Mapping the deletion endpoints in individuals with 22q11.2 Deletion Syndrome by droplet digital PCR
Mapping the deletion endpoints in individuals with 22q11.2 Deletion Syndrome by droplet digital PCR
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DOI：
10.1186/s12881-014-0106-5
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发表时间：
2014-10-14
影响因子：
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通讯作者：
Tassone, Flora
中科院分区：
文献类型：
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作者：
Hwang, Vicki J.;Maar, Dianna;Tassone, Flora
背景资料：染色体22 q11.2缺失综合征（22 q11DS）是人类最常见的微缺失综合征，与许多认知、神经和精神疾病相关。大多数个体具有3 Mb缺失，而其他个体具有巢式1.5 Mb缺失，但也描述了罕见的非典型缺失。到目前为止，使用液滴数字PCR（ddPCR）的研究尚未进行系统地映射的染色体断裂点在个人与22q11DS，这将提供重要的基因型洞察观察到的各种表型在此syndrome.Methods：本研究使用ddPCR评估拷贝数（CN）的变化内的染色体22q11缺失区域，并允许映射的删除端点。我们使用了8个TaqMan检测散布在整个22q11.2的缺失区域，以表征22号染色体的缺失区域在80个人已知有22q11DS的FISH。采用10种EvaGreen方法对6例22号染色体22 q11DS非典型缺失个体进行了精细定位。结果：ddPCR检测结果显示，在22号染色体的不同区域，CN值无差异，证实了22 q11DS非典型缺失的存在，并确定了5个不同大小和位置的缺失。大多数参与者（n = 74）有3 Mb的大缺失，而3人有较小的1.5 Mb缺失，其余3人有不同大小的间质缺失。结论：成本越低，ddPCR为22q11区域的CN测量提供的快速执行和高可靠性和特异性构成了对其他方法产生的可变CN值的显著改进。技术. ddPCR方法提供缺失终点的高分辨率定位的能力可能导致鉴定单倍不足的基因，并在22q11DS的发病机制中发挥作用。最后，这种方法可以应用于整个基因组的其他微缺失的表征。
Background: Chromosome 22q11.2 deletion syndrome (22q11DS) is the most common human microdeletion syndrome and is associated with many cognitive, neurological and psychiatric disorders. The majority of individuals have a 3 Mb deletion while others have a nested 1.5 Mb deletion, but rare atypical deletions have also been described. To date, a study using droplet digital PCR (ddPCR) has not been conducted to systematically map the chromosomal breakpoints in individuals with 22q11DS, which would provide important genotypic insight into the various phenotypes observed in this syndrome.Methods: This study uses ddPCR to assess copy number (CN) changes within the chromosome 22q11 deletion region and allows the mapping of the deletion endpoints. We used eight TaqMan assays interspersed throughout the deleted region of 22q11.2 to characterize the deleted region of chromosome 22 in 80 individuals known to have 22q11DS by FISH. Ten EvaGreen assays were used for finer mapping of the six identified individuals with 22q11DS atypical deletions and covering different regions of chromosome 22.Results: ddPCR provided non-ambiguous CN measurements across the region, confirmed the presence of the deletion in the individuals screened, and led to the identification of five differently sized and located deletions. The majority of the participants (n = 74) had the large 3 Mb deletions, whereas three had the smaller 1.5 Mb deletions, and the remaining three had an interstitial deletion of different size.Conclusions: The lower cost, rapid execution and high reliability and specificity provided by ddPCR for CN measurements in the 22q11 region constitutes a significant improvement over the variable CN values generated by other technologies. The ability of the ddPCR approach, to provide a high resolution mapping of deletion endpoints may result in the identification of genes that are haplo-insufficient and play a role in the pathogenesis of 22q11DS. Finally, this methodology can be applied to the characterization of other microdeletions throughout the genome.