Spatial expression patterns of CNV genes distribution of CNV (black) and non-CNV (white) expressed transcripts in function of the number of anatomical structures in which they are detected at embryonic stage E14.5 by in situ hybridization performed by the EURexpress consortium (http://www.eurexpress.org/ee/). CNV genes are expressed in a significantly smaller number of anatomical structures (two-tailed Mann-Whitney U-test, P = 0.04).