Integrated DNA, cDNA, and protein studies in Becker muscular dystrophy show high exception to the reading frame rule
Integrated DNA, cDNA, and protein studies in Becker muscular dystrophy show high exception to the reading frame rule
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DOI：
10.1002/humu.20722
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发表时间：
2008-05-01
期刊：
影响因子：
3.9
通讯作者：
Hoffman, Eric P.
中科院分区：
文献类型：
--
作者：
Kesari, Akanchha;Pirra, Laura N.;Hoffman, Eric P.
贝克尔肌营养不良症（BMD）是x连锁杜氏肌营养不良症（DMD）的一种较轻的形式。在这里，我们报告了一项对75例患者的研究，这些患者的肌肉活检免疫印迹和/或免疫染色结果与BMD（异常肌营养不良蛋白）一致。我们利用基因组DNA （gDNA）上的多重连接依赖探针扩增（MLPA）来筛选所有79个外显子的缺失和重复。共有19例MLPA突变检测为阴性的患者在肌肉活检中使用dna -MLPA检测mRNA剪接异常。对mlpa阴性患者进行全cDNA测序。我们在66例（88%）患者中发现了致病突变。在突变阳性患者中，42例（64%）显示一个或多个外显子缺失，14例（21%）显示重复，10例（15%）显示通过dna - mlpa和测序研究检测到的各种突变。在这个BMD系列中，我们发现阅读帧规则的“例外”率很高（帧外BMD； 17/56的删除/重复；30%）。这在一定程度上可以解释为BMD患者中5'基因缺失的高发率（已知是例外的热点区域），以及由于复杂的剪接模式，其中一部分转录本显示比gDNA更大的缺失（外显子跳变）。将BMD的研究结果与先前发表的DMD数据进行比较，BMD患者具有更高的重复比例，不同的突变分布以及更高的阅读框规则例外。
Becker muscular dystrophy (BMD) is a milder form of X-linked Duchenne muscular dystrophy (DMD). Here, we report a study of 75 patients with immunoblot and/or immunostaining findings of muscle biopsy consistent with BMD (abnormal dystrophin). We utilized multiplex ligation dependent probe amplification (MLPA) on genomic DNA (gDNA) to screen all 79 exons for both deletions and duplications. A total of 19 patients testing negative for MLPA mutations were tested for mRNA splicing abnormalities using cDNA-MLPA on muscle biopsy. Complete cDNA sequencing was done on MLPA-negative patients. We identified disease-causing mutations in 66 (88%) of the patients. Of the mutation-positive patients, 42 (64%) showed deletions of one or more exons, 14 (21 %) showed duplications, and 10 (15%) showed various mutations detected by cDNA-MLPA and sequencing studies. We found a high rate of "exceptions" to the reading frame rule in this BMD series (out-of-frame BMD; 17/56 deletions/duplications; 30%). This was partly explained by the high incidence of 5' gene deletions in BMD patients (a region known to be a hotspot for exceptions), and due to complex splicing patterns in which a subset of transcripts showed deletions larger than gDNA (exon-skipping). Comparing our findings in BMD to previously published DMD data, BMD patients have higher proportions of duplications, a different distribution of mutations, and higher exception to the reading frame rule.