This report deals with autosomal anomalies, defined here as deviations from the normal biparental disomic state. Anomalies were detected using log R ratio (LRR) and B Allele Frequency (BAF)17. LRR is a measure of relative signal intensity (log2 of the ratio of observed to expected intensity, where the expectation is based on other samples). BAF is an estimate of the frequency of the B allele of a given SNP in the population of cells from which the DNA was extracted. In a normal cell, the B allele frequency at any locus is either 0 (AA), ½ (AB) or 1 (BB) and the expected LRR is 0. Both copy number changes and copy-neutral changes from biparental to uniparental disomy (UPD) result in changes in BAF, while copy number changes also affect LRR (Figures 1 and 2). Our detection method identifies both non-mosaic (constitutional) and clonal mosaic anomalies, which were distinguished subsequently using standards based on parent-offspring transmission in family studies and polymorphic CNVs in non-family studies. Three types of clonal mosaics were detected: mixtures of disomic and monosomic cells (deletions), mixtures
