Parkinson's disease, the most common age-related movement disorder, is a progressive neurodegenerative disease with unclear etiology. Key neuropathological hallmarks are Lewy bodies and Lewy ...neurites: neuronal inclusions immunopositive for the protein α-synuclein. In-depth ultrastructural analysis of Lewy pathology is crucial to understanding pathogenesis of this disease. Using correlative light and electron microscopy and tomography on postmortem human brain tissue from Parkinson's disease brain donors, we identified α-synuclein immunopositive Lewy pathology and show a crowded environment of membranes therein, including vesicular structures and dysmorphic organelles. Filaments interspersed between the membranes and organelles were identifiable in many but not all α-synuclein inclusions. Crowding of organellar components was confirmed by stimulated emission depletion (STED)-based super-resolution microscopy, and high lipid content within α-synuclein immunopositive inclusions was corroborated by confocal imaging, Fourier-transform coherent anti-Stokes Raman scattering infrared imaging and lipidomics. Applying such correlative high-resolution imaging and biophysical approaches, we discovered an aggregated protein-lipid compartmentalization not previously described in the Parkinsons' disease brain.
Thoracic aortic dilatation requires accurate and timely detection to prevent progression to thoracic aortic aneurysm and aortic dissection. The detection of thoracic aortic dilatation necessitates ...the availability of cut-off values for normal aortic diameters. Tools to evaluate aortic dimension above the root are scarce and inconsistent regarding age groups. The aim of this study was to provide reference values for aortic root and ascending aortic diameters on the basis of transthoracic echocardiographic measurements in a large cohort of children and adults. Diameters at the level of the sinuses of Valsalva (SoV) and ascending aorta (AA) were assessed with transthoracic echocardiography in 849 subjects (453 females, age range 1 to 85 years, mean 40.1 ± 21.3 years) and measured according to published guidelines. Linear regression analysis was applied to create nomograms, as well as equations for upper limits of normal and z-scores. SoV and AA diameters were strongly correlated with age, body surface area (BSA), and weight (r = 0.67 to 0.79, p <0.001 for all). Male subjects had significantly larger aortic dimensions at all levels in adulthood, even after BSA correction (p ≤0.004 for all age intervals). Gender-, age-, and BSA-specific upper limits of normal and z-score equations were developed from a multivariate regression model, which strongly predicts SoV and AA diameters (adjusted R2 for SoV = 0.84 and 0.67 and for AA = 0.82 and 0.74, for male and female subjects, respectively). In conclusion, this study provides widely applicable reference values for thoracic aortic dilatation screening purposes. Age, BSA, and gender must be taken into account when assessing an individual patient.
The diagnosis of Marfan syndrome (MFS) relies on defined clinical criteria (Ghent nosology), outlined by international expert opinion to facilitate accurate recognition of this genetic aneurysm ...syndrome and to improve patient management and counselling. These Ghent criteria, comprising a set of major and minor manifestations in different body systems, have proven to work well since with improving molecular techniques, confirmation of the diagnosis is possible in over 95% of patients. However, concerns with the current nosology are that some of the diagnostic criteria have not been sufficiently validated, are not applicable in children or necessitate expensive and specialised investigations. The recognition of variable clinical expression and the recently extended differential diagnosis further confound accurate diagnostic decision making. Moreover, the diagnosis of MFS--whether or not established correctly--can be stigmatising, hamper career aspirations, restrict life insurance opportunities, and cause psychosocial burden. An international expert panel has established a revised Ghent nosology, which puts more weight on the cardiovascular manifestations and in which aortic root aneurysm and ectopia lentis are the cardinal clinical features. In the absence of any family history, the presence of these two manifestations is sufficient for the unequivocal diagnosis of MFS. In absence of either of these two, the presence of a bonafide FBN1 mutation or a combination of systemic manifestations is required. For the latter a new scoring system has been designed. In this revised nosology, FBN1 testing, although not mandatory, has greater weight in the diagnostic assessment. Special considerations are given to the diagnosis of MFS in children and alternative diagnoses in adults. We anticipate that these new guidelines may delay a definitive diagnosis of MFS but will decrease the risk of premature or misdiagnosis and facilitate worldwide discussion of risk and follow-up/management guidelines.
Osteogenesis imperfecta Marini, Joan C; Forlino, Antonella; Bächinger, Hans Peter ...
Nature reviews. Disease primers,
08/2017, Letnik:
3
Journal Article
Recenzirano
Odprti dostop
Skeletal deformity and bone fragility are the hallmarks of the brittle bone dysplasia osteogenesis imperfecta. The diagnosis of osteogenesis imperfecta usually depends on family history and clinical ...presentation characterized by a fracture (or fractures) during the prenatal period, at birth or in early childhood; genetic tests can confirm diagnosis. Osteogenesis imperfecta is caused by dominant autosomal mutations in the type I collagen coding genes (COL1A1 and COL1A2) in about 85% of individuals, affecting collagen quantity or structure. In the past decade, (mostly) recessive, dominant and X-linked defects in a wide variety of genes encoding proteins involved in type I collagen synthesis, processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells have been shown to cause osteogenesis imperfecta. The large number of causative genes has complicated the classic classification of the disease, and although a new genetic classification system is widely used, it is still debated. Phenotypic manifestations in many organs, in addition to bone, are reported, such as abnormalities in the cardiovascular and pulmonary systems, skin fragility, muscle weakness, hearing loss and dentinogenesis imperfecta. Management involves surgical and medical treatment of skeletal abnormalities, and treatment of other complications. More innovative approaches based on gene and cell therapy, and signalling pathway alterations, are under investigation.
Objective Congenital hypogonadotropic hypogonadism (CHH) and constitutional delay of growth and puberty (CDGP) represent rare and common forms of GnRH deficiency, respectively. Both CDGP and CHH ...present with delayed puberty, and the distinction between these two entities during early adolescence is challenging. More than 30 genes have been implicated in CHH, while the genetic basis of CDGP is poorly understood. Design We characterized and compared the genetic architectures of CHH and CDGP, to test the hypothesis of a shared genetic basis between these disorders. Methods Exome sequencing data were used to identify rare variants in known genes in CHH (n = 116), CDGP (n = 72) and control cohorts (n = 36 874 ExAC and n = 405 CoLaus). Results Mutations in at least one CHH gene were found in 51% of CHH probands, which is significantly higher than in CDGP (7%, P = 7.6 × 10−11) or controls (18%, P = 5.5 × 10−12). Similarly, oligogenicity (defined as mutations in more than one gene) was common in CHH patients (15%) relative to CDGP (1.4%, P = 0.002) and controls (2%, P = 6.4 × 10−7). Conclusions Our data suggest that CDGP and CHH have distinct genetic profiles, and this finding may facilitate the differential diagnosis in patients presenting with delayed puberty.
Abstract Objectives Many non-musculoskeletal complaints in EDS-HT may be related to dysautonomia. This study therefore aims to investigate whether dysautonomia is present and to explore the ...underlying mechanisms. Methods A total of 39 females with EDS-HT and 35 age-matched controls underwent autonomic function testing. Resting autonomic tone was assessed using heart rate variability (frequency domain) and baroreflex sensitivity analysis (cross correlation). Autonomic reactivity was assessed using the Autonomic Reflex Screen test battery. Factors suspected to contribute to dysautonomia, e.g., neuropathy, medication use, decreased physical activity, depression, pain-induced sympathetic arousal, and connective tissue laxity, were quantified using validated questionnaires, the Beighton score, and measurement of skin extensibility. Results The EDS-HT group showed autonomic deregulation with increased sympathetic activity at rest and reduced sympathetic reactivity to stimuli. Increased resting activity was indicated by a higher LF/HF ratio compared to controls (1.7 ± 1.23 vs 0.9 ± 0.75, p = 0.002); decreased reactivity by a greater BP fall during valsalva (−19 ± 12 vs −8 ± 10, p < 0.001), and a smaller initial diastolic BP increase during tilt (7% vs 14%, p = 0.032). Orthostatic intolerance was significantly more prevalent in EDS-HT than controls (74% vs 34%) and was most frequently expressed as postural orthostatic tachycardia. Lowered QSART responses suggest that sympathetic neurogenic dysfunction is common in patients ( p < 0.013), which may explain the dysautonomia in EDS-HT. Further, connective tissue laxity and vasoactive medication use were identified as important factors in aggravating dysautonomia ( p < 0.035). Conclusion Dysautonomia consisting of cardiovascular and sudomotor dysfunction is present in EDS-HT. Neuropathy, connective tissue laxity, and vasoactive medication probably play a role in its development.
Aggressive arterial aneurysms, such as thoracic aortic aneurysms and aortic dissection, were found to be caused by mutations in the genes encoding the transforming growth factor β (TGF-β) receptor I ...or II, which are characteristic of the Loeys–Dietz syndrome. Screening for these mutations in persons at risk may allow preventive measures to be taken.
Aggressive arterial aneurysms were found to be caused by mutations in the genes encoding the transforming growth factor β receptor I or II. Screening for these mutations in persons at risk may allow preventive measures to be taken.
Mutations in the genes encoding transforming growth factor β (TGF-β) receptors 1 and 2 (
TGFBR1
and
TGFBR2,
respectively) have recently been found in association with a continuum of clinical features. On the mild end, the mutations have been found in association with a presentation similar to that of Marfan's syndrome or with familial thoracic aortic aneurysm and dissection,
1
,
2
and on the severe end, they are associated with a complex phenotype in which aortic dissection or rupture commonly occurs in childhood.
3
This complex phenotype is characterized by the triad of widely spaced eyes (hypertelorism); a bifid uvula, cleft palate, . . .
Proteoglycans are important components of cell plasma membranes and extracellular matrices of connective tissues. They consist of glycosaminoglycan chains attached to a core protein via a ...tetrasaccharide linkage, whereby the addition of the third residue is catalyzed by galactosyltransferase II (β3GalT6), encoded by B3GALT6. Homozygosity mapping and candidate gene sequence analysis in three independent families, presenting a severe autosomal-recessive connective tissue disorder characterized by skin fragility, delayed wound healing, joint hyperlaxity and contractures, muscle hypotonia, intellectual disability, and a spondyloepimetaphyseal dysplasia with bone fragility and severe kyphoscoliosis, identified biallelic B3GALT6 mutations, including homozygous missense mutations in family 1 (c.619G>C p.Asp207His) and family 3 (c.649G>A p.Gly217Ser) and compound heterozygous mutations in family 2 (c.323_344del p.Ala108Glyfs∗163, c.619G>C p.Asp207His). The phenotype overlaps with several recessive Ehlers-Danlos variants and spondyloepimetaphyseal dysplasia with joint hyperlaxity. Affected individuals’ fibroblasts exhibited a large decrease in ability to prime glycosaminoglycan synthesis together with impaired glycanation of the small chondroitin/dermatan sulfate proteoglycan decorin, confirming β3GalT6 loss of function. Dermal electron microcopy disclosed abnormalities in collagen fibril organization, in line with the important regulatory role of decorin in this process. A strong reduction in heparan sulfate level was also observed, indicating that β3GalT6 deficiency alters synthesis of both main types of glycosaminoglycans. In vitro wound healing assay revealed a significant delay in fibroblasts from two index individuals, pointing to a role for glycosaminoglycan defect in impaired wound repair in vivo. Our study emphasizes a crucial role for β3GalT6 in multiple major developmental and pathophysiological processes.
The Ehlers-Danlos syndrome Malfait, Fransiska; De Paepe, Anne
Advances in experimental medicine and biology,
01/2014, Letnik:
802
Journal Article, Book Chapter
Recenzirano
Odprti dostop
The Ehlers-Danlos Syndromes comprise a heterogeneous group of diseases, which are characterized by fragility of the soft connective tissues and widespread manifestations in skin, ligaments and ...joints, blood vessels and internal organs. The clinical spectrum varies from mild skin and joint hyperlaxity to severe physical disability and life-threatening vascular complications. The current Villefranche classification recognizes six subtypes, most of which are linked to mutations in one of the genes encoding fibrillar collagen proteins or enzymes involved in post-translational modification of these proteins. Establishing the correct EDS subtype has important implications for genetic counselling and management and is supported by specific biochemical and molecular investigations. Over the last years, the characterisation of several new EDS variants has broadened insights into the molecular pathogenesis of EDS by implicating genetic defects in the biosynthesis of other extracellular matrix molecules, such as proteoglycans and tenascin-X, or genetic defects in molecules involved in intracellular trafficking, secretion and assembly of extracellular matrix proteins.
We report heterozygous mutations in the genes encoding either type I or type II transforming growth factor β receptor in ten families with a newly described human phenotype that includes widespread ...perturbations in cardiovascular, craniofacial, neurocognitive and skeletal development. Despite evidence that receptors derived from selected mutated alleles cannot support TGFβ signal propagation, cells derived from individuals heterozygous with respect to these mutations did not show altered kinetics of the acute phase response to administered ligand. Furthermore, tissues derived from affected individuals showed increased expression of both collagen and connective tissue growth factor, as well as nuclear enrichment of phosphorylated Smad2, indicative of increased TGFβ signaling. These data definitively implicate perturbation of TGFβ signaling in many common human phenotypes, including craniosynostosis, cleft palate, arterial aneurysms, congenital heart disease and mental retardation, and suggest that comprehensive mechanistic insight will require consideration of both primary and compensatory events.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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