DECIPHER CNVs whose pathomechanism can be explained by TDBD. (A) Candidate TDBD at the FOXG1 locus. Three of the 40 candidate TDBD cases identified in this study are located adjacent to the FOXG1 gene. They are truncating mutations associated with neurodevelopmental phenotypes such as Rett syndrome . All these microdeletions overlap the gene PRKD1 and a topological boundary region but not FOXG1 itself. Human element hs433 is shown as an image from the VISTA enhancer browser . (B) A deletion of about 3.9 Mb on chromosome 10 leads to haploinsufficiency of a number of genes with no known phenotypic relevance to the CNV phenotype of multiple renal cysts (HP:0005562). The deletion also removes a total of five TDBs that lie between several predicted kidney-specific enhancer elements and the gene FGFR2. chr14, chromosome 14; CNV, copy-number variation/variant; kb, kilobase; Mb, megabase; TDB, topological domain boundary; TDBD, TDB disruption; UCSC: University of California, Santa Cruz Genome Browser.