Prevalence and significance of DDX41 gene variants in the general population.

Germline variants in the DDX41 gene have been linked to myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) development. However, the risks associated with different variants remain unknown, as do the basis of their leukemogenic properties, impact on steady-state hematopoiesis and links to other cancers. Here, we investigate the frequency and significance of DDX41 variants in 454,792 United Kingdom Biobank (UKB) participants and identify 452 unique non-synonymous DNA variants in 3,538 (1/129) individuals. Many were novel and prevalence of most varied markedly by ancestry. Amongst the 1059 individuals with germline pathogenic variants (DDX41-GPV) 34 developed MDS/AML (odds ratio 12.3 versus non-carriers). Of these 7/218 had start-loss, 22/584 truncating and 5/257 missense (odds ratios: 12.9, 15.1 and 7.5 respectively). Using multivariate regression, we found significant associations of DDX41-GPV with MDS, AML and "family history of leukemia", but not lymphoma, myeloproliferative neoplasms or other cancers. We also report that DDX41-GPV carriers do not have an increased prevalence of clonal hematopoiesis (CH). In fact, CH was significantly more common prior to sporadic versus DDX41-mutant MDS/AML, revealing distinct evolutionary paths. Furthermore, somatic mutation rates did not differ between sporadic and DDX41-mutant AML genomes, ruling out genomic instability as a driver of the latter. Finally, we found that higher mean red cell volume and somatic DDX41 mutations in blood DNA identify DDX41-GPV carriers at increased MDS/AML risk. Collectively, our findings give new insights into the prevalence and cognate risks associated with DDX41 variants, as well as the clonal evolution and early detection of DDX41-mutant MDS/AML.