Description of CUX1 mutations in MNs. (A) Mapping of SNP-A karyotyping showing (n = 83) cases of deleted CUX1 gene (red: 49 monosomy 7, 28 deleted 7q, 6 microdeletions; blue: 4 cases compound heterozygous [monosomy 7 and CUX1 mutation]; green: 3 UPD 7q). CUX1 region indicated with horizontal rectangle. Pie chart shows the proportion of missense and truncating CUX1 mutations. CUX1 map showing mutation positions and absence of mutational hotspots. (B) Expression of CUX1 in MDS (n = 183) subtypes. A discrete subset of MDS cases with del7/7q (n = 7) exhibits low CUX1 expression defined as mean minus SD of healthy controls (n = 17; P = .004) and compared with MDSs with normal karyotyping (n = 94; P = .0001). A bar graph shows percentage of cases with CUX1 low expression in healthy controls, MDSs with normal karyotyping, and MDSs with del7/7q. CUX1 was most commonly underexpressed in MDSs with del7/7q. The paired Student t test was used to compare means across samples. P < .05 was considered statistically significant. NK, normal karyotyping.