Identification and prevention of genotyping errors caused by G-quadruplex- and i-motif-like sequences.

2009

Abstract Background: Reliable PCR amplification of DNA fragments is the prerequisite for most genetic assays. We investigated the impact of G-quadruplex– or i-motif–like sequences on the reliability of PCR-based genetic analyses. Methods: We found the sequence context of a common intronic polymorphism in the MEN1 gene (multiple endocrine neoplasia I) to be the cause of systematic genotyping errors by inducing preferential amplification of one allelic variant [allele dropout (ADO)]. Bioinformatic analyses and pyrosequencing-based allele quantification enabled the identification of the underlying DNA structures. Results: We showed that G-quadruplex– or i-motif–like sequences can reproducibly …

Gene variants of osteoprotegerin, estrogen-, calcitonin- and vitamin D-receptor genes and serum markers of bone metabolism in patients with Gaucher d…

2018

Anca Zimmermann,1 Radu A Popp,2 Heidi Rossmann,3 Simona Bucerzan,4 Ioana Nascu,4 Daniel Leucuta,5 Matthias M Weber,1 Paula Grigorescu-Sido41Department of Endocrinology and Metabolic Diseases, 1st Clinic and Polyclinic of Internal Medicine, University of Mainz, Mainz, Germany; 2Department of Medical Genetics, University of Medicine and Pharmacy, Cluj-Napoca, Romania; 3Institute for Clinical Chemistry and Laboratory Medicine, University of Mainz, Mainz, Germany; 4Center of Genetic Diseases, 1st Pediatric Clinic, University of Medicine and Pharmacy, Cluj-Napoca, Romania; 5Department of Medical Informatics and Biostatistics, University of Medicine and Pharmacy, Cluj-Napoca, RomaniaPurpose: Oste…

c.451dupT in KLKB1 is common in Nigerians, confirming a higher prevalence of severe prekallikrein deficiency in Africans compared to Europeans

2020

Essentials Prekallikrein (PK) deficiency is a recessive trait with isolated aPTT prolongation. KLKB1 c.451dupT is common in Nigerians (7/600 alleles) and absent in a European group (0/600). To date, all genotyped PK-deficient patients of African ancestry were homozygous for 451dupT. Diagnostics of isolated aPTT prolongation in African descendants should include PK testing. ABSTRACT: Background Severe prekallikrein deficiency (PK deficiency) is an autosomal-recessive condition thought to be very rare. Recently we reported that the previously unnoticed variant c.451dupT, p.Ser151Phefs*34 in KLKB1, which is listed in databases aggregating genome data, causes PK deficiency and is common in Afri…

Pathogenic lipid‐binding antiphospholipid antibodies are associated with severity of COVID‐19

2021

Abstract Background Coronavirus disease 19 (COVID‐19)–associated coagulopathy is a hallmark of disease severity and poor prognosis. The key manifestations of this prothrombotic syndrome—microvascular thrombosis, stroke, and venous and pulmonary clots—are also observed in severe and catastrophic antiphospholipid syndrome. Antiphospholipid antibodies (aPL) are detectable in COVID‐19 patients, but their association with the clinical course of COVID‐19 remains unproven. Objectives To analyze the presence and relevance of lipid‐binding aPL in hospitalized COVID‐19 patients. Methods Two cohorts of 53 and 121 patients from a single center hospitalized for PCR‐proven severe acute respiratory syndro…

Immunogenic hotspots in the spacer domain of ADAMTS13 in immune‐mediated thrombotic thrombocytopenic purpura

2021

International audience; Background Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is caused by anti-ADAMTS13 autoantibodies inducing a severe deficiency of ADAMTS13. Epitope mapping studies on samples obtained during acute iTTP episodes have shown that the iTTP immune response is polyclonal, with almost all patients having autoantibodies targeting the spacer domain of ADAMTS13.Objectives To identify the immunogenic hotspots in the spacer domain of ADAMTS13.Patients/methods A library of 11 full-length ADAMTS13 spacer hybrids was created in which amino acid regions of the spacer domain of ADAMTS13 were exchanged by the corresponding region of the spacer domain of ADAMTS1. Next, th…

Stage-dependent agreement between cerebrospinal fluid proteins and FDG-PET findings in Alzheimer's disease.

2011

Cerebral hypometabolism and abnormal levels of amyloid beta (Aβ), total (t-tau) and phosphorylated tau (ptau) proteins in cerebrospinal fluid (CSF) are established biomarkers of Alzheimer's disease (AD). We examined the agreement between these biomarkers in a single center study of patients with AD of severity extending over a wide range. Forty seven patients (MMSE 21.4 ± 3.6, range 13-28 points) with incipient and probable AD underwent positron emission tomography with [18F]-fluorodeoxyglucose (FDG-PET) and lumbar puncture for CSF assays of Aβ1-42, p-tau181, and t-tau. All findings were classified as either positive or negative for AD. Statistical analyses were performed for the whole samp…

Chronic Diarrhea in a 5-Year-Old Girl: Pitfall in Routine Laboratory Testing with Potentially Severe Consequences

2009

A 5-year-old girl was referred because of recurrent watery diarrhea, abdominal pain, and flatulence. She was the second of 3 children. Her 10-year-old sister was normally developed and healthy. Her younger brother has meningomyelocele and hydrocephalus. At 1 year of age, the patient was admitted to the hospital for recurrent bronchitis, otitis media, food refusal, mild diarrhea, and abdominal distension since weaning. A sweat chloride analysis excluded cystic fibrosis. At that time, the patient’s laboratory results showed increased C-reactive protein (139 mg/L; reference interval, <5 mg/L) and moderate leukocytosis (14.6 × 109/L; reference interval, 4.5–13.5 × 109/L). Values for all other v…

Evaluation of a new pooling strategy based on leukocyte count for rapid quantification of allele frequencies.

2007

Abstract Background: Allele frequencies of single-nucleotide polymorphisms (SNPs) can be quantified from DNA pools. The conventional preparation of DNA pools requires DNA isolation and quantification for each blood sample. We hypothesized that pooling of whole blood samples according to their leukocyte count, which determines DNA content, would be as reliable as the conventional pooling method but much less tedious to perform. Methods: We collected 100 whole blood samples and measured the leukocyte count. Samples were frozen until further use. After thawing, pools were generated by combining aliquots containing an equal number of leukocytes. In parallel, DNA was extracted from another aliqu…

Determination of globotriaosylceramide in plasma and urine by mass spectrometry

2009

Abstract Background: Fabry disease is an X-chromosomally inherited lysosomal storage disorder leading to accumulation of glycosphingolipids, mainly globotriaosylceramide (ceramide-trihexoside, Gb3). Concentrations of Gb3 in plasma and urine have been used to diagnose Fabry disease and to monitor enzyme replacement therapy with recombinant α-galactosidase. Methods: Gb3 was purified from plasma or urine by combined liquid extraction/protein precipitation and solid-phase extraction, and was detected by flow-injection analysis electrospray mass spectrometry (MS) using multi-reaction-monitoring. Calibration was performed via standard addition using C17-Gb3 as internal standard. The most abundant…

A novel approach to CFTR mutation testing by pyrosequencing-based assay panels adapted to ethnicities.

2009

Abstract Background: Cystic fibrosis (CF) is a common autosomal recessive genetic disorder caused by a variety of sequence alterations in the CFTR gene [cystic fibrosis transmembrane conductance regulator (ATP-binding cassette sub-family C, member 7)]. Because the relative prevalence of mutations strongly depends on the ethnic background, first-level testing of CF as defined by recent consensus recommendations ought to be adaptable to the ethnicity of patients. Methods: We therefore developed and implemented a diagnostic approach to first-level testing for CF based on published mutation frequencies and Pyrosequencing (PSQ) technology that we complemented with standard procedures of mutation…

Multicenter validation study for the certification of a CFTR gene scanning method using next generation sequencing technology.

2018

AbstractBackground:Many European laboratories offer molecular genetic analysis of theCFTRgene using a wide range of methods to identify mutations causative of cystic fibrosis (CF) and CFTR-related disorders (CFTR-RDs). Next-generation sequencing (NGS) strategies are widely used in diagnostic practice, and CE marking is now required for most in vitro diagnostic (IVD) tests in Europe. The aim of this multicenter study, which involved three European laboratories specialized in CF molecular analysis, was to evaluate the performance of Multiplicom’s CFTR MASTR Dx kit to obtain CE-IVD certification.Methods:A total of 164 samples, previously analyzed with well-established “reference” methods for t…

Abstract 18540: Heme Oxygenase 1 Activity and Expression Suppresses a Proinflammatory Phenotype in Monocytes and Correlates With Endothelial Function…

2014

Background: Heme oxygenase-1 (HO-1) confers protection to the vasculature and suppresses inflammatory properties of monocytes and macrophages. It is unclear how HO-1 activity and expression determine the extent of vascular dysfunction in mice and humans. Methods and results: Decreasing HO activity was parallelled by decreasing aortic HO-1, eNOS and phospho-eNOS (ser1177) protein expression in HO-1 deficient mice, whereas aortic expression of nox2 showed a stepwise increase in HO-1+/- and HO-1-/- mice as compared to HO-1+/+ controls. Aortic superoxide formation increased depending on the extent of HO-1 deficiency and was blunted by the PKC inhibitor chelerythrine, indicating activation of t…

Evidence for the utility of cfDNA plasma concentrations to predict disease severity in COVID-19

2021

AbstractCOVID-19 is a pandemic caused by the highly infective SARS-CoV-2. There is a need for biomarkers not only for overall prognosis but also for predicting the response to treatments and thus for improvements in the clinical management of patients with COVID-19. Circulating cell-free DNA (cfDNA) has emerged as a promising biomarker in the assessment of various disease conditions. The aim of this retrospective and observational pilot study was to examine the potential value of cfDNA plasma concentrations as a correlative biomarker in hospitalized COVID-19 patients. Lithium-Heparin plasma samples were obtained from twenty-one COVID-19 patients during hospitalization in the University Medi…

Eleven Relapses in a Cohort of 78 Patients with Immune Thrombotic Thrombocytopenic Purpura (iTTP): Data from the German TTP-Registry

2019

Alterations in lipid, carbohydrate and iron metabolism in patients with non-alcoholic steatohepatitis (NASH) and metabolic syndrome

2010

NASH (non-alcoholic steatohepatitis) is considered the hepatic manifestation of the metabolic syndrome (MS). We aimed to analyze lipid, carbohydrate, and iron metabolism in NASH.37 patients with MS (17 M/20 F, 51+/-15 years), elevated transaminases; 25 patients had histologically proven NASH (NAS score≥5), 12 patients had toxic background (nonNASH). 37 age, sex, BMI-matched healthy controls. Lipid variables, LDL-subfractions, iron, ferritin, transferrin (T), transferrin saturation (TS), and hepcidin (H) were measured in patients/controls. Oral glucose tolerance tests were performed.NASH patients with steatosis gr. 2 and 3 (33% hepatic fat) had higher sd-LDL (mg/dl) concentrations than patie…

Head and neck paragangliomas: Report of 175 patients (1989-2010)

2011

Attention of the otorhinolaryngologist needs to be drawn to the versatile aspects of head and neck paragangliomas (PGLs).This study is a retrospective, nonrandomized clinical study of all 175 individuals with PGLs treated in our department between 1989 and 2010. A genetic analysis was performed on 86 patients.The 175 patients presented 224 head and neck PGLs as well as 2 thyroid papillary carcinomas. Genetic analysis resulted in 1 patient positive for a von Hippel-Lindau (VHL) gene mutation and 34 for succinate dehydrogenase (SDH) gene mutations (22 SDHD, 7 SDHC, and 5 SDHB), 12 of the latter carrying a novel mutation. Thirty-three patients (18.9%) had multiple PGLs and 11 patients (6.3%) h…

Severe High Molecular Weight Kininogen (HK) Deficiency: Clinical Characteristics, Deficiency-Causing KNG1 Variants in Reported and New Cases, and Est…

2021

Abstract Background: Severe high molecular weight kininogen (HK) deficiency is an autosomal recessive defect of the contact system caused by mutations in KNG1. Limited scientific interest in HK deficiency due to the rarity of the seemingly asymptomatic condition may increase, as HK, the precursor of bradykinin, is now discussed as a therapeutic target e.g. in hereditary angioedema. Aims: We provide a comprehensive analysis of the diagnostic, clinical, and genetic features of HK deficiency and estimate its frequency. Methods: We identified a new case of HK deficiency, systematically review the literature, conduct new genetic studies of reported cases, and comprehensively analyze the clinical…

Severe plasma prekallikrein deficiency : clinical characteristics, novel KLKB1 mutations, and estimated prevalence

2020

BACKGROUND Severe plasma prekallikrein (PK) deficiency is an autosomal-recessive defect characterized by isolated activated partial thromboplastin time prolongation. To date, no comprehensive methodologically firm analysis has investigated the diagnostic, clinical, and genetic characteristics of PK deficiency, and its prevalence remains unknown. PATIENTS/METHODS We described new families with PK deficiency, retrieved clinical and laboratory information of cases systematically searched in the (gray) literature, and collected blood of these cases for complementary analyses. The Genome Aggregation Database (gnomAD) and the population-based Gutenberg Health Study served to study the prevalence …

Quantification of the Fabry marker lysoGb3 in human plasma by tandem mass spectrometry

2011

Morbus Fabry is a hereditary metabolic disorder with low prevalence and late clinical manifestation. A defect in the α-galactosidase gene leads to lysosomal accumulation of the glycolipid globotriaosylceramide (Gb3). Gb3 may be used for monitoring of enzyme replacement therapy (ERT), but diagnostic sensitivity is limited. Recently, globotriaosylsphingosine (lysoGb3) was introduced as a promising new marker with significantly better sensitivity. For Fabry diagnosis, clinical studies and possible therapy monitoring, we established a fast and reliable LC-MS/MS assay for quantification of lysoGb3 in human plasma. Protein precipitation and glycolipid extraction from EDTA plasma was performed usi…

Alterations in Lipid and Carbohydrate Metabolism in Patients with Classic Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency

2009

&lt;i&gt;Background:&lt;/i&gt; Classic 21-hydroxylase deficiency (21HD) presents some traits of the metabolic syndrome. &lt;i&gt;Aim:&lt;/i&gt; To characterize discrete alterations of lipid and carbohydrate metabolism in children and young adults with classic 21HD, which could predict early atherogenesis. &lt;i&gt;Patients and Methods:&lt;/i&gt; Twenty-seven Caucasian patients with classic 21HD (4–31 years); 27 sex-, age- and BMI-matched controls. Clinical parameters, hormonal status and genotype were assessed in all patients. Lipid parameters, including relative (%) and absolute (mg/dl) small-dense low-density lipoproteins subfractions (sd-LDL) were measured in patients and controls. Oral …

Distribution of HOMA-IR in a population-based cohort and proposal for reference intervals

2021

Abstract Objectives Insulin resistance (IR) is a hallmark of type 2 diabetes mellitus (DM). The homeostatic model assessment of insulin resistance (HOMA-IR) provides an estimate for IR from fasting glucose and insulin serum concentrations. The aim of this study was to obtain a reference interval for HOMA-IR for a specific insulin immunoassay. Methods The Gutenberg Health Study (GHS) is a population-based, prospective, single-center cohort study in Germany with 15,030 participants aged 35–74 years. Fasting glucose, insulin, and C-peptide were available in 10,340 participants. HOMA-IR was calculated in this group and three reference subgroups with increasingly more stringent inclusion criteri…

Comment on “Worldwide Distribution of PK Deficiency: the Defect Seems Mainly Concentrated in West African Countries and the United States.”

2021

The CFTR associated protein CAP70 interacts with the apical Cl-/HCO3- exchanger DRA in rabbit small intestinal mucosa.

2005

DRA (down regulated in adenoma) is an intestinal anion exchanger, acting in parallel with NHE3 to facilitate ileal and colonic NaCl absorption. Furthermore it is involved in small intestinal bicarbonate secretion. Because DRA has a PDZ interaction motif, which may influence its properties, we searched for DRA-interacting PDZ adapter proteins in the small intestine. Using an overlay assay with the recombinant DRA C-terminus as a ligand, a 70 kDa protein was labeled, which was restricted to the brush border membrane in rabbit duodenal and ileal mucosa and was not detected in the colon. Destruction of the C-terminal PDZ interaction motif abolished this band, suggesting a specific protein-prote…

Genetics and Beyond – The Transcriptome of Human Monocytes and Disease Susceptibility

2010

BACKGROUND: Variability of gene expression in human may link gene sequence variability and phenotypes; however, non-genetic variations, alone or in combination with genetics, may also influence expression traits and have a critical role in physiological and disease processes. METHODOLOGY/PRINCIPAL FINDINGS: To get better insight into the overall variability of gene expression, we assessed the transcriptome of circulating monocytes, a key cell involved in immunity-related diseases and atherosclerosis, in 1,490 unrelated individuals and investigated its association with >675,000 SNPs and 10 common cardiovascular risk factors. Out of 12,808 expressed genes, 2,745 expression quantitative trait …

Integrating genome-wide genetic variations and monocyte expression data reveals trans-regulated gene modules in humans.

2011

One major expectation from the transcriptome in humans is to characterize the biological basis of associations identified by genome-wide association studies. So far, few cis expression quantitative trait loci (eQTLs) have been reliably related to disease susceptibility. Trans-regulating mechanisms may play a more prominent role in disease susceptibility. We analyzed 12,808 genes detected in at least 5% of circulating monocyte samples from a population-based sample of 1,490 European unrelated subjects. We applied a method of extraction of expression patterns—independent component analysis—to identify sets of co-regulated genes. These patterns were then related to 675,350 SNPs to identify maj…

Malignant paraganglioma caused by a novel germline mutation of the succinate dehydrogenase D-gene--a case report.

2008

Background Paragangliomas of the head and neck are rare, mostly benign tumors. Approximately 10% to 15% of paragangliomas are caused by mutations in the succinate dehydrogenase (SDH) genes B, C, or D. These are often multifocal as part of paraganglioma syndromes and hormone secreting, and malignant particularly associated with mutations in SDHB. Methods and Results A 29-year-old man was seen with recurrent paraganglioma. The patient's father reportedly suffered from bilateral carotid body tumors. Imaging studies showed metastases in both lungs and the liver. There was no increased hormone production by the tumor. Sequence analysis of the SDH genes revealed a novel C to T nonsense mutation i…

Invited commentary to: ADAMTS13 deficiency is associated with abnormal distribution of von Willebrand factor multimers in patients with COVID-19 by T…

2021

Hereditary angioedema cosegregating with a novel kininogen 1 gene mutation changing the N‐terminal cleavage site of bradykinin

2019

Head and Neck Paragangliomas

2016

Head and neck paragangliomas are highly vascularized neuroendocrine tumors derived from the extra-adrenal paraganglia of the autonomic nervous system. These tumors may occur either sporadically or in the context of a hereditary familial tumor syndrome, and multifocal presentations are observed, particularly in hereditary cases. Hereditary paragangliomas are mostly caused by mutations in the succinate dehydrogenase complex genes. Early imaging, with ultrasonography of the neck and magnetic resonance imaging (MRI) of the skull base, is essential for localizing and assessing the extent of the tumor, as well as for precise planning of the treatment approach. Views regarding the treatment of cho…

Risk stratification of normotensive pulmonary embolism: prognostic impact of copeptin

2015

The prognostic value of copeptin, the C-terminal fragment of the precursor protein of vasopressin which is released upon stress, and hypotension in pulmonary embolism is unknown, especially if combined with biomarkers reflecting different pathophysiological axes such as myocardial injury (high-sensitivity troponin T (hsTnT)) and stretch (N-terminal pro-brain natriuretic peptide (NT-proBNP)).We prospectively studied 268 normotensive pulmonary embolism patients included in a single-centre cohort study.Patients with an adverse 30-day outcome (5.6%) had higher copeptin levels than patients with a favourable course (median (interquartile range) 51.8 (21.6–90.8) versus 13.2 (5.9–39.3) pmol·L−1; p…

Impact of Glutathione Peroxidase-1 Deficiency on Macrophage Foam Cell Formation and Proliferation: Implications for Atherogenesis

2013

Clinical and experimental evidence suggests a protective role for the antioxidant enzyme glutathione peroxidase-1 (GPx-1) in the atherogenic process. GPx-1 deficiency accelerates atherosclerosis and increases lesion cellularity in ApoE(-/-) mice. However, the distribution of GPx-1 within the atherosclerotic lesion as well as the mechanisms leading to increased macrophage numbers in lesions is still unknown. Accordingly, the aims of the present study were (1) to analyze which cells express GPx-1 within atherosclerotic lesions and (2) to determine whether a lack of GPx-1 affects macrophage foam cell formation and cellular proliferation. Both in situ-hybridization and immunohistochemistry of l…

6-18F-Fluoro-l-Dihydroxyphenylalanine Positron Emission Tomography Is Superior to123I-Metaiodobenzyl-Guanidine Scintigraphy in the Detection of Extra…

2010

Context: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) may be better detected by 18F-fluorodihydroxyphenylalanine-positron emission tomography (FDOPA-PET) than 123I-metaiodobenzyl-guanidine (123-I-MIBG) scintigraphy. Objective: The objective of the study was to correlate functional imaging results with immunohistochemical, molecular-genetic, and biochemical findings. Design and Setting: Thirty consecutive patients with suspected PHEO/PGL presenting at a tertiary referral centre were investigated in a prospective study. Patients: Twenty-five patients had confirmed PHEO/PGL. Thirteen of 25 patients had a hereditary PHEO/PGL syndrome (two multiple endocrine neoplasia II, six succinate de…

Deficiency of glutathione peroxidase-1 accelerates the progression of atherosclerosis in apolipoprotein E-deficient mice.

2007

Background— We have recently demonstrated that activity of red blood cell glutathione peroxidase-1 is inversely associated with the risk of cardiovascular events in patients with coronary artery disease. The present study analyzed the effect of glutathione peroxidase-1 deficiency on atherogenesis in the apolipoprotein E-deficient mouse. Methods and Results— Female apolipoprotein E-deficient mice with and without glutathione peroxidase-1 deficiency were placed on a Western-type diet for another 6, 12, or 24 weeks. After 24 weeks on Western-type diet, double-knockout mice (GPx-1 −/− ApoE −/− ) developed significantly more atherosclerosis than control apolipoprotein E-deficient mice. Moreover…

Open ADAMTS13, induced by antibodies, is a biomarker for subclinical immune-mediated thrombotic thrombocytopenic purpura

2020

Recently, we showed that ADAMTS13 circulates in an open conformation during the acute phase of immune-mediated thrombotic thrombocytopenic purpura (iTTP). Although the cause of this conformational change remains elusive, ADAMTS13 is primarily closed in iTTP patients in remission with ADAMTS13 activity >50% and undetectable anti-ADAMTS13 autoantibodies, as well as after rituximab treatment, suggesting a role for anti-ADAMTS13 autoantibodies. Therefore, immunoglobulin G from 18 acute iTTP patients was purified and added to closed ADAMTS13 in healthy donor plasma. This resulted in open ADAMTS13 in 14 of 18 (78%) samples, proving that anti-ADAMTS13 autoantibodies can induce an open ADAMTS13 con…

Chronically Elevated Interleukin-6 Disturbs the Coagulation Cascade in Mice

2021

Abstract Introduction: Pro-inflammatory cytokines play an essential role as activators of the hemostatic system and in the regulation of physiological antithrombotic mechanisms. Interleukin-6 (IL-6) influences platelet production and platelet activation. It was associated with accelerated clotting and intravascular coagulation in tissue factor (TF)-driven murine thrombosis models. However, the precise role of myeloid cell-derived IL-6 on thrombosis formation and the hemostatic system is still unknown. Methods and Results: To better understand the role of IL-6 in thrombosis and the hemostatic system, we developed a new mouse strain with Cre-recombinase driven constitutive IL-6 expression spe…

No Evidence for Classic Thrombotic Microangiopathy in COVID-19

2021

Background: Coronavirus disease-2019 (COVID-19) triggers systemic infection with involvement of the respiratory tract. There are some patients developing haemostatic abnormalities during their infection with a considerably increased risk of death. Materials and Methods: Patients (n = 85) with SARS-CoV-2 infection attending the University Medical Center, Mainz, from 3 March to 15 May 2020 were retrospectively included in this study. Data regarding demography, clinical features, treatment and laboratory parameters were analyzed. Twenty patients were excluded for assessment of disseminated intravascular coagulation (DIC) and thrombotic microangiopathy (TMA) due to lack of laboratory data. Resu…

Detection and Differential Diagnosis of Prekallikrein Deficiency: Genetic Study of New Families and Systematic Review of the Literature

2018

Abstract Introduction. Prekallikrein (PK) and high-molecular-weight kininogen (HK) deficiencies are ultra-rare, autosomal-recessive defects of the contact system caused by biallelic mutations in the KLKB1 and KNG1 genes, respectively. Since affected subjects do not manifest a bleeding phenotype, a correct diagnosis is essential to prevent the administration of prohemostatic agents or plasma and to avoid delay of surgery. We describe a new case of PK deficiency identified at UMC Mainz. In addition, we performed a systematic review of the literature in order to i) collect blood material for genetic studies of reported PK deficient cases lacking this information, and ii) perform a comprehensiv…

Anti-ADAMTS13 autoantibody profiling in patients with immune-mediated thrombotic thrombocytopenic purpura.

2021

Anti-A Disintegrin and Metalloproteinase with a ThromboSpondin type 1 motif, member 13 (ADAMTS13) autoantibodies cause a severe ADAMTS13 deficiency in immune-mediated thrombotic thrombocytopenic purpura (iTTP). ADAMTS13 consists of a metalloprotease (M), a disintegrin-like (D) domain, 8 thrombospondin type 1 repeats (T1-T8), a cysteine-rich (C), a spacer (S), and 2 CUB domains (CUB1-2). We recently developed a high-throughput epitope mapping assay based on small, nonoverlapping ADAMTS13 fragments (M, DT, CS, T2-T5, T6-T8, CUB1-2). With this assay, we performed a comprehensive epitope mapping using 131 acute-phase samples and for the first time a large group of remission samples (n = 50). Ne…