Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Chair and Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, 60-781 Poznan, Poland.
Genomics. 2020 Sep;112(5):2937-2941. doi: 10.1016/j.ygeno.2020.05.003. Epub 2020 May 6.
To further assess the scale and level of parental somatic mosaicism, we queried the CMA database at Baylor Genetics. We selected 50 unrelated families where clinically relevant apparent de novo CNV-deletions were found in the affected probands. Parental blood samples screening using deletion junction-specific PCR revealed four parents with somatic mosaicism. Droplet digital PCR (ddPCR), qPCR, and amplicon-based next-generation sequencing (NGS) were applied to validate these findings. Using ddPCR levels of mosaicism ranged from undetectable to 18.5%. Amplicon-based NGS and qPCR for the father with undetectable mosaicism was able to detect mosaicism at 0.39%. In one mother, ddPCR analysis revealed 15.6%, 10.6%, 8.2%, and undetectable levels of mosaicism in her blood, buccal cells, saliva, and urine samples, respectively. Our data suggest that more sensitive and precise methods, e.g. CNV junction-specific LR-PCR, ddPCR, or qPCR may allow for a more refined assessment of the potential disease recurrence risk for an identified variant.
为了进一步评估父母体细胞镶嵌的规模和程度，我们在贝勒遗传学的 CMA 数据库中进行了查询。我们选择了 50 个无关的家庭，这些家庭中的受影响的先证者中发现了临床相关的明显从头 CNV-缺失。使用缺失连接特异性 PCR 对父母的血液样本进行筛查，发现了 4 名具有体细胞镶嵌的父母。采用液滴数字 PCR（ddPCR）、qPCR 和基于扩增子的下一代测序（NGS）来验证这些发现。使用 ddPCR 检测到的镶嵌率从无法检测到 18.5%不等。对未检测到镶嵌的父亲进行基于扩增子的 NGS 和 qPCR 检测，能够检测到 0.39%的镶嵌。在一位母亲中，ddPCR 分析分别显示她的血液、口腔细胞、唾液和尿液样本中的镶嵌率为 15.6%、10.6%、8.2%和无法检测到。我们的数据表明，更敏感和精确的方法，例如 CNV 连接特异性 LR-PCR、ddPCR 或 qPCR，可能允许更精细地评估已识别变体的潜在疾病复发风险。
