21 research outputs found

    Elucidating the clinical and molecular spectrum of SMARCC2-associated NDD in a cohort of 65 affected individuals

    Get PDF
    Purpose: Coffin-Siris and Nicolaides-Baraitser syndromes are recognizable neurodevelopmental disorders caused by germline variants in BAF complex subunits. The SMARCC2 BAFopathy was recently reported. Herein, we present clinical and molecular data on a large cohort. Methods: Clinical symptoms for 41 novel and 24 previously published affected individuals were analyzed using the Human Phenotype Ontology. For genotype-phenotype correlations, molecular data were standardized and grouped into non-truncating and likely gene-disrupting (LGD) variants. Missense variant protein expression and BAF-subunit interactions were examined using 3D protein modeling, co-immunoprecipitation, and proximity-ligation assays. Results: Neurodevelopmental delay with intellectual disability, muscular hypotonia, and behavioral disorders were the major manifestations. Clinical hallmarks of BAFopathies were rare. Clinical presentation differed significantly, with LGD variants being predominantly inherited and associated with mildly reduced or normal cognitive development, whereas non-truncating variants were mostly de novo and presented with severe developmental delay. These distinct manifestations and non-truncating variant clustering in functional domains suggest different pathomechanisms. In vitro testing showed decreased protein expression for N-terminal missense variants similar to LGD. Conclusion: This study improved SMARCC2 variant classification and identified discernible SMARCC2-associated phenotypes for LGD and non-truncating variants, which were distinct from other BAFopathies. The pathomechanism of most non-truncating variants has yet to be investigated.</p

    Elucidating the clinical and molecular spectrum of SMARCC2-associated NDD in a cohort of 65 affected individuals

    Get PDF
    Purpose: Coffin-Siris and Nicolaides-Baraitser syndromes are recognizable neurodevelopmental disorders caused by germline variants in BAF complex subunits. The SMARCC2 BAFopathy was recently reported. Herein, we present clinical and molecular data on a large cohort. Methods: Clinical symptoms for 41 novel and 24 previously published affected individuals were analyzed using the Human Phenotype Ontology. For genotype-phenotype correlations, molecular data were standardized and grouped into non-truncating and likely gene-disrupting (LGD) variants. Missense variant protein expression and BAF-subunit interactions were examined using 3D protein modeling, co-immunoprecipitation, and proximity-ligation assays. Results: Neurodevelopmental delay with intellectual disability, muscular hypotonia, and behavioral disorders were the major manifestations. Clinical hallmarks of BAFopathies were rare. Clinical presentation differed significantly, with LGD variants being predominantly inherited and associated with mildly reduced or normal cognitive development, whereas non-truncating variants were mostly de novo and presented with severe developmental delay. These distinct manifestations and non-truncating variant clustering in functional domains suggest different pathomechanisms. In vitro testing showed decreased protein expression for N-terminal missense variants similar to LGD. Conclusion: This study improved SMARCC2 variant classification and identified discernible SMARCC2-associated phenotypes for LGD and non-truncating variants, which were distinct from other BAFopathies. The pathomechanism of most non-truncating variants has yet to be investigated.</p

    Redundant roles for sox7 and sox18 in arteriovenous specification in Zebrafish

    No full text
    The specification of arteries and veins is an essential process in establishing and maintaining a functional blood vessel system. Incorrect arteriovenous specification disrupts embryonic development but has also been diagnosed in human syndromes such as hypotrichosis-lymphedema-telangiectasia, characterized by defects in blood and lymphatic vessels and associated with mutations in SOX18. Here we characterize the role of sox7 and sox18 during zebrafish vasculogenesis. Sox7 and sox18 are specifically expressed in the developing vasculature, and simultaneous loss of their function results in a severe loss of the arterial identity of the presumptive aorta which instead expresses venous markers, followed by dramatic arteriovenous shunt formations. Our study identifies members of the Sox family as key factors in specifying arteriovenous identity and will help to better understand hypotrichosis- lymphedema-telangiectasia and other diseases

    Measurement of antibodies to avian influenza virus A(H7N7) in humans by hemagglutination inhibition test.

    No full text
    During the epizootic of highly pathogenic avian influenza A(H7N7) in 2003 in The Netherlands, RT-PCR and culture confirmed infection was detected in 89 persons who were ill. A modified hemagglutination inhibition (HI) test using horse erythrocytes and 2 hemagglutinating units of virus was applied to assess retrospectively the extent of human (subclinical) infection. Validation of the HI-test with sera from 34 RT-PCR and culture confirmed A(H7) infected persons and sera from 100 persons from a human influenza vaccine trial in autumn 2002 showed that this HI-test had a sensitivity of 85% and a specificity of 100% when using a cut-off titer of > or =10. Using this cut-off value, A(H7) specific antibodies were detected in 49% of 508 persons exposed to poultry and in 64% of 63 persons exposed to A(H7) infected persons. Correlation of seropositivity with the occurrence of eye symptoms in exposed persons who had not received antiviral prophylaxis and of reduced seropositivity with taking antiviral prophylaxis provided further evidence that the A(H7) HI antibody titers were real. In conclusion, by applying an HI-test using horse erythrocytes human antibodies against the avian A(H7N7) virus were detected with high sensitivity and specificity in an unexpectedly high proportion of exposed persons

    Loss of lung microvascular endothelial Piezo2 expression impairs NO synthesis, induces EndMT, and is associated with pulmonary hypertension

    No full text
    Mechanical forces are translated into biochemical stimuli by mechanotransduction channels, such as the mechanically activated cation channel Piezo2. Lung Piezo2 expression has recently been shown to be restricted to endothelial cells. Hence, we aimed to investigate the role of Piezo2 in regulation of pulmonary vascular function and structure, as well as its contribution to development of pulmonary arterial hypertension (PAH). The expression of Piezo2 was significantly reduced in pulmonary microvascular endothelial cells (MVECs) from patients with PAH, in lung tissue from mice with a Bmpr2+/R899X knock-in mutation commonly found in patients with pulmonary hypertension, and in lung tissue of monocrotaline (MCT) and sugen-hypoxia-induced PH (SuHx) PAH rat models, as well as from a swine model with pulmonary vein banding. In MVECs, Piezo2 expression was reduced in response to abnormal shear stress, hypoxia, and TGFβ stimulation. Functional studies in MVECs exposed to shear stress illustrated that siRNA-mediated Piezo2 knockdown impaired endothelial alignment, calcium influx, phosphorylation of AKT, and nitric oxide production. In addition, siPiezo2 reduced the expression of the endothelial marker PECAM-1 and increased the expression of vascular smooth muscle markers ACTA2, SM22a, and calponin. Thus, Piezo2 acts as a mechanotransduction channel in pulmonary MVECs, stimulating shear-induced production of nitric oxide and is essentially involved in preventing endothelial to mesenchymal transition. Its blunted expression in pulmonary hypertension could impair the vasodilator capacity and stimulate vascular remodeling, indicating that Piezo2 might be an interesting therapeutic target to attenuate progression of the disease.NEW & NOTEWORTHY The mechanosensory ion channel Piezo2 is exclusively expressed in lung microvascular endothelial cells (MVECs). Patient MVECs as well as animal models of pulmonary (arterial) hypertension showed lower expression of Piezo2 in the lung. Mechanistically, Piezo2 is required for calcium influx and NO production in response to shear stress, whereas stimuli known to induce endothelial to mesenchymal transition (EndMT) reduce Piezo2 expression in MVECs, and Piezo2 knockdown induces a gene and protein expression pattern consistent with EndMT
    corecore