Due to the increased accuracy of Copy Number Variable region (CNV) break point mapping, it is now possible to say with a reasonable degree of confidence whether a gene (i) falls entirely within a CNV; (ii) overlaps the CNV or (iii) actually contains the CNV. We classify these as type I, II and III CNV genes respectively.
Woodwark, C., & Bateman, A. (2011). The characterisation of three types of genes that overlie copy number variable regions. PLoS ONE, 6(5). https://doi.org/10.1371/journal.pone.0014814