Complex genomic rearrangements. Shown are examples of complex duplication-triplication-duplication rearrangements at MECP2  and LIS1 . (a, b) Array CGH using Agilent custom-designed arrays with interrogating oligonucleotides every few hundred base-pairs from the regions of the genome containing (a) MECP2 and (b) LIS1. Red dots indicate gain of copy number in relation to sex-matched reference DNA; black dots, copy number neutral; green dots, loss of copy number. (c, d) fluorescent in situ hybridization confirmation of the triplication of (c) MECP2 and (d) LIS1 (red, probe interrogating the indicated gene; green, control probe from same chromosome). Note that MECP2 (c) is on the one X chromosome in this male patient, whereas LIS1 (d) is on an autosome and shows both the duplicated (two red signals paired with one green control) with the normal chromosome 17 homologue, with only one copy of LIS1 paired with the green control signal.