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Moyamoya disease, a cerebrovascular disease leading to strokes in children and young adults, is characterized by progressive occlusion of the distal internal carotid arteries and the formation of collateral vessels. Altered genes play a prominent role in the etiology of moyamoya disease, but a causative gene is not identified in the majority of cases. Exome sequencing data from 151 individuals from 84 unsolved families were analyzed to identify further genes for moyamoya disease, then candidate genes assessed in additional cases (150 probands). Two families had the same rare variant in ANO1, which encodes a calcium-activated chloride channel, anoctamin-1. Haplotype analyses found the families were related, and ANO1 p.Met658Val segregated with moyamoya disease in the family with an LOD score of 3.3. Six additional ANO1 rare variants were identified in moyamoya disease families. The ANO1 rare variants were assessed using patch-clamp recordings, and the majority of variants, including ANO1 p.Met658Val, displayed increased sensitivity to intracellular Ca2+. Patients harboring these gain-of-function ANO1 variants had classic features of MMD, but also had aneurysm, stenosis, and/or occlusion in the posterior circulation. Our studies support that ANO1 gain-of-function pathogenic variants predispose to moyamoya disease and are associated with unique involvement of the posterior circulation.

Collagens are the most abundant proteins in the body and among the most biosynthetically complex. A molecular ensemble of over 20 endoplasmic reticulum resident proteins participates in collagen biosynthesis and contributes to heterogeneous post-translational modifications. Pathogenic variants in genes encoding collagens cause connective tissue disorders, including osteogenesis imperfecta, Ehlers-Danlos syndrome, and Gould syndrome (caused by mutations in COL4A1 and COL4A2), and pathogenic variants in genes encoding proteins required for collagen biosynthesis can cause similar but overlapping clinical phenotypes. Notably, pathogenic variants in lysyl hydroxylase 3 (LH3) cause a multisystem connective tissue disorder that exhibits pathophysiological features of collagen-related disorders. LH3 is a multifunctional collagen-modifying enzyme; however, its precise role(s) and substrate specificity during collagen biosynthesis has not been defined. To address this critical gap in knowledge, we generated LH3 KO cells and performed detailed quantitative and molecular analyses of collagen substrates. We found that LH3 deficiency severely impaired secretion of collagen α1α1α2(IV) but not collagens α1α1α2(I) or α1α1α1(III). Amino acid analysis revealed that LH3 is a selective LH for collagen α1α1α2(IV) but a general glucosyltransferase for collagens α1α1α2(IV), α1α1α2(I), and α1α1α1(III). Importantly, we identified rare variants that are predicted to be pathogenic in the gene encoding LH3 in two of 113 fetuses with intracranial hemorrhage-a cardinal feature of Gould syndrome. Collectively, our findings highlight a critical role of LH3 in α1α1α2(IV) biosynthesis and suggest that LH3 pathogenic variants might contribute to Gould syndrome.

BACKGROUND: Variants of COL4A1/COL4A2 genes have been reported in fetal intracranial hemorrhage (ICH) cases but their prevalence and characteristics have not been established in a large series of fetuses. Fetal neonatal alloimmune thrombocytopenia is a major acquired ICH factor but the prevalence and characteristics of inherited platelet disorder (IPD) gene variants leading to thrombocytopenia are unknown. Herein, we screened COL4A1/COL4A2 and IPD genes in a large series of ICH fetuses. METHODS: A cohort of 194 consecutive ICH fetuses were first screened for COL4A1/COL4A2 variants. We manually curated a list of 64 genes involved in IPD and investigated them in COL4A1/COL4A2 negative fetuses, using exome sequencing data from 101 of these fetuses. RESULT: Pathogenic variants of COL4A1/COL4A2 genes were identified in 36 fetuses (19%). They occurred de novo in 70% of the 32 fetuses for whom parental DNA was available. Pathogenic variants in two megakaryopoiesis genes (MPL and MECOM genes) were identified in two families with recurrent and severe fetal ICH, with variable extraneurological pathological features. CONCLUSION: Our study emphasizes the genetic heterogeneity of fetal ICH and the need to screen both COL4A1/COL4A2 and IPD genes in the etiological investigation of fetal ICH to allow proper genetic counseling.

Vascular aging affects multiple organ systems, Including the brain, where It can lead to vascular dementia. However, a concrete understanding of how aging specifically affects the brain vasculature, along with molecular readouts, remains vastly incomplete. Here, we demonstrate that aging is associated with a marked decline in Notch3 signaling in both murine and human brain vessels. To clarify the consequences of Notch3 loss in the brain vasculature, we used single-cell transcriptomics and found that Notch3 inactivation alters regulation of calcium and contractile function and promotes a notable increase in extracellular matrix. These alterations adversely impact vascular reactivity, manifesting as dilation, tortuosity, microaneurysms, and decreased cerebral blood flow, as observed by MRI. Combined, these vascular impairments hinder glymphatic flow and result in buildup of glycosaminoglycans within the brain parenchyma. Remarkably, this phenomenon mirrors a key pathological feature found in brains of patients with CADASIL, a hereditary vascular dementia associated with NOTCH3 missense mutations. Additionally, single-cell RNA sequencing of the neuronal compartment in aging Notch3- null mice unveiled patterns reminiscent of those observed in neurodegenerative diseases. These findings offer direct evidence that age-related NOTCH3 deficiencies trigger a progressive decline in vascular function, subsequently affecting glymphatic flow and culminating in neurodegeneration., Introduction Aging introduces a series of complex molecular, structural, and functional changes to blood vessels, with important consequences for organ physiology (1). In the brain, compromised vascular function can trigger [...]

BackgroundDespite many publications about cerebral cavernous malformations (CCMs), controversy remains regarding diagnostic and management strategies.ObjectiveTo develop guidelines for CCM management.MethodsThe Angioma Alliance ( www.angioma.org ), the patient support group in the United States advocating on behalf of patients and research in CCM, convened a multidisciplinary writing group comprising expert CCM clinicians to help summarize the existing literature related to the clinical care of CCM, focusing on 5 topics: (1) epidemiology and natural history, (2) genetic testing and counseling, (3) diagnostic criteria and radiology standards, (4) neurosurgical considerations, and (5) neurological considerations. The group reviewed literature, rated evidence, developed recommendations, and established consensus, controversies, and knowledge gaps according to a prespecified protocol.ResultsOf 1270 publications published between January 1, 1983 and September 31, 2014, we selected 98 based on methodological criteria, and identified 38 additional recent or relevant publications. Topic authors used these publications to summarize current knowledge and arrive at 23 consensus management recommendations, which we rated by class (size of effect) and level (estimate of certainty) according to the American Heart Association/American Stroke Association criteria. No recommendation was level A (because of the absence of randomized controlled trials), 11 (48%) were level B, and 12 (52%) were level C. Recommendations were class I in 8 (35%), class II in 10 (43%), and class III in 5 (22%).ConclusionCurrent evidence supports recommendations for the management of CCM, but their generally low levels and classes mandate further research to better inform clinical practice and update these recommendations. The complete recommendations document, including the criteria for selecting reference citations, a more detailed justification of the respective recommendations, and a summary of controversies and knowledge gaps, was similarly peer reviewed and is available on line www.angioma.org/CCMGuidelines .

Introduction Circulation of blood throughout the cardiovascular system results in biomechanical forces that profoundly influence vessel development and maintenance. Fluid shear stress along the inner lining of blood vessels imparts [...]

Background Early-onset isolated systemic hypertension is a rare condition of unknown genetic origin. Renovascular, renal parenchymal diseases or aortic coarctation are the most common causes of secondary systemic hypertension in younger children and neonates. We investigated the genetic bases of early-onset isolated systemic hypertension. Methods Whole-exome sequencing (WES) was followed by variant filtering and Sanger sequencing for validation and familial segregation of selected variants in a large consanguineous family. mRNA expression was performed to evaluate the impact of the predicted pathogenic variant on gene expression. WES or Sanger sequencing was performed in additional unrelated affected individuals. Results In one consanguineous family with four children presenting with isolated neonatal-onset systemic hypertension, we identified homozygous stop-gain variant in the NPR1 gene (NM_000906.4:c.1159C>T (p.Arg387Ter)) in the affected individuals. This variant leads to a dramatic reduction of NPR1 RNA levels. NPR1 gene analysis of additional families allowed the identification of another family with two affected children carrying homozygous frameshift variant in NPR1 (NM_000906.4:c.175del (p.Val59TrpfsTer8)). Conclusion We show for the first time that biallelic loss of function of NPR1 is responsible for isolated neonatal-onset systemic hypertension in humans, which represents a new autosomal recessive genetic cause of infantile systemic hypertension or cardiogenic shock. This is consistent with studies reporting early-onset systemic hypertension and sudden death in Npr1-deficient mice. NPR1 gene analysis should be therefore investigated in infants with early-onset systemic hypertension with or without cardiogenic shock of unknown origin. [ABSTRACT FROM AUTHOR]