clinically relevant mosaicism likely underestimated

"mosaic variants considered likely or definitively contributory to phenotype were detected in approximately 1.5% of probands in whom a molecular diagnosis was ascertained. Parental mosaicism was identified in 0.3% of families analyzed. We observed that certain genes, pathways, and even individuals were prone to mosaic variation and that SNV mosaicism can be an indication of underlying structural variation. Since clinical ES by design favors breadth over depth of coverage and only blood samples were analyzed in this study, this analysis likely underestimates the true frequency of clinically relevant mosaicism in our cohort."

PMID: 31349857. A clinical survey of mosaic single nucleotide variants in disease-causing genes detected by exome sequencing https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6660700/