TY - JOUR A1 - Vervoort, Lisanne A1 - Dierckxsens, Nicolas A1 - Sousa Santos, Marta A1 - Meynants, Senne A1 - Souche, Erika A1 - Cools, Ruben A1 - Heung, Tracy A1 - Devriendt, Koen A1 - Peeters, Hilde A1 - McDonald-McGinn, Donna M. A1 - Swillen, Ann A1 - Breckpot, Jeroen A1 - Emanuel, Beverly S. A1 - Van Esch, Hilde A1 - Bassett, Anne S. A1 - Vermeesch, Joris R. T1 - Multiple paralogs and recombination mechanisms contribute to the high incidence of 22q11.2 deletion syndrome Y1 - 2025/04/01 JF - Genome Research JO - Genome Research SP - 786 EP - 797 DO - 10.1101/gr.279331.124 VL - 35 IS - 4 UR - http://genome.cshlp.org/content/35/4/786.abstract N2 - The 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion disorder. Why the incidence of 22q11.2DS is much greater than that of other genomic disorders remains unknown. Short-read sequencing cannot resolve the complex segmental duplications (SDs) to provide direct confirmation of the hypothesis that the rearrangements are caused by nonallelic homologous recombination between the low copy repeats on Chromosome 22 (LCR22s). To enable haplotype-specific assembly and rearrangement mapping in LCR22 clusters, we combined fiber-FISH optical mapping with whole-genome (ultra-)long-read sequencing or rearrangement-specific long-range PCR on 25 families comprising several different LCR22-mediated rearrangements. We demonstrate that not only different paralogous SDs but also palindromic AT-rich repeats (PATRR) within LCR22s are driving 22q11.2 rearrangements. In addition, we show the existence of two different inversion polymorphisms preceding rearrangement, and somatic mosaicism. The existence of different recombination sites and mechanisms in paralogs and PATRRs, which are copy number expanding in the human population, is a likely contributor for the high 22q11.2DS incidence. ER -