The GNE gene encodes an enzyme that initiates and regulates the biosynthesis of N-acetylneuramini... more The GNE gene encodes an enzyme that initiates and regulates the biosynthesis of N-acetylneuraminic acid, a precursor of sialic acids. GNE mutations are classically associated with Nonaka myopathy and sialuria, following an autosomal recessive and autosomal dominant inheritance pattern. Reports show that single GNE variants cause severe thrombocytopenia without muscle weakness. Using panel sequencing, we identified two novel compound heterozygous variants in GNE in a young girl with life-threatening bleedings, severe congenital thrombocytopenia, and a platelet secretion defect. Both variants are located in the nucleotide-binding site of the N-acetylmannosamin kinase domain of GNE. Lectin array showed decreased α-2,3-sialylation on platelets, consistent with loss of sialic acid synthesis and indicative of rapid platelet clearance. Hematopoietic stem cell transplantation (HSCT) normalized platelet counts. This is the first report of an HSCT in a patient with an inherited GNE defect lea...
version. There may also be differences in the quality of the graphics. When papers do appear in p... more version. There may also be differences in the quality of the graphics. When papers do appear in print, they will be removed from this feature and grouped with other papers in an issue. Biol Chem 'Just Accepted' Papers are citable; the online publication date is indicated on the Table of Contents page, and the article' s Digital Object I dentifi er (DOI), a unique identifi er for intellectual property in the digital environment (e.g., 10.1515/hsz-2011-xxxx), is shown at the top margin of the title page. Once an article is published as Biol Chem 'Just Accepted' Paper (and before it is published in its fi nal form), it should be cited in other articles by indicating author list, title and DOI. After a paper is published in Biol Chem 'Just Accepted' Paper form, it proceeds through the normal production process, which includes copy editing, typesetting and proofreading. The edited paper is then published in its fi nal form in a regular print and online issue of Biol Chem. At this time, the Biol Chem 'Just Accepted' Paper version is replaced on the journal Web site by the fi nal version of the paper with the same DOI as the Biol Chem 'Just Accepted' Paper version. Disclaimer Biol Chem 'Just Accepted' Papers have undergone the complete peer-review process. However, none of the additional editorial preparation, which includes copy editing, typesetting and proofreading, has been performed. Therefore, there may be errors in articles published as Biol Chem 'Just Accepted' Papers that will be corrected in the fi nal print and online version of the Journal. Any use of these articles is subject to the explicit understanding that the papers have not yet gone through the full quality control process prior to advanced publication.
The GATA1 transcription factor is essential for normal erythropoiesis and megakaryocytic differen... more The GATA1 transcription factor is essential for normal erythropoiesis and megakaryocytic differentiation. Germline GATA1 pathogenic variants in the N-terminal zinc finger (N-ZF) are typically associated with X-linked thrombocytopenia, platelet dysfunction, and dyserythropoietic anemia. A few variants in the C-terminal ZF (C-ZF) domain are described with normal platelet count but altered platelet function as the main characteristic. Independently performed molecular genetic analysis identified a novel hemizygous variant (c.865C>T, p.H289Y) in the C-ZF region of GATA1 in a German patient and in a Spanish patient. We characterized the bleeding and platelet phenotype of these patients and compared these findings with the parameters of two German siblings carrying the likely pathogenic variant p.D218N in the GATA1 N-ZF domain. The main difference was profound thrombocytopenia in the brothers carrying the p.D218N variant compared to a normal platelet count in patients carrying the p.H2...
Hermansky-Pudlak syndrome (HPS), a rare heterogeneous autosomal recessive disorder, is characteri... more Hermansky-Pudlak syndrome (HPS), a rare heterogeneous autosomal recessive disorder, is characterized by oculocutaneous albinism (OCA) and a bleeding diathesis due to a defect regarding melanosomes and platelet delta (δ)-granule secretion. Interestingly, patients with HPS type 2 (HPS-2) or HPS type 10 (HPS-10) present additionally with an immunological defect. We investigated three patients (IP1, IP2, and IP3) who suffer from a bleeding diathesis. Platelet aggregometry showed impaired platelet function and flow cytometry revealed a severely reduced platelet CD63 expression hinting to either a defect of platelet delta granule secretion or a decreased number of delta granules in these patients. However, only IP3 presents with an apparent OCA. We performed panel sequencing and identified a homozygous deletion of exon 6 in DTNBP1 for IP3. Western analysis confirmed the absence of the encoded protein dysbindin confirming the diagnosis of HPS-7. Interestingly, this patient reported additio...
Bernard-Soulier syndrome (BSS) is a rare, autosomal recessive inherited bleeding disorder associa... more Bernard-Soulier syndrome (BSS) is a rare, autosomal recessive inherited bleeding disorder associated with thrombocytopenia, thrombocytopathy and giant platelets. BSS is caused by genetic alterations of the glycoprotein (GP) Ib/V/IX complex. We report on a large Swiss family of whom four family members suffer from BSS. Here, a homozygous missense mutation in position 1829 (A®G) of the GPIX gene constituting a N45S substitution is the cause for the bleeding symptoms. A total of 38 family members within two generations were analyzed regarding the N45S mutation by DNA sequencing and restriction fragment length polymorphism. The laboratory parameters which are characteristically for BSS such as platelet count, platelet volume and the expression of CD42a (GPIX), CD42b (GPIb?) and CD41 (GPIIb) were measured for all 38 individuals. The four homozygous patients showed bleeding symptoms, thrombocytopenia and giant platelets. In these patients, the expression of CD42a (GPIX), CD42b (GPIb?) was...
Griscelli syndrome (GS) was diagnosed in a 2-year old patient with oculocutaneous albinism and im... more Griscelli syndrome (GS) was diagnosed in a 2-year old patient with oculocutaneous albinism and immunodeficiency, but sequencing of RAB27a only revealed a heterozygous mutation. Due to impaired NK and T cell cytotoxicity implying a high risk of developing hemophagocytic lymphohistiocytosis (HLH), he was prepared for hematopoetic stem cell transplantation (HSCT). Unexpectedly, a severe bleeding episode occurred that led to the demonstration of disturbed platelet aggregation, reduced platelet dense granules and impaired platelet degranulation. In combination with neutropenia, this suggested the diagnosis of Hermansky-Pudlak syndrome Type II (HPSII) and a novel homozygous mutation in AP3B1 was detected. None of the three reported HPSII patients had developed HLH and our patient seroconverted to EBV without clinical symptoms. HSCT was therefore withheld, G-CSF therapy was initiated and prevented further bacterial infections. At three years of age, however, the patient developed fulminant...
Septins (Septs) are a widely expressed protein family of 13 mammalian members, recognized as a un... more Septins (Septs) are a widely expressed protein family of 13 mammalian members, recognized as a unique component of the cytoskeleton. In human platelets, we previously described that SEPT4 and SEPT8 are localized surrounding α-granules and move to the platelet surface after activation, indicating a possible role in platelet physiology. In this study, we investigated the impact of Sept8 on platelet function in vitro using Sept8-deficient mouse platelets. Deletion of Sept8 in mouse platelets caused a pronounced defect in activation of the fibrinogen receptor integrin αIIbβ3, α-granule exocytosis, and aggregation, especially in response to the glycoprotein VI agonist convulxin. In contrast, δ-granule and lysosome exocytosis of Sept8-deficient platelets was comparable to wild-type platelets. Sept8-deficient platelet binding to immobilized fibrinogen under static conditions was diminished and spreading delayed. The procoagulant activity of Sept8-deficient platelets was reduced in response...
Gray platelet syndrome (GPS) is a rare recessive disorder caused by variants in NBEAL2 and charac... more Gray platelet syndrome (GPS) is a rare recessive disorder caused by variants in NBEAL2 and characterized by bleeding symptoms, the absence of platelet ɑ-granules, splenomegaly and bone marrow (BM) fibrosis. Due to its rarity, it has been difficult to fully understand the pathogenic processes that lead to these clinical sequelae. To discern the spectrum of pathological features, we performed a detailed clinical genotypic and phenotypic study of 47 GPS patients. We identified 33 new causal variants in NBEAL2. Our GPS patient cohort exhibited known phenotypes, including macro-thrombocytopenia, BM fibrosis, megakaryocyte emperipolesis of neutrophils, splenomegaly, and elevated serum vitamin B12 levels. We also observed novel clinical phenotypes; these include reduced leukocyte counts and increased presence of autoimmune disease and positive autoantibodies. There were widespread differences in the transcriptome and proteome of GPS platelets, neutrophils, monocytes, and CD4-lymphocytes. P...
Patients diagnosed with pseudohypoparathyroidism type Ia (PHP Ia) suffer from hormonal resistance... more Patients diagnosed with pseudohypoparathyroidism type Ia (PHP Ia) suffer from hormonal resistance and abnormal postural features, in a condition classified as Albright hereditary osteodystrophy (AHO) syndrome. This syndrome is linked to a maternally inherited mutation in the GNAS complex locus, encoding for the GTPase subunit Gsα. Here, we investigated how platelet phenotype and omics analysis can assist in the often difficult diagnosis. By coupling to the IP receptor, Gsα induces platelet inhibition via adenylyl cyclase and cAMP-dependent protein kinase A (PKA). In platelets from seven patients with suspected AHO, one of the largest cohorts examined, we studied the PKA-induced phenotypic changes. Five patients with a confirmed GNAS mutation, displayed impairments in Gsα-dependent VASP phosphorylation, aggregation, and microfluidic thrombus formation. Analysis of the platelet phosphoproteome revealed 2,516 phosphorylation sites, of which 453 were regulated by Gsα-PKA. Common changes...
Abstract Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder caused by defects... more Abstract Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder caused by defects in 10 human HPS genes, characterized by oculocutaneous albinism (OCA) and bleeding diathesis associated to platelet δ-storage pool defect (SPD). We report a case of 4-year-old boy from non-consanguineous parents with OCA and negative personal and familiar hemorrhagic history, referred to us for severe bleeding after mild trauma. His platelet function, studied by lumi-aggregometry, showed normal first wave of aggregation in response to exogenous agonists and impaired second wave with defective ATP release. This, in combination with impaired platelet δ-granules content (serotonin, ATP, ADP) and the OCA phenotype suggested the HPS diagnosis. HPS3 sequencing revealed a novel pathogenic homozygous variant (NM_032383.4:c.7>T, p.Gln3*) resulting in a premature stop codon at the amino acid 3. Moreover, our report highlights the importance of evaluating platelet function in children with OCA without bleeding diathesis to identify HPS early and prevent bleeding complications.
The European Hematology Association (EHA) Roadmap for European Hematology Research highlights maj... more The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at Euro 23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary wa...
Die Beiträge der Rubrik "Fortbildung" sollen dem Wissenstand zur Facharztprüfung für den Pädiater... more Die Beiträge der Rubrik "Fortbildung" sollen dem Wissenstand zur Facharztprüfung für den Pädiater entsprechen und zugleich dem Facharzt als Repetitorium dienen. Die Rubrik beschränkt sich auf klinisch gesicherte Aussagen zum Thema.
Spinal cord infarction from anterior spinal cord syndrome (ASAS) in children is a rare pathology ... more Spinal cord infarction from anterior spinal cord syndrome (ASAS) in children is a rare pathology and comprises the following clinical symptoms: sudden onset of pain and flaccid para- or tetraparesis, bladder dysfunction, and dissociated sensory loss with impairment of pain and temperature perception. Deep sensibility is not affected. A 13-year-old male patient presented to our emergency department with a bilateral leg weakness. 1 week before, he had suffered a leg strain in a Taekwondo-fight from which he recovered completely. On physical examination our patient's legs were in flaccid paralysis, tone was decreased and he had dissociated sensory loss and acute retention of urine. Blood count, ESR, electrolytes, serologic tests for various pathogens and CSF examination all were normal. However, tests for values of an acute endothelial lesion were increased and he was a homozygous carrier of MTHFR-polymorphism. MRI performed on the day of admission was normal but showed dramatic changes 2 days later with increased signal intensity in the ventral aspect of the spinal cord, characteristic for an ASAS. Treatment included highdose methylprednisolone, a suprapubic bladder catheter, sufficient anticoagulation and a rapid transfer to a rehabilitation centre. We assume that a combination of the patient's prothrombotic risk factor (MTHFR-polymorphism with elevated homocysteine levels) and his trauma in the taekwondo-fight with consecutive vessel injury caused an occlusion of the artery by late emboli or a growing thrombus.
Mucociliary clearance of the airways is accomplished by cilia-mediated laminar mucus flow along t... more Mucociliary clearance of the airways is accomplished by cilia-mediated laminar mucus flow along the planar epithelial surface. Maintenance of the highly specific architecture of the ciliated airway epithelium with columnar-shaped epithelial cells and tightening of the epithelial barrier is mainly attributed to the F-actin cytoskeleton. Recently, members of the highly conserved family of septin proteins have been shown to play crucial roles in ciliated tissue. These GTP-binding proteins form hetero-oligomeric complexes and assemble higher-order cytoskeletal structures such as filaments, bundles and ring-like structures such as a membrane diffusion barrier at the ciliary base. Here we analyzed the subcellular and sub-ciliary localization of various septin proteins by immunofluorescence imaging of airway epithelial cells. In addition to cytoplasmic localization we found that septins are either enriched at the apical cell cortex including the ciliary bases (septin-2, -4, -6, and -7), or...
Critically ill COVID-19 patients suffer from thromboembolic as well as bleeding events. Endotheli... more Critically ill COVID-19 patients suffer from thromboembolic as well as bleeding events. Endothelial dysfunction, spiking of von Willebrand factor (vWF), and excessive cytokine signaling result in coagulopathy associated with substantial activation of plasmatic clotting factors. Thrombocytopenia secondary to extensive platelet activation is a frequent finding, but abnormal platelet dysfunction may also exist in patients with normal platelet counts. In this study, we performed analyses of platelet function and of von Willebrand factor in critically ill COVID-19 patients (n = 13). Platelet aggregometry was performed using ADP, collagen, epinephrin, and ristocetin. VWF and fibrinogen binding of platelets and CD62 and CD63 expression after thrombin stimulation were analyzed via flow cytometry. In addition, VWF antigen (VWF:Ag), collagen binding capacity (VWF:CB), and multimer analysis were performed next to routine coagulation parameters. All patients exhibited reduced platelet aggregati...
The GNE gene encodes an enzyme that initiates and regulates the biosynthesis of N-acetylneuramini... more The GNE gene encodes an enzyme that initiates and regulates the biosynthesis of N-acetylneuraminic acid, a precursor of sialic acids. GNE mutations are classically associated with Nonaka myopathy and sialuria, following an autosomal recessive and autosomal dominant inheritance pattern. Reports show that single GNE variants cause severe thrombocytopenia without muscle weakness. Using panel sequencing, we identified two novel compound heterozygous variants in GNE in a young girl with life-threatening bleedings, severe congenital thrombocytopenia, and a platelet secretion defect. Both variants are located in the nucleotide-binding site of the N-acetylmannosamin kinase domain of GNE. Lectin array showed decreased α-2,3-sialylation on platelets, consistent with loss of sialic acid synthesis and indicative of rapid platelet clearance. Hematopoietic stem cell transplantation (HSCT) normalized platelet counts. This is the first report of an HSCT in a patient with an inherited GNE defect lea...
version. There may also be differences in the quality of the graphics. When papers do appear in p... more version. There may also be differences in the quality of the graphics. When papers do appear in print, they will be removed from this feature and grouped with other papers in an issue. Biol Chem 'Just Accepted' Papers are citable; the online publication date is indicated on the Table of Contents page, and the article' s Digital Object I dentifi er (DOI), a unique identifi er for intellectual property in the digital environment (e.g., 10.1515/hsz-2011-xxxx), is shown at the top margin of the title page. Once an article is published as Biol Chem 'Just Accepted' Paper (and before it is published in its fi nal form), it should be cited in other articles by indicating author list, title and DOI. After a paper is published in Biol Chem 'Just Accepted' Paper form, it proceeds through the normal production process, which includes copy editing, typesetting and proofreading. The edited paper is then published in its fi nal form in a regular print and online issue of Biol Chem. At this time, the Biol Chem 'Just Accepted' Paper version is replaced on the journal Web site by the fi nal version of the paper with the same DOI as the Biol Chem 'Just Accepted' Paper version. Disclaimer Biol Chem 'Just Accepted' Papers have undergone the complete peer-review process. However, none of the additional editorial preparation, which includes copy editing, typesetting and proofreading, has been performed. Therefore, there may be errors in articles published as Biol Chem 'Just Accepted' Papers that will be corrected in the fi nal print and online version of the Journal. Any use of these articles is subject to the explicit understanding that the papers have not yet gone through the full quality control process prior to advanced publication.
The GATA1 transcription factor is essential for normal erythropoiesis and megakaryocytic differen... more The GATA1 transcription factor is essential for normal erythropoiesis and megakaryocytic differentiation. Germline GATA1 pathogenic variants in the N-terminal zinc finger (N-ZF) are typically associated with X-linked thrombocytopenia, platelet dysfunction, and dyserythropoietic anemia. A few variants in the C-terminal ZF (C-ZF) domain are described with normal platelet count but altered platelet function as the main characteristic. Independently performed molecular genetic analysis identified a novel hemizygous variant (c.865C>T, p.H289Y) in the C-ZF region of GATA1 in a German patient and in a Spanish patient. We characterized the bleeding and platelet phenotype of these patients and compared these findings with the parameters of two German siblings carrying the likely pathogenic variant p.D218N in the GATA1 N-ZF domain. The main difference was profound thrombocytopenia in the brothers carrying the p.D218N variant compared to a normal platelet count in patients carrying the p.H2...
Hermansky-Pudlak syndrome (HPS), a rare heterogeneous autosomal recessive disorder, is characteri... more Hermansky-Pudlak syndrome (HPS), a rare heterogeneous autosomal recessive disorder, is characterized by oculocutaneous albinism (OCA) and a bleeding diathesis due to a defect regarding melanosomes and platelet delta (δ)-granule secretion. Interestingly, patients with HPS type 2 (HPS-2) or HPS type 10 (HPS-10) present additionally with an immunological defect. We investigated three patients (IP1, IP2, and IP3) who suffer from a bleeding diathesis. Platelet aggregometry showed impaired platelet function and flow cytometry revealed a severely reduced platelet CD63 expression hinting to either a defect of platelet delta granule secretion or a decreased number of delta granules in these patients. However, only IP3 presents with an apparent OCA. We performed panel sequencing and identified a homozygous deletion of exon 6 in DTNBP1 for IP3. Western analysis confirmed the absence of the encoded protein dysbindin confirming the diagnosis of HPS-7. Interestingly, this patient reported additio...
Bernard-Soulier syndrome (BSS) is a rare, autosomal recessive inherited bleeding disorder associa... more Bernard-Soulier syndrome (BSS) is a rare, autosomal recessive inherited bleeding disorder associated with thrombocytopenia, thrombocytopathy and giant platelets. BSS is caused by genetic alterations of the glycoprotein (GP) Ib/V/IX complex. We report on a large Swiss family of whom four family members suffer from BSS. Here, a homozygous missense mutation in position 1829 (A®G) of the GPIX gene constituting a N45S substitution is the cause for the bleeding symptoms. A total of 38 family members within two generations were analyzed regarding the N45S mutation by DNA sequencing and restriction fragment length polymorphism. The laboratory parameters which are characteristically for BSS such as platelet count, platelet volume and the expression of CD42a (GPIX), CD42b (GPIb?) and CD41 (GPIIb) were measured for all 38 individuals. The four homozygous patients showed bleeding symptoms, thrombocytopenia and giant platelets. In these patients, the expression of CD42a (GPIX), CD42b (GPIb?) was...
Griscelli syndrome (GS) was diagnosed in a 2-year old patient with oculocutaneous albinism and im... more Griscelli syndrome (GS) was diagnosed in a 2-year old patient with oculocutaneous albinism and immunodeficiency, but sequencing of RAB27a only revealed a heterozygous mutation. Due to impaired NK and T cell cytotoxicity implying a high risk of developing hemophagocytic lymphohistiocytosis (HLH), he was prepared for hematopoetic stem cell transplantation (HSCT). Unexpectedly, a severe bleeding episode occurred that led to the demonstration of disturbed platelet aggregation, reduced platelet dense granules and impaired platelet degranulation. In combination with neutropenia, this suggested the diagnosis of Hermansky-Pudlak syndrome Type II (HPSII) and a novel homozygous mutation in AP3B1 was detected. None of the three reported HPSII patients had developed HLH and our patient seroconverted to EBV without clinical symptoms. HSCT was therefore withheld, G-CSF therapy was initiated and prevented further bacterial infections. At three years of age, however, the patient developed fulminant...
Septins (Septs) are a widely expressed protein family of 13 mammalian members, recognized as a un... more Septins (Septs) are a widely expressed protein family of 13 mammalian members, recognized as a unique component of the cytoskeleton. In human platelets, we previously described that SEPT4 and SEPT8 are localized surrounding α-granules and move to the platelet surface after activation, indicating a possible role in platelet physiology. In this study, we investigated the impact of Sept8 on platelet function in vitro using Sept8-deficient mouse platelets. Deletion of Sept8 in mouse platelets caused a pronounced defect in activation of the fibrinogen receptor integrin αIIbβ3, α-granule exocytosis, and aggregation, especially in response to the glycoprotein VI agonist convulxin. In contrast, δ-granule and lysosome exocytosis of Sept8-deficient platelets was comparable to wild-type platelets. Sept8-deficient platelet binding to immobilized fibrinogen under static conditions was diminished and spreading delayed. The procoagulant activity of Sept8-deficient platelets was reduced in response...
Gray platelet syndrome (GPS) is a rare recessive disorder caused by variants in NBEAL2 and charac... more Gray platelet syndrome (GPS) is a rare recessive disorder caused by variants in NBEAL2 and characterized by bleeding symptoms, the absence of platelet ɑ-granules, splenomegaly and bone marrow (BM) fibrosis. Due to its rarity, it has been difficult to fully understand the pathogenic processes that lead to these clinical sequelae. To discern the spectrum of pathological features, we performed a detailed clinical genotypic and phenotypic study of 47 GPS patients. We identified 33 new causal variants in NBEAL2. Our GPS patient cohort exhibited known phenotypes, including macro-thrombocytopenia, BM fibrosis, megakaryocyte emperipolesis of neutrophils, splenomegaly, and elevated serum vitamin B12 levels. We also observed novel clinical phenotypes; these include reduced leukocyte counts and increased presence of autoimmune disease and positive autoantibodies. There were widespread differences in the transcriptome and proteome of GPS platelets, neutrophils, monocytes, and CD4-lymphocytes. P...
Patients diagnosed with pseudohypoparathyroidism type Ia (PHP Ia) suffer from hormonal resistance... more Patients diagnosed with pseudohypoparathyroidism type Ia (PHP Ia) suffer from hormonal resistance and abnormal postural features, in a condition classified as Albright hereditary osteodystrophy (AHO) syndrome. This syndrome is linked to a maternally inherited mutation in the GNAS complex locus, encoding for the GTPase subunit Gsα. Here, we investigated how platelet phenotype and omics analysis can assist in the often difficult diagnosis. By coupling to the IP receptor, Gsα induces platelet inhibition via adenylyl cyclase and cAMP-dependent protein kinase A (PKA). In platelets from seven patients with suspected AHO, one of the largest cohorts examined, we studied the PKA-induced phenotypic changes. Five patients with a confirmed GNAS mutation, displayed impairments in Gsα-dependent VASP phosphorylation, aggregation, and microfluidic thrombus formation. Analysis of the platelet phosphoproteome revealed 2,516 phosphorylation sites, of which 453 were regulated by Gsα-PKA. Common changes...
Abstract Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder caused by defects... more Abstract Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder caused by defects in 10 human HPS genes, characterized by oculocutaneous albinism (OCA) and bleeding diathesis associated to platelet δ-storage pool defect (SPD). We report a case of 4-year-old boy from non-consanguineous parents with OCA and negative personal and familiar hemorrhagic history, referred to us for severe bleeding after mild trauma. His platelet function, studied by lumi-aggregometry, showed normal first wave of aggregation in response to exogenous agonists and impaired second wave with defective ATP release. This, in combination with impaired platelet δ-granules content (serotonin, ATP, ADP) and the OCA phenotype suggested the HPS diagnosis. HPS3 sequencing revealed a novel pathogenic homozygous variant (NM_032383.4:c.7>T, p.Gln3*) resulting in a premature stop codon at the amino acid 3. Moreover, our report highlights the importance of evaluating platelet function in children with OCA without bleeding diathesis to identify HPS early and prevent bleeding complications.
The European Hematology Association (EHA) Roadmap for European Hematology Research highlights maj... more The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at Euro 23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary wa...
Die Beiträge der Rubrik "Fortbildung" sollen dem Wissenstand zur Facharztprüfung für den Pädiater... more Die Beiträge der Rubrik "Fortbildung" sollen dem Wissenstand zur Facharztprüfung für den Pädiater entsprechen und zugleich dem Facharzt als Repetitorium dienen. Die Rubrik beschränkt sich auf klinisch gesicherte Aussagen zum Thema.
Spinal cord infarction from anterior spinal cord syndrome (ASAS) in children is a rare pathology ... more Spinal cord infarction from anterior spinal cord syndrome (ASAS) in children is a rare pathology and comprises the following clinical symptoms: sudden onset of pain and flaccid para- or tetraparesis, bladder dysfunction, and dissociated sensory loss with impairment of pain and temperature perception. Deep sensibility is not affected. A 13-year-old male patient presented to our emergency department with a bilateral leg weakness. 1 week before, he had suffered a leg strain in a Taekwondo-fight from which he recovered completely. On physical examination our patient's legs were in flaccid paralysis, tone was decreased and he had dissociated sensory loss and acute retention of urine. Blood count, ESR, electrolytes, serologic tests for various pathogens and CSF examination all were normal. However, tests for values of an acute endothelial lesion were increased and he was a homozygous carrier of MTHFR-polymorphism. MRI performed on the day of admission was normal but showed dramatic changes 2 days later with increased signal intensity in the ventral aspect of the spinal cord, characteristic for an ASAS. Treatment included highdose methylprednisolone, a suprapubic bladder catheter, sufficient anticoagulation and a rapid transfer to a rehabilitation centre. We assume that a combination of the patient's prothrombotic risk factor (MTHFR-polymorphism with elevated homocysteine levels) and his trauma in the taekwondo-fight with consecutive vessel injury caused an occlusion of the artery by late emboli or a growing thrombus.
Mucociliary clearance of the airways is accomplished by cilia-mediated laminar mucus flow along t... more Mucociliary clearance of the airways is accomplished by cilia-mediated laminar mucus flow along the planar epithelial surface. Maintenance of the highly specific architecture of the ciliated airway epithelium with columnar-shaped epithelial cells and tightening of the epithelial barrier is mainly attributed to the F-actin cytoskeleton. Recently, members of the highly conserved family of septin proteins have been shown to play crucial roles in ciliated tissue. These GTP-binding proteins form hetero-oligomeric complexes and assemble higher-order cytoskeletal structures such as filaments, bundles and ring-like structures such as a membrane diffusion barrier at the ciliary base. Here we analyzed the subcellular and sub-ciliary localization of various septin proteins by immunofluorescence imaging of airway epithelial cells. In addition to cytoplasmic localization we found that septins are either enriched at the apical cell cortex including the ciliary bases (septin-2, -4, -6, and -7), or...
Critically ill COVID-19 patients suffer from thromboembolic as well as bleeding events. Endotheli... more Critically ill COVID-19 patients suffer from thromboembolic as well as bleeding events. Endothelial dysfunction, spiking of von Willebrand factor (vWF), and excessive cytokine signaling result in coagulopathy associated with substantial activation of plasmatic clotting factors. Thrombocytopenia secondary to extensive platelet activation is a frequent finding, but abnormal platelet dysfunction may also exist in patients with normal platelet counts. In this study, we performed analyses of platelet function and of von Willebrand factor in critically ill COVID-19 patients (n = 13). Platelet aggregometry was performed using ADP, collagen, epinephrin, and ristocetin. VWF and fibrinogen binding of platelets and CD62 and CD63 expression after thrombin stimulation were analyzed via flow cytometry. In addition, VWF antigen (VWF:Ag), collagen binding capacity (VWF:CB), and multimer analysis were performed next to routine coagulation parameters. All patients exhibited reduced platelet aggregati...
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