Fig. 1

a MFISH karyotype from the proband. The arrows point to the chromosome 7–11 translocation. b hypothetical steps involved in the proband’s rearrangement. Each of the putative breakpoints is identified by Greek letters. Breakpoints in 7p (α/α’) and 7q (β/β’) lead to a pericentric inversion of chromosome 7 to generate an inv7 intermediate. This was followed by a translocation between the inv7 p (γ/γ’) and 11 p (δ/δ’). c FISH with BACs (green signals) spanning the FOXP2 locus, on metaphase spreads from the proband. Each panel shows the hybridization signal from a single BAC probe, as indicated. The chromosomes are counterstained in DAPI, blue. The five BACs map to the normal chromosome 7 (white arrow), and to the derivative chromosome 11 (red arrow). No signal is found on the derivative chromosome 7 (green arrow). d Chromatogram of PCR mapping of the inversion breakpoint, with reference genome (GRCh37/hg19) sequences shown atop and breakpoint marked with a black arrow and dotted line. The sequence preceding the highlighted nucleotide “G” is on 7p21.1 (light green); the sequence following is on 7q31.1 (dark green). Segments in red show the respective continuing and preceding sequences on 7p21.1 and 7q31.1 in the reference genome