Burden analyses were performed on the matched set of 872 probands and siblings. Typically, three outcomes were assessed: proportion of individuals with ≥1 CNV matching the criteria (p-value calculated with Fisher's exact test); number of CNVs matching the criteria (p-value calculated with sign test); number of RefSeq genes within or overlapping CNVs matching the criteria (p-value calculated with Wilcoxon paired test). Where burden was assessed for unequal numbers of probands and siblings (e.g. by sex) the sign test and Wilcoxon paired test were replaced with the Wilcoxon test.
