Publications by authors named "Thomas v O Hansen"

Background: Men with pathogenic BRCA1/2 variants are at higher risk of prostate cancer We included men with likely pathogenic/pathogenic (LP/P) variants in BRCA1/2 in a prostate-specific antigen (PSA) screening program after cascade germline testing since 2014. PSA was tested yearly and an age-specific low PSA threshold for biopsy was used, to determine if a low PSA threshold for biopsy is justified for men with pathogenic BRCA1/2 variants.

Methods: From 2014 to 2023 a total of 340 men were included in the program.

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An increasing number of autosomal recessive forms of adenomatous polyposis have been described, but some in very few cases. Here, we describe a rare case of biallelic germline pathogenic variants in the MLH3 gene, implicating it as a potential cause of early colorectal cancer. The patient, a 47-year-old woman, presented with rectal bleeding, leading to the discovery of a malignant rectal tumor and adenomas during colonoscopy.

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Background: Pathogenic variants in the mismatch repair genes are associated with an elevated lifetime risk of colorectal cancer (CRC). We previously identified two variants of uncertain significance (VUS) in the MLH1 gene, c.696_698del, p.

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Introduction: Familial adenomatous polyposis (FAP) is caused by pathogenic variants in the APC gene. FAP is usually categorized according to phenotype: classical FAP (CFAP) and attenuated FAP (AFAP); the latter is considered to have a milder disease course. We aimed to assess the risk of overall and specific cancers in patients with CFAP and AFAP compared with matched, nonexposed individuals.

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Article Synopsis
  • - Pathogenic variants in the APC gene are responsible for familial adenomatous polyposis, the most common hereditary gastrointestinal polyposis syndrome, prompting the development of specific classification criteria to aid in variant interpretation.
  • - The study involved applying these APC-specific criteria to assess over 10,000 unique APC variants from databases like ClinVar and LOVD, leading to a significant reclassification of variants of uncertain significance (VUSs), with many being reassessed as (likely) benign or (likely) pathogenic.
  • - The results showed that using these tailored criteria effectively reduced VUSs by 37%, highlighted the potential for systematic variant classification in large datasets, and established a model that could benefit future genetic variant interpretation efforts in
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Article Synopsis
  • The study focused on improving the classification of genetic variants linked to familial adenomatous polyposis using APC-specific criteria developed by an expert panel.
  • A total of 10,228 unique variants were analyzed, resulting in 41% of VUS from ClinVar and 61% from LOVD being reclassified, primarily as (Likely) Benign, which reduced the overall VUS by 37%.
  • The research highlighted a systematic approach to variant classification in large datasets that could be applied to other gene/disease interpretations and allowed for prioritization of VUS requiring further evidence collection.
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The care for patients with serious conditions is increasingly guided by genomic medicine, and genomic medicine may equally transform care for healthy individual if genomic population screening is implemented. This study examines the medical impact of opportunistic genomic screening (OGS) in a cohort of patients undergoing comprehensive genomic germline DNA testing for childhood cancer, including the impact on their relatives. Medical actionability and uptake after cascade testing in the period following disclosure of OGS results was quantified.

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Alu elements are short, interspersed elements located throughout the genome, playing a role in human diversity, and occasionally causing genetic diseases. Here, we report a novel Alu insertion causing Mowat-Wilson syndrome, a rare neurodevelopmental disorder, in an 8-year-old boy displaying the typical clinical features for Mowat-Wilson syndrome. The variant was not initially detected in genome sequencing data, but through deep phenotyping, which pointed to only one plausible candidate gene, manual inspection of genome sequencing alignment data enabled us to identify a de novo heterozygous Alu insertion in exon 8 of the ZEB2 gene.

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Background: Nineteen genomic regions have been associated with high-grade serous ovarian cancer (HGSOC). We used data from the Ovarian Cancer Association Consortium (OCAC), Consortium of Investigators of Modifiers of (CIMBA), UK Biobank (UKBB), and FinnGen to identify novel HGSOC susceptibility loci and develop polygenic scores (PGS).

Methods: We analyzed >22 million variants for 398,238 women.

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In the Danish Polyposis Register, patients with over 100 cumulative colorectal adenomas of unknown genetic etiology, named in this study colorectal polyposis (CP), is registered and treated as familial adenomatous polyposis (FAP). In this study, we performed genetic analyses, including whole genome sequencing (WGS), of all Danish patients registered with CP and estimated the detection rate of pathogenic variants (PV). We identified 231 families in the Polyposis Register, 31 of which had CP.

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Germline pathogenic variants associated with increased childhood mortality must be subject to natural selection. Here, we analyze publicly available germline genetic metadata from 4,574 children with cancer [11 studies; 1,083 whole exome sequences (WES), 1,950 whole genome sequences (WGS), and 1,541 gene panel] and 141,456 adults [125,748 WES and 15,708 WGS]. We find that pediatric cancer predisposition syndrome (pCPS) genes [n = 85] are highly constrained, harboring only a quarter of the loss-of-function variants that would be expected.

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Background: Reports of dual carriers of pathogenic BRCA1 variants in trans are extremely rare, and so far, most individuals have been associated with a Fanconi Anemia-like phenotype.

Methods: We identified two families with a BRCA1 in-frame exon 20 duplication (Ex20dup). In one male individual, the variant was in trans with the BRCA1 frameshift variant c.

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Variants which disrupt splicing are a frequent cause of rare disease that have been under-ascertained clinically. Accurate and efficient methods to predict a variant's impact on splicing are needed to interpret the growing number of variants of unknown significance (VUS) identified by exome and genome sequencing. Here, we present the results of the CAGI6 Splicing VUS challenge, which invited predictions of the splicing impact of 56 variants ascertained clinically and functionally validated to determine splicing impact.

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Pathogenic variants in several genes involved in the function or regulation of smooth muscle cells (SMC) are known to predispose to congenital heart disease and thoracic aortic aneurysm and dissection (TAAD). Variants in MYLK are primarily known to predispose to TAAD, but a growing body of evidence points toward MYLK also playing an essential role in the regulation of SMC contraction outside the aorta. In this case report, we present a patient with co-occurrence of persistent ductus arteriosus (PDA) and thoracic aortic dissection.

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Article Synopsis
  • The Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (VCEP) was created to improve the interpretation of APC gene variants associated with Familial Adenomatous Polyposis, a common hereditary condition.
  • Through analysis and expert input, the panel developed gene-specific modifications to existing variant classification guidelines, piloting these changes on 58 variants.
  • The new APC-specific criteria successfully reduced the number of uncertain significance variants and maintained the classification of well-established ones, which will aid future clinical applications.
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Purpose: Germline pathogenic variants in CHEK2 confer moderately elevated breast cancer risk (odds ratio, OR ∼ 2.5), qualifying carriers for enhanced breast cancer screening. Besides pathogenic variants, dozens of missense CHEK2 variants of uncertain significance (VUS) have been identified, hampering the clinical utility of germline genetic testing (GGT).

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Background: Exon deletions are generally considered pathogenic, particularly when they are located out of frame. Here, we describe a pediatric, female patient presenting with hypercalcemia and a small cell carcinoma of the ovary, hypercalcemic type, and carrying a germline de novo SMARCA4 exon 14 deletion.

Methods: The SMARCA4 deletion was identified by whole genome sequencing, and the effect on the RNA level was examined by gel- and capillary electrophoresis and nanopore sequencing.

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The three major collagen VI genes: COL6A1, COL6A2, and COL6A3 encode microfibrillar components of extracellular matrices in multiple tissues including muscles and tendons. Pathogenic variants in the collagen VI genes cause collagen VI-related dystrophies representing a continuum of conditions from Bethlem myopathy at the milder end to Ullrich congenital muscular dystrophy at the more severe end. Here we describe a pathogenic variant in the COL6A1 gene (NM_001848.

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Background: Studies suggest that Wilms tumours (WT) are caused by underlying genetic (5%-10%) and epigenetic (2%-29%) mechanisms, yet studies covering both aspects are sparse.

Methods: We performed prospective whole-genome sequencing of germline DNA in Danish children diagnosed with WT from 2016 to 2021, and linked genotypes to deep phenotypes.

Results: Of 24 patients (58% female), 3 (13%, all female) harboured pathogenic germline variants in WT risk genes ( and ).

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Background: Birt-Hogg-Dubé (BHD) syndrome is a rare genetic syndrome caused by pathogenic or likely pathogenic germline variants in the gene. Patients with BHD syndrome have an increased risk of fibrofolliculomas, pulmonary cysts, pneumothorax and renal cell carcinoma. There is debate regarding whether colonic polyps should be added to the criteria.

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The contribution of germline copy number variants (CNVs) to risk of developing cancer in individuals with pathogenic BRCA1 or BRCA2 variants remains relatively unknown. We conducted the largest genome-wide analysis of CNVs in 15,342 BRCA1 and 10,740 BRCA2 pathogenic variant carriers. We used these results to prioritise a candidate breast cancer risk-modifier gene for laboratory analysis and biological validation.

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Skipping of BRCA2 exon 3 (∆E3) is a naturally occurring splicing event, complicating clinical classification of variants that may alter ∆E3 expression. This study used multiple evidence types to assess pathogenicity of 85 variants in/near BRCA2 exon 3. Bioinformatically predicted spliceogenic variants underwent mRNA splicing analysis using minigenes and/or patient samples.

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The genetic background of familial, late-onset colorectal cancer (CRC) (i.e., onset > age 50 years) has not been studied as thoroughly as other subgroups of familial CRC, and the proportion of families with a germline genetic predisposition to CRC remains to be defined.

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