Fig. 1

Cytogenetics and molecular results. a. Cut-out of normal chromosome 1 and 22, aligned with their homologue translocation derivatives der(1) and der(22) in Q-banding at high resolution (≥550 bands). b. Results of metaphase FISH with custom SHANK3 probe (SureFISH Agilent) showing the normal chromosome 22 (arrow) and both der(1) and der(22) (arrowheads): red signals demonstrate the translocation’s reciprocity. c. Split-screen view of the reciprocal translocation (1,22) using the Integrative genomics viewer (IGV). The breakpoint regions for chromosome 22 (top) and for chromosome 1 (bottom) are shown. Curved lines with arrows link purple reads on chromosome 22 with their corresponding grey mates mapping on chromosome 1. Black boxes indicate the two subtle deletion regions on chromosome 22 and chromosome 1, respectively. PCR primers used to amplify the breakpoint regions on derivative 1 (der1F - der1R) and on derivative 22 (der22F – der22R) are also shown. d. Sanger sequencing defining the breakpoints at the base pair level on derivate 1 (top) and on derivative 22 (bottom). e. Karyogram and Sequence alignment of breakpoint junctions confirmed by Sanger sequencing. (left) High-resolution Q-banding ideograms of derivative der(1) (green with a small pink portion) and der(22) (pink with a green portion); (right) the junction of der1 (upper) showed a 2 bp (GA) microhomology and the der22 (bottom) junction showed a perfect fusion . Both chromosomes lost bases in the formation of the derivatives 1 and 22, 3.6 Kb on chromosome 22 and 4.1 Kb on chromosome 1