Genomic architecture of MDS. (A) Frequency of driver mutations identified in the sequencing screen or by cytogenetics in the cohort of 738 patients, broken down by MDS subtype. (B) Example of a copy number plot from a patient with a cytogenetically proven deletion on chromosome 5q. The upper panel depicts the normalized sequencing yields per exon; the lower panel depicts the variant allele fraction for germline SNPs. “AB” indicates the expected B-allele fractions for heterozygous SNPs; “AA” and “BB” indicate the position of the expected B-allele fractions for the homozygous SNPs AA and BB. (C) Associations among genes and cytogenetic abnormalities with disease subtypes in the study. Only associations with a q value (P value corrected for multiple hypothesis testing) <.1 are shown. Associations are colored by odds ratio. Blue-green colors depict gene-subtype associations that are observed together more than expected by chance, with brown colors depicting gene-subtype associations observed together less frequently than expected by chance.