Publications by authors named "Gian A Thun"

Due to substantial improvements in read accuracy, third-generation long-read sequencing holds great potential in blood group diagnostics, particularly in cases where traditional genotyping or sequencing techniques, primarily targeting exons, fail to explain serological phenotypes. In this study, we employed Oxford Nanopore sequencing to resolve all genotype-phenotype discrepancies in the Kidd blood group system (JK, encoded by ) observed over seven years of routine high-throughput donor genotyping using a mass spectrometry-based platform at the Blood Transfusion Service, Zurich. Discrepant results from standard serological typing and donor genotyping were confirmed using commercial PCR-SSP kits.

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Background And Objectives: Mixed-field agglutination in ABO phenotyping (A, B) has been linked to genetically different blood cell populations such as in chimerism, or to rare variants in either ABO exon 7 or regulatory regions. Clarification of such cases is challenging and would greatly benefit from sequencing technologies that allow resolving full-gene haplotypes at high resolution.

Materials And Methods: We used long-read sequencing by Oxford Nanopore Technologies to sequence the entire ABO gene, amplified in two overlapping long-range PCR fragments, in a blood donor presented with AB phenotype.

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Article Synopsis
  • Acute porphyrias are inherited disorders that disrupt heme production, leading to severe neurovisceral symptoms under certain triggers.
  • A Swiss patient diagnosed with acute intermittent porphyria exhibited typical metabolic patterns, but routine genetic tests did not reveal any mutations in the expected gene.
  • Advanced sequencing techniques uncovered a de novo mosaic mutation in the patient, suggesting that such mutations may play a role in acute porphyrias when standard tests fail to identify a cause.
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Mucins are the main macrocomponents of the mucus layer that protects the digestive tract from pathogens. Fucosylation of mucins increases mucus viscoelasticity and its resistance to shear stress. These properties are altered in patients with ulcerative colitis (UC), which is marked by a chronic inflammation of the distal part of the colon.

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In the era of blood group genomics, reference collections of complete and fully resolved blood group gene alleles have gained high importance. For most blood groups, however, such collections are currently lacking, as resolving full-length gene sequences as haplotypes (ie, separated maternal/paternal origin) remains exceedingly difficult with both Sanger and short-read next-generation sequencing. Using the latest third-generation long-read sequencing, we generated a collection of fully resolved sequences for all 6 main ABO allele groups: ABO∗A1/A2/B/O.

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The sheer size of the human genome makes it improbable that identical somatic mutations at the exact same position are observed in multiple tumours solely by chance. The scarcity of cancer driver mutations also precludes positive selection as the sole explanation. Therefore, recurrent mutations may be highly informative of characteristics of mutational processes.

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Article Synopsis
  • - The study investigates whether high blood eosinophil counts have the same clinical significance in COPD (Chronic Obstructive Pulmonary Disease) as they do in asthma, revealing ongoing debates in the medical community.
  • - Researchers analyzed data from two cohorts (COPD and asthma) to study gene expression and the relationship between eosinophil counts and clinical characteristics, finding distinct genetic responses between the two conditions.
  • - The findings indicate that while asthma and COPD may share some clinical features, their underlying molecular mechanisms differ significantly, emphasizing the complexity of treating these respiratory diseases.
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Background And Aims: Alpha-1 antitrypsin (A1AT) is the most abundant serine protease inhibitor in human blood and exerts important anti-inflammatory and immune-modulatory effects. In combination with smoking or other long-term noxious exposures such as occupational dust and fumes, genetic A1AT deficiency can cause chronic obstructive pulmonary disease, a condition with elevated cardiovascular risk. The effects of A1AT deficiency on cardiovascular risk have hardly been studied today.

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Background: Both air pollution and genetic variation have been shown to affect lung function. Their interaction has not been studied on a genome-wide scale to date.

Objectives: We aimed to identify, in an agnostic fashion, genes that modify the association between long-term air pollution exposure and annual lung function decline in an adult population-based sample.

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Article Synopsis
  • Improved air quality was linked to a slower decline in lung function, but the influence of specific genetic factors (single nucleotide polymorphisms) on this relationship had not been previously researched.
  • The study analyzed data from 4,310 participants over 11 years, examining the effects of genetic variants and exposure to particulate matter on lung function decline.
  • While one genetic variant (rs2284746) showed a moderate interaction with improved air quality, the overall evidence indicated that genetic polymorphisms did not strongly affect the benefits of better air quality on lung function decline.
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Several infrequent genetic polymorphisms in the SERPINA1 gene are known to substantially reduce concentration of alpha1-antitrypsin (AAT) in the blood. Since low AAT serum levels fail to protect pulmonary tissue from enzymatic degradation, these polymorphisms also increase the risk for early onset chronic obstructive pulmonary disease (COPD). The role of more common SERPINA1 single nucleotide polymorphisms (SNPs) in respiratory health remains poorly understood.

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Objective: The molecular mechanisms underlying the association between obesity (BMI ≥ 30 kg/m(2)) and asthma are poorly understood. Since shifts in the fate of bronchial cells due to low-grade systemic inflammation may provide a possible explanation, we investigated whether two of the best documented functional variants in cell cycle control genes modify the obesity-asthma association.

Methods: We genotyped 5930 SAPALDIA cohort participants for the single-nucleotide polymorphisms (SNPs) rs9344 in the cyclin D1 gene (CCND1) and rs1042522 in the gene encoding tumor protein 53 (TP53).

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Elevated serum urate concentrations can cause gout, a prevalent and painful inflammatory arthritis. By combining data from >140,000 individuals of European ancestry within the Global Urate Genetics Consortium (GUGC), we identified and replicated 28 genome-wide significant loci in association with serum urate concentrations (18 new regions in or near TRIM46, INHBB, SFMBT1, TMEM171, VEGFA, BAZ1B, PRKAG2, STC1, HNF4G, A1CF, ATXN2, UBE2Q2, IGF1R, NFAT5, MAF, HLF, ACVR1B-ACVRL1 and B3GNT4). Associations for many of the loci were of similar magnitude in individuals of non-European ancestry.

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Rationale: α1-Antitrypsin (AAT) deficiency is one of the commonest rare respiratory disorders worldwide. Diagnosis, assessment of risk for developing chronic obstructive pulmonary disease (COPD), and management of replacement therapy require the availability of precise and updated ranges for protein serum levels.

Objective: This paper aims to provide ranges of serum AAT according to the main genotype classes in the general population.

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Article Synopsis
  • Genome-wide association studies previously focused on chronic lung diseases but not on lung function decline.
  • The study analyzed genetic factors affecting the age-related decrease in FEV(1) and FEV(1)/FVC ratios among asthmatic and nonasthmatic adults of European descent.
  • Key findings indicate differences in genetic associations between the two groups, with some SNPs replicating across cohorts and suggesting that genetic influences on lung function decline may differ from those affecting lung function at a single point in time.
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