of the 95% prediction ellipse and below the mean LRR for anomalies used to define the ellipse. The non-family studies were analyzed in a similar way, except that we replaced the class of transmitted anomalies with polymorphic CNVs. The latter were defined by hierarchical clustering to identify sets of anomalies with similar breakpoints. We then defined polymorphic sets as those with at least 4 members (but excluding sets with mean anomaly length greater than 10 Mb). We also included in the mosaic class three whole-autosome anomalies (12, 8, 22) that fell within the 3N ellipse, because constitutional trisomies for these chromosomes are not compatible with normal development1. Although we did not have access to biospecimens necessary for experimental validation of mosaics (i.e. live cells or those preserved for cytology), all anomalies classified as mosaics were manually reviewed and the BAF/LRR patterns that we observed are very similar to those reported by Peiffer17, Rodriguez-Santiago53 and Conlin7, who performed cytological validation for a variety of mosaic types.
