bioRxiv · 10.64898/2026.03.03.709017
Distinct mechanisms of CNV formation at the human 15q13.3 locus
Abstract
Human chromosome 15q13.3 is a hotspot for recurrent pathogenic copy number variants (CNVs), which remain unresolved at the sequence level. We generated haplotype-resolved assemblies for 10 patient-parent trios and found that both the long ("BP4-BP5") and short ("CHRNA7") forms of 15q13.3 CNVs arise predominantly by non-allelic homologous recombination (NAHR) enabled by inversion polymorphisms. While most BP4-BP5 CNVs are structurally distinct, three breakpoints cluster in a 2 kbp PRDM9-enriched recombination hotspot. CHRNA7 CNVs originate from NAHR between CHRNA7-LCR repeats embedded within locus-spanning inversions and give rise to paired deletion/duplication events. Population analyses of 581 population haplotypes reveal at least 18 distinct structural haplotypes in 15q13.3 and more than 10-fold ancestry-stratification of BP4-BP5 CNV risk, where 68.4% of Europeans but only 5.1% of East Asians are predisposed. Comparison to six ape species indicates that the duplication architecture promoting instability expanded recently and is largely human-specific.
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Höps, W., Porubsky, D., Yoo, D., de Groot, M., den Ouden, A., Derks, R., Hoekzema, K., Hoischen, A., Yntema, H. G., Human Pangenome Reference Consortium (HPRC),, Caro, P., De Falco, A., van Bon, B., Brunetti-Pierri, N., Schaaf, C. P., Eichler, E., Gilissen, C.. 2026-03-05. Distinct mechanisms of CNV formation at the human 15q13.3 locus. https://doi.org/10.64898/2026.03.03.709017
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