缺乏症，导致多种细胞类型中球三糖神经酰胺（Gb3）在溶酶体中进行性蓄积。在此，我们报告了一例FD患者的一种新型剪接突变（c.801 + 1G > A），该患者有肾脏受累的多种表型表现，此突变导致α-半乳糖苷酶A的剪接异常。对该患者血样的逆转录聚合酶链反应（RT-PCR）产物进行测序，结果显示在α-半乳糖苷酶A cDNA的外显子5和6之间的连接处存在一个36个核苷酸（nt）的插入。剪接分析表明，突变的小基因产生了一种选择性剪接的转录本，该转录本导致移码，从而导致蛋白质表达提前终止。免疫荧光显示，在转染的HeLa细胞中，突变型α-半乳糖苷酶A在细胞质中有斑点，而野生型α-半乳糖苷酶A在细胞质内均匀染色且小点均匀分布。衰老增加和α-半乳糖苷酶A酶活性降低表明，这些异常可能是由于定位改变所致，而定位改变可能进一步是由于缺乏α-半乳糖苷酶A的C末端所致。我们的研究揭示了剪接突变c.801 + 1G > A导致法布里病的发病机制，并为法布里病的准确诊断和精准医疗干预提供了科学依据。
