Mapping inversion and translocation breakpoints by MLPA. The relative dosage of 33 loci along 22q11 were assessed in genomic DNA samples derived from the proband (47,XX,+der(22) (q24.1;q11.2)pat) (red circles), her father (balanced t(8;22) carrier) (blue circles), and her unaffected mother (green circles) by MLPA. Dosage at each target locus is expressed as a dosage quotient relative to controls (data not shown). Dashed lines corresponding to established threshold values (Bunyan et al. 2004) are drawn such that dosage quotients between 0.3 and 0.7 are considered disomic (2N), below 0.7 haploid (1N), above 1.3 trisomic (3N). MLPA probes corresponding to 22q11 loci are listed on the X axis in relative order. The location and relative size of LCRs are indicated by gray shading. (CECR) Cat eye syndrome minimal chromosomal region.