Richard Rosenquist

The utility of whole-genome sequencing (WGS) for detecting childhood leukemia predisposition remains unclear. We perform a nationwide, prospective, population-based study of 181 children with acute leukemia to assess diagnostic yield and clinical utility of a uniformly applied three-pronged strategy, including systematic phenotyping, germline WGS-based 189-gene panel and tumor sequencing of positive cases. Trio-WGS is performed in 11 high-suspicion families. Nine patients have pathogenic germline alterations: six (3.3%) with leukemia predisposition syndromes ( TP53, CEBPA, DNMT3A , trisomy 21) and three (1.6%) with solid tumor predisposition syndromes ( MSH6, PALB2, SDHA ). Trio-WGS identifies one likely-pathogenic de novo DNMT3A variant. Six of nine diagnoses are previously unrecognized. Findings lead to tailored surveillance in 8/9 patients and treatment modifications in 4/9. Here, we show that this strategy gives a modest diagnostic yield. Nevertheless, the actionability of the findings supports its feasibility and validity in practice. Whether to restrict analysis to leukemia-relevant genes or broaden the panel should reflect local resources and counseling capacity.

High‐throughput sequencing has transformed clinical diagnostics of rare diseases (RD), cancer and infectious diseases by enabling the identification of disease‐causing genetic alterations and facilitating individualised treatment and care. In response to these advances, Genomic Medicine Sweden (GMS) was established in 2017 as a national collaborative effort to accelerate implementation of genomics‐based precision medicine within Sweden's regionally organized, publicly funded healthcare system. GMS brings together the seven university healthcare regions and their associated medical faculties, in collaboration with healthcare regions across Sweden, Science for Life Laboratory, patient organizations, industry and governmental agencies. Activities are coordinated through national disease‐specific expert groups, supported by cross‐cutting functions in bioinformatics, health economics, ethics, education and patient engagement. At the operational level, seven Genomic Medicine Centres, embedded at university hospitals, develop and deliver harmonised genomic diagnostics nationwide. The National Genomics Platform provides secure infrastructure for large‐scale data storage, analysis, and national and international data sharing. Following initial project‐based funding, GMS now receives long‐term governmental support. This review describes the national implementation of genomic‐based precision diagnostics, discusses challenges and lessons learnt, and highlights key milestones across disease areas, including whole‐genome sequencing in RD and paediatric cancer, comprehensive genomic profiling of haematological malignancies and solid tumours, pathogen genomics in microbiology, pharmacogenomic testing and emerging applications of polygenic risk scores in complex diseases. Collectively, these efforts have contributed to more than 500,000 genomic tests being performed within Swedish healthcare between 2017 and 2025. Finally, we outline future diagnostic needs and priority areas to ensure sustainable, scalable and equitable access to precision medicine.

Molecular tumor boards are supported by clinical decision support system (CDSS) tools for the interpretation of complex molecular data towards personalized treatments. Current CDSS tools are genomics-focused and characterized by tight couplings between data ingestion, guideline-based reasoning logic and curated knowledgebases. Next-generation CDSS solutions should integrate multimodal data and learn from outcomes in an interoperable ecosystem, leveraging explainable, trustworthy output from AI models through rigorous clinical validation processes.

Splenic marginal zone lymphoma (SMZL) is a rare B-cell malignancy with notable genetic, epigenetic, and clinical heterogeneity. This study utilized coding and non-coding sequencing (n=74), including whole-genome sequencing (WGS) on 24 paired tumour-normal samples, targeted sequencing (n=55) and DNA methylation in 126 cases to characterize the disease. From WGS, we identified recurrent, predominantly clonal, coding mutations in KLF2 (50%), KMT2D (25%) and NOTCH2 (25%), alongside rare mutations in FLNC (8%), novel mutations in FAM135B (17%) and non-coding mutational hotspots in BCL6, PAX5 and BACH2, linked to aberrant somatic hypermutation. At least one non-coding hotspot was detected in 69% of cases. Copy-number aberrations (CNAs) were present in 73% of cases, including del(7q) (27%), gain(3q) (17%) and trisomy 12 (13%). DNA methylation profiling revealed two epigenetic subgroups: SMZL-HR (high-risk, n=67) and SMZL-LR (low-risk, n=59). SMZL-HR was associated with adverse features such as female sex, IGHV1-2*04 usage, KLF2 mutations, del(7q), shorter telomeres, and elevated epiCMIT scores. Transcriptomic analysis highlighted enhanced cell proliferation in SMZL-HR, with enrichment of E2F and G2M checkpoint pathways and epigenetic regulation via EZH2. SMZL-HR patients had significantly shorter time to first treatment (TTFT) (HR: 1.9, p=.003) and reduced overall survival (HR: 2.5, p=.039): 85% of SMZL-HR patients required treatment and showed a higher frequency of transformation (p=.007) and mortality (p<.001). Multivariate analysis confirmed SMZL-HR as an independent predictor of shorter TTFT (HR: 2.4, p=.001). These findings demonstrate the role of DNA methylation and molecular profiling in SMZL risk stratification.