Hypothesized mechanism of the mosaic unbalanced translocation. a Left: Balanced translocation between chromosome 3 (light blue) and chromosome 12 (orange) in Mother; Right: Meiotic recombination at chromosome 3p. b Cell line 1 contains two normal chromosome 3 (dark blue/light blue from Mom and purple from Dad), the derivative 12 (orange/light blue from Mom) and a normal chromosome 12 (red from Dad). Cell line 2 contains two normal chromosome 3, a paternal normal chromosome 12 (red) and a normal chromosome 12 resulted from mitotic rescue (orange/red). c Schematic explanation of the B-allele frequencies in SNP array. Left: Breakpoints are marked to delineate the mosaic duplication on 3p, the 5.7 Mb distal part with two haplotypes (light blue and purple) and the 2.6 Mb proximal part with three haplotypes (light blue, dark blue, and purple); Right: Breakpoints are marked to delineate the 6.1 Mb mosaic deletion on 12p with ROH (red only) and the adjacent 1.9 Mb mosaic copy number neutral ROH region (red and orange)