Exploring the Functional Impact of Individual DDX41 Variants With a Fast and Robust Cell-Based Method

Area of Science:

• Hematology
• Genetics
• Molecular Biology

Background:

• Germline DDX41 variants are implicated in acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS).
• These variants show a higher prevalence in males and are associated with late-onset disease.
• Assessing the functional impact of DDX41 variants, especially variants of uncertain significance (VUSs), is crucial for accurate diagnosis.

Purpose of the Study:

• To determine the frequency of germline DDX41 variants in Danish patients with suspected myeloid neoplasms.
• To functionally characterize DDX41 variants of uncertain significance (VUSs) using a cell-based assay.
• To evaluate the utility of CRISPR-Select in distinguishing pathogenic from benign DDX41 variants.

Main Methods:

• Analysis of germline DDX41 variants in 647 Danish patients.
• Generation of a monoallelic DDX41 K562 cell line.
• CRISPR-Select assay to assess the impact of variants on cell proliferation and survival.

Main Results:

• Identified 16 DDX41 variants in 30 patients, with 14 confirmed as germline.
• Eight germline variants were classified as likely pathogenic/pathogenic (LP/P), and three as VUSs.
• Pathogenic DDX41 variants impaired cell proliferation, while benign variants did not; one VUS was reclassified as pathogenic.

Conclusions:

• Confirmed a 2.4% frequency of LP/P DDX41 germline variants in Danish patients.
• Demonstrated that CRISPR-Select is valuable for assessing the pathogenicity of DDX41 variants.
• Highlighted the potential of functional assays to reclassify VUSs and improve patient management.