A Novel α-Galactosidase A Splicing Mutation Predisposes to Fabry Disease
A Novel α-Galactosidase A Splicing Mutation Predisposes to Fabry Disease
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一种新型 α-半乳糖苷酶 A 剪接突变易患法布里病
DOI：
10.3389/fgene.2019.00060
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发表时间：
2019-02-11
影响因子：
3.7
通讯作者：
Xiao, Han
中科院分区：
文献类型：
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作者：
Li, Ping;Zhang, Lijuan;Xiao, Han
法布里病（FD）是一种罕见的x连锁α -半乳糖苷酶a （GLA）缺乏症，在多种细胞类型中导致globotriaosylceramide （Gb3）的进行性溶酶体积累。在这里，我们报告了一种新的剪接突变（c.801 + 1G > a），该突变导致患有肾脏病变的FD患者的GLA发生选择性剪接。对患者血液样本的RT-PCR产物测序显示，GLA cDNA外显子5和6之间的连接处存在36个核苷酸（nt）插入。剪接实验表明，突变的minigene产生一个选择性剪接的转录物，引起移码，导致蛋白表达的早期终止。在转染的HeLa细胞中，突变型GLA的免疫荧光显示细胞质中有点状斑点，而野生型GLA的免疫荧光显示细胞质中均匀分布有小点。衰老的增加和GLA酶活性的降低表明，这种异常可能是由于GLA的c端缺失导致的定位改变。本研究揭示了FD剪接突变c.801 + 1G > A的发病机制，为FD的准确诊断和精准医疗干预提供了科学依据。
Fabry disease (FD) is a rare X-linked alpha-galactosidase A (GLA) 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 GLA 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 GLA 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 GLA whereas uniform staining small dots evenly distributed inside cytoplasm for wild type GM 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.