Quantitative Assessment of Parental Somatic Mosaicism for Copy-Number Variant (CNV) Deletions.

Quantitative Assessment of Parental Somatic Mosaicism for Copy-Number Variant (CNV) Deletions. Curr Protoc Hum Genet. 2020 Jun;106(1):e99 Authors: Liu Q, Grochowski CM, Bi W, Lupski JR, Stankiewicz P Abstract As genome sequencing methodologies have become more sensitive in detecting low-frequency rare-variant events, the link between post-zygotic mutagenesis and somatic mosaicism in the etiology of several human genetic conditions other than cancers has become more clear. Given that current clinical-genomics diagnostic methods have limited detection sensitivity for mosaic events, a copy-number variant (CNV) deletion inherited from a parent with low-level (<10%) mosaicism can be erroneously interpreted in the proband to represent a de novo germline event. Here, we describe three sensitive, precise, and cost-efficient methods that can quantitatively assess the potential degree of parental somatic mosaicism levels for CNV deletions: droplet digital PCR (ddPCR), PCR amplicon-based next-generation sequencing (NGS), and quantitative PCR. ddPCR using the EvaGreen fluorescent dye protocol can specifically quantify the deleted or non-deleted alleles by analyzing the number of droplets positive for a fluorescent signal for each event. PCR amplicon-based NGS assesses the allele frequencies of a heterozygous single-nucleotide polymorphism within a deletion region. The difference in number of reads between the two genotypes indicates the level...
Source: Current Protocols in Human Genetics - Category: Genetics & Stem Cells Tags: Curr Protoc Hum Genet Source Type: research