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Abstract：
BACKGROUND: Both Pierson syndrome (PS) and isolated nephrotic syndrome can be caused by LAMB2 biallelic pathogenic variants. Only 15 causative splicing variants in the LAMB2 gene have been reported. However, the pathogenicity of most of these variants has not been verified, which may lead to incorrect interpretation of the functional consequence of these variants.
METHODS: Using high-throughput DNA sequencing and Sanger sequencing, we detected variants in a female with clinically suspected PS. A minigene splicing assay was performed to assess the effect of LAMB2 intron 20 c.2885-9C>A on RNA splicing. We also performed the immunohistochemical analysis of laminin beta-2 in kidney tissues.
RESULTS: Two novel LAMB2 heteroallelic variants were found: a paternally inherited variant c.2885-9C>A in intron 20 and a maternally inherited variant c. 3658C>T (p. (Gln1220Ter)). In vitro minigene assay showed that the variant c.2885-9C>A caused erroneous integration of a 7 bp sequence into intron 20. Immunohistochemical analysis revealed the absence of glomerular expression of laminin beta-2, the protein encoded by LAMB2.
CONCLUSIONS: We demonstrated the impact of a novel LAMB2 intronic variant on RNA splicing using the minigene assay firstly. Our results extend the mutational spectrum of LAMB2.
METHODS: Using high-throughput DNA sequencing and Sanger sequencing, we detected variants in a female with clinically suspected PS. A minigene splicing assay was performed to assess the effect of LAMB2 intron 20 c.2885-9C>A on RNA splicing. We also performed the immunohistochemical analysis of laminin beta-2 in kidney tissues.
RESULTS: Two novel LAMB2 heteroallelic variants were found: a paternally inherited variant c.2885-9C>A in intron 20 and a maternally inherited variant c. 3658C>T (p. (Gln1220Ter)). In vitro minigene assay showed that the variant c.2885-9C>A caused erroneous integration of a 7 bp sequence into intron 20. Immunohistochemical analysis revealed the absence of glomerular expression of laminin beta-2, the protein encoded by LAMB2.
CONCLUSIONS: We demonstrated the impact of a novel LAMB2 intronic variant on RNA splicing using the minigene assay firstly. Our results extend the mutational spectrum of LAMB2.
摘要：
背景：Pierson综合征（PS）和孤立性肾病综合征均可由LAMB2双等位基因致病变异引起。仅报道了LAMB2基因中的15种致病剪接变体。然而,大多数这些变异的致病性尚未得到证实，这可能导致对这些变体的功能后果的错误解释。
方法：使用高通量DNA测序和Sanger测序，我们在一名临床怀疑PS的女性中检测到变异。进行小基因剪接测定以评估LAMB2内含子20c.2885-9C>A对RNA剪接的影响。我们还对肾组织中的层粘连蛋白β-2进行了免疫组织化学分析。
结果：发现了两个新的LAMB2异等位基因变体：内含子20中的父系遗传变体c.2885-9C>A和母系遗传变体c。3658C>T（p。（Gln1220Ter）。体外小基因测定显示变体c.2885-9C>A导致7bp序列错误整合到内含子20中。免疫组织化学分析显示缺乏LAMB2编码的层粘连蛋白β-2的肾小球表达。
结论：我们首先使用小基因测定证明了新型LAMB2内含子变体对RNA剪接的影响。我们的结果扩展了LAMB2的突变谱。
方法：使用高通量DNA测序和Sanger测序，我们在一名临床怀疑PS的女性中检测到变异。进行小基因剪接测定以评估LAMB2内含子20c.2885-9C>A对RNA剪接的影响。我们还对肾组织中的层粘连蛋白β-2进行了免疫组织化学分析。
结果：发现了两个新的LAMB2异等位基因变体：内含子20中的父系遗传变体c.2885-9C>A和母系遗传变体c。3658C>T（p。（Gln1220Ter）。体外小基因测定显示变体c.2885-9C>A导致7bp序列错误整合到内含子20中。免疫组织化学分析显示缺乏LAMB2编码的层粘连蛋白β-2的肾小球表达。
结论：我们首先使用小基因测定证明了新型LAMB2内含子变体对RNA剪接的影响。我们的结果扩展了LAMB2的突变谱。
