Double heterozygosity for a novel missense mutation of Ile304 to Asn in addition to the missense mutation His280 to Pro in the integrin β3 gene as a cause of the absence of platelet αIIbβ3 in Glanzmann's thrombasthenia
Double heterozygosity for a novel missense mutation of Ile304 to Asn in addition to the missense mutation His280 to Pro in the integrin β3 gene as a cause of the absence of platelet αIIbβ3 in Glanzmann's thrombasthenia
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DOI：
10.1111/j.1538-7836.2004.00990.x
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发表时间：
2005-01-01
影响因子：
10.4
通讯作者：
Tani, Y
中科院分区：
文献类型：
--
作者：
Tanaka, S;Hayashi, T;Tani, Y
背景资料：血小板无力症（GT）是一种遗传性出血性疾病，其特征是α（IIb）β（3）的表达或功能缺陷。目的：本研究的目的是确定遗传缺陷的GT患者。方法：采用流式细胞术和Western blotting检测α（IIb）β（3）的表达。我们分析了α（IIb）和β（3）的cDNA序列，并使用COS 7细胞进行转染实验，以确认特定的突变是GT病例的原因。结果：流式细胞仪分析和Western blotting显示α（IIb）β（3）的表达显著降低。对患者cDNA的序列分析表明，一个新的错义突变导致β（3）基因外显子6中Ile304（barC下的A（T））被Asn（barC下的A（A））取代。这是除了先前报道的外显子5中His280（barT下的C（A））到Pro（barT下的C（C））的错义突变之外的突变。发现β（3）中Ile3O4（barC下的A（T））到Asn（barC下的A（A））的错义突变是该GT病例的原因。这是因为使用COS 7细胞的转染实验表明，在β（3）中具有Asn304的α（IIb）β（3）在转染细胞的表面上不表达。此外，免疫沉淀分析表明，α（IIb）β（3）在β（3）中含有Asn304的转染COS 7细胞内不存在。结论：在这项研究中，我们描述了一个新的错义突变（A（T）下的barC下的barC下的A（A））在外显子6的位置1009，导致氨基酸取代（Ile304到Asn）在β（3），这是负责这个GT的情况下。
Background: Glanzmann's thrombasthenia (GT) is a hereditary bleeding disorder characterized by a defect in the expression or the function of alpha(IIb)beta(3). Objectives: The purpose of the present study was to identify genetic defects in a GT patient. Methods: The exp ression of alpha(IIb)beta(3) was determined by flow cytometric analysis and Western blotting. We analyzed the cDNA sequences of both alpha(IIb) and beta(3), and performed transfection experiments using COS7 cells to confirm that a specific mutation was responsible for the GT case. Results: Flow cytometric analysis and Western blotting showed remarkably reduced expression of alpha(IIb)beta(3). Sequence analysis of the patient's cDNA indicated a new missense mutation that led to the amino acid substitution of Ile304 (A (T) under barC) with Asn (A (A) under barC) in exon 6 of the beta(3) gene. This was in addition to the missense mutation of His280 (C (A) under barT) to Pro (C (C) under barT) in exon 5, which had been previously reported. The missense mutation of Ile3O4 (A (T) under barC) to Asn (A (A) under barC) in beta(3) was found to be responsible for this GT case. This was because transfection experiments using COS7 cells indicated that alpha(IIb)beta(3) possessing Asn304 in beta(3) was not expressed on the surface of the transfected cells. In addition, immunoprecipitation analysis demonstrated that alpha(IIb)beta(3) was absent inside the transfected COS7 cells possessing Asn304 in beta(3). Conclusion: In this study, we describe a new missense mutation (A (T) under barC to A (A) under barC) at position 1009 in exon 6 that leads to an amino acid substitution (Ile304 to Asn) in beta(3), which is responsible for this GT case.