1q21.1 copy number variation (deletion or duplication) syndromes are known for a highly variable phenotype especially concerning psychiatric problems. The genes on the red DNA strand represents the deleted, or duplicated, region. The downstream effects and interaction partners of the different genes are shown according to available knowledge. The breakpoints (chr1:146,527,987-147,394,444, GRCh37/hg19) are defined as given in Kendall et al. 2017: https://doi.org/10.1016/j.biopsych.2016.08.014.