Biallelic disruption of DDX41 activity is associated with distinct genomic and immunophenotypic hallmarks in acute leukemia

Clinicopathological and prognostic significance of DDX41 mutation in myeloid neoplasms: a systematic review and meta-analysis

DDX41 is one of the most frequently altered genes in familial acute myeloid leukemia/myelodysplastic syndrome (AML/MDS). Mutation of DDX41 has been widely reported in various types of myeloid neoplasms. This systematic review and meta-analysis were conducted to assess the clinical characteristics and relationship between DDX41 mutations and OS in myeloid neoplasm patients. We thoroughly searched the PubMed, the Cochrane Library, Embase, Web of Science, MEDLINE, and Google Scholar databases. Two reviewers separately reviewed and extracted the data. Twenty studies totaling 9,058 patients have been integrated into the meta-analysis. The extensive pooled analysis showed a significant association between DDX41 mutations and improved OS (HR 0.70, 95% CI 0.52-0.93, P = 0.01). Subgroup analysis confirmed that DDX41 mutation operated to be a reliable positive indicator of OS when subdivided by different types of myeloid neoplasms. In terms of the clinicopathological value, DDX41 mutations were significantly correlated with the male sex. Age, AML prevalence, bone marrow, or white blood cell counts did not correlate with any findings. The top three genetic variants were p.M1I, p.D140fs, and p.R525H. Co-mutations in patients with DDX41 mutations most commonly include the following: additional sex combs-like 1 (ASXL1), DNA methyltransferase 3 A (DNMT3A), tumor protein p53 (TP53), ten-eleven translocation 2 (TET2) and serine/arginine-rich splicing factor 2 (SRSF2). Our results substantiate that DDX41 mutations were associated with significantly good OS and provide more insight into the clinicopathological characteristics of DDX41 mutations in individuals with myeloid neoplasms.

Germline DDX41 mutations in myeloid neoplasms: the current clinical and molecular understanding

PURPOSE OF REVIEW

DDX41 mutations are the most common cause of germline predisposition to adult-onset myeloid neoplasms. The unique mutational landscape and clinical features indicate a distinct molecular pathogenesis, but the precise mechanism by which DDX41 mutations cause disease is poorly understood, owing to the multitude of DDX41 functions. In this review, we will update DDX41's known functions, present unique clinical features and treatment considerations, and summarize the current understanding of the molecular pathogenesis of the disease.

RECENT FINDINGS

Large cohort studies have revealed that germline DDX41 variants are heterozygous and predominantly loss-of-function. Acquired mutation of the contralateral DDX41 allele, typically R525H, is present in more than half of patients at disease onset, which occurs after age 50. DDX41 is essential for hematopoiesis and has versatile functions in RNA metabolism and innate immune sensing. Experimental models have suggested that innate immune activation downstream of defects in R-loop resolution and ribosome biogenesis plays a key role in the pathogenesis.

SUMMARY

While intensive investigations unveiled a strong genotype-phenotype relationship, the optimal therapeutic approach and long-term outcome are undefined. There is an urgent need to scrutinize the patients at single cell and multiomics level and to advance experimental animal and human models to fully elucidate the molecular pathogenesis.

DDX41: exploring the roles of a versatile helicase

DDX41 is a DEAD-box helicase and is conserved across species. Mutations in DDX41 have been associated with myeloid neoplasms, including myelodysplastic syndrome and acute myeloid leukemia. Though its pathogenesis is not completely known, DDX41 has been shown to have many cellular roles, including in pre-mRNA splicing, innate immune sensing, ribosome biogenesis, translational regulation, and R-loop metabolism. In this review, we will summarize the latest understandings regarding the various roles of DDX41, as well as highlight challenges associated with drug development to target DDX41. Overall, understanding the molecular and cellular mechanisms of DDX41 could help develop novel therapeutic options for DDX41 mutation-related hematologic malignancies.

Germline Variants and Characteristic Features of Hereditary Hematological Malignancy Syndrome

Due to the proliferation of genetic testing, pathogenic germline variants predisposing to hereditary hematological malignancy syndrome (HHMS) have been identified in an increasing number of genes. Consequently, the field of HHMS is gaining recognition among clinicians and scientists worldwide. Patients with germline genetic abnormalities often have poor outcomes and are candidates for allogeneic hematopoietic stem cell transplantation (HSCT). However, HSCT using blood from a related donor should be carefully considered because of the risk that the patient may inherit a pathogenic variant. At present, we now face the challenge of incorporating these advances into clinical practice for patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) and optimizing the management and surveillance of patients and asymptomatic carriers, with the limitation that evidence-based guidelines are often inadequate. The 2016 revision of the WHO classification added a new section on myeloid malignant neoplasms, including MDS and AML with germline predisposition. The main syndromes can be classified into three groups. Those without pre-existing disease or organ dysfunction; DDX41, TP53, CEBPA, those with pre-existing platelet disorders; ANKRD26, ETV6, RUNX1, and those with other organ dysfunctions; SAMD9/SAMD9L, GATA2, and inherited bone marrow failure syndromes. In this review, we will outline the role of the genes involved in HHMS in order to clarify our understanding of HHMS.