Fig. 2

Correlation between the inheritance of variants and incidence of second-site variants. A positive correlation was observed between the proportion of children with developmental delay with inherited primary CNVs (genomic disorders) and children with additional CNVs (Pearson’s product-moment correlation, ρ = 0.67 at significance level of p = 0.0001, for disorders affecting ≥ 6 children). Primarily de novo genomic disorders (e.g., Williams-Beuren syndrome) rarely show additional large CNVs, while CNVs (e.g., 16p12.1 deletion) that are primarily inherited have an excess of secondary CNVs compared to population controls (see Girirajan et al. [48] for more detail). AS Angelman syndrome, CNV copy number variant, PWS Prader-Willi syndrome, WBS Williams-Beuren syndrome. Adapted with permission from [48]