scholarly journals Quantifying the Genetic Basis of Marfan Syndrome Clinical Variability

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 574
Author(s):  
Thomas Grange ◽  
Mélodie Aubart ◽  
Maud Langeois ◽  
Louise Benarroch ◽  
Pauline Arnaud ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Clinical Features ◽  
Familial Aggregation ◽  
Phenotypic Variability ◽  
Connective Tissue Disorder ◽  
Clinical Feature ◽  
Phenotypic Variance ◽  
Genetic Modifiers ◽  
Clinical Variability ◽  
New Strategy

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with considerable inter- and intra-familial clinical variability. The contribution of inherited modifiers to variability has not been quantified. We analyzed the distribution of 23 clinical features in 1306 well-phenotyped MFS patients carrying FBN1 mutations. We found strong correlations between features within the same system (i.e., ophthalmology vs. skeletal vs. cardiovascular) suggesting common underlying determinants, while features belonging to different systems were largely uncorrelated. We adapted a classical quantitative genetics model to estimate the heritability of each clinical feature from phenotypic correlations between relatives. Most clinical features showed strong familial aggregation and high heritability. We found a significant contribution by the major locus on the phenotypic variance only for ectopia lentis using a new strategy. Finally, we found evidence for the “Carter effect” in the MFS cardiovascular phenotype, which supports a polygenic model for MFS cardiovascular variability and indicates additional risk for children of MFS mothers with an aortic event. Our results demonstrate that an important part of the phenotypic variability in MFS is under the control of inherited modifiers, widely shared between features within the same system, but not among different systems. Further research must be performed to identify genetic modifiers of MFS severity.

scholarly journals Reference Expression Profile of Three FBN1 Transcript Isoforms and Their Association with Clinical Variability in Marfan Syndrome

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 128
Author(s):  
Louise Benarroch ◽  
Mélodie Aubart ◽  
Marie-Sylvie Gross ◽  
Pauline Arnaud ◽  
Nadine Hanna ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Age Of Onset ◽  
Expression Profiles ◽  
Phenotypic Variability ◽  
Surrogate Endpoint ◽  
Connective Tissue Disorder ◽  
Clinical Variability ◽  
Fbn1 Gene ◽  
Adventitial Fibroblasts ◽  
Alternatively Spliced

Marfan syndrome (MFS) is a rare connective tissue disorder mainly due to mutations in the FBN1 gene. Great phenotypic variability is notable for age of onset, the presence and absence, and the number and the severity of the symptoms. Our team showed that FBN1 gene expression level was a good surrogate endpoint for severity of some MFS clinical features. Eight alternative transcripts are referenced for the FBN1 gene. We hypothesized that MFS clinical variability could be related to specific FBN1 isoforms. Isoform expression profiles were investigated in skin and adventitial fibroblasts from controls and MFS patients. The results of the study showed that, in skin and adventitial fibroblasts, only three isoforms were found: FBN1_001, FBN1_004, and FBN1_009. The main isoform was FBN1_001 and it was significantly reduced in skin and adventitial fibroblasts of MFS patients. The expressions of FBN1_004 and FBN1_009 isoforms were similar between controls and MFS patients. However, the expression of the three isoforms was correlated only in patients. Furthermore, their expression levels were associated with the presence of ectopia lentis in MFS patients. Therefore, our results highlight that the two minor alternatively spliced FBN1 isoforms play a possible role in the pathogenesis of the disease.

scholarly journals Clinical relevance of genotype–phenotype correlations beyond vascular events in a cohort study of 1500 Marfan syndrome patients with FBN1 pathogenic variants

2021 ◽  
Author(s):  
Pauline Arnaud ◽  
Olivier Milleron ◽  
Nadine Hanna ◽  
Jacques Ropers ◽  
Nadia Ould Ouali ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Phenotypic Variability ◽  
Premature Termination Codon ◽  
Connective Tissue Disorder ◽  
Vascular Events ◽  
Severe Scoliosis ◽  
Pathogenic Variants ◽  
Fibrillin 1 ◽  
Cysteine Content

Abstract Purpose Marfan syndrome (MFS) is a connective tissue disorder in which several systems are affected with great phenotypic variability. Although known to be associated with pathogenic variants in the FBN1 gene, few genotype–phenotype correlations have been found in proband studies only. Methods In 1,575 consecutive MFS probands and relatives from the most comprehensive database worldwide, we established survival curves and sought genotype–phenotype correlations. Results A risk chart could be established with clinical and genetic data. Premature termination codon variants were not only associated with a shorter life expectancy and a high lifelong risk of aortic event, but also with the highest risk of severe scoliosis and a lower risk for ectopia lentis (EL) surgery. In-frame variants could be subdivided according to their impact on the cysteine content of fibrillin-1 with a global higher severity for cysteine loss variants and the highest frequency of EL surgery for cysteine addition variants. Conclusion This study shows that FBN1 genotype–phenotype correlations exist for both aortic and extra-aortic features. It can be used for optimal risk stratification of patients with a great importance for genetic counseling and personalized medicine. This also provides additional data for the overall understanding of the role of fibrillin-1 in various organs.

scholarly journals Native α-Synuclein, 3-Nitrotyrosine Proteins, and Patterns of Nitro-α-Synuclein-Immunoreactive Inclusions in Saliva and Submandibulary Gland in Parkinson’s Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 715
Author(s):  
Emilio Fernández-Espejo ◽  
Fernando Rodríguez de Fonseca ◽  
Juan Suárez ◽  
Eduardo Tolosa ◽  
Dolores Vilas ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Nervous System ◽  
Clinical Features ◽  
Clinical Feature ◽  
Similar Concentration ◽  
Duct Cells ◽  
Nitrative Stress ◽  
Salivary Concentration

Background. Salivary α-synuclein (aSyn) and its nitrated form, or 3-nitrotyrosine-α-synuclein (3-NT-αSyn), hold promise as biomarkers for idiopathic Parkinson’s disease (IPD). Nitrative stress that is characterized by an excess of 3-nitrotyrosine proteins (3-NT-proteins) has been proposed as a pathogenic mechanism in IPD. The objective is to study the pathological role of native αSyn, 3-NT-αSyn, and 3-NT-proteins in the saliva and submandibulary glands of patients with IPD. Methods. The salivary and serum αSyn and 3-NT-proteins concentration is evaluated with ELISA in patients and controls. Correlations of αSyn and 3-NT-proteins content with clinical features of the disease are examined. Immunohistochemical 3-NT-αSyn expression in submandibulary gland sections is analyzed. Results. (a) Salivary concentration and saliva/serum ratios of native αSyn and 3-NT-proteins are similar in patients and controls; (b) salivary αSyn and 3-NT-proteins do not correlate with any clinical feature; and (c) three patterns of 3-NT-αSyn-positive inclusions are observed on histological sections: rounded “Lewy-type” aggregates of 10–25 µm in diameter, coarse deposits with varied morphology, and spheroid inclusions or bodies of 3–5 µm in diameter. “Lewy-type” and coarse inclusions are observed in the interlobular connective tissue of the gland, and small-sized bodies are located within the cytoplasm of duct cells. “Lewy-type” inclusions are only observed in patients, and the remaining patterns of inclusions are observed in both the patients and controls. Conclusions. The patients’ saliva presents a similar concentration of native αSyn and 3-nitrotyrosine-proteins than that of the controls, and no correlations with clinical features are found. These findings preclude the utility of native αSyn in the saliva as a biomarker, and they indicate the absence of nitrative stress in the saliva and serum of patients. As regards nitrated αSyn, “Lewy-type” inclusions expressing 3-NT-αSyn are observed in the patients, not the controls—a novel finding that suggests that a biopsy of the submandibulary gland, if proven safe, could be a useful technique for diagnosing IPD. Finally, to our knowledge, this is also the first description of 3-NT-αSyn-immunoreactive intracytoplasmic bodies in cells that are located outside the nervous system. These intracytoplasmic bodies are present in duct cells of submandibulary gland sections from all subjects regardless of their pathology, and they can represent an aging or involutional change. Further immunostaining studies with different antibodies and larger samples are needed to validate the data.

scholarly journals Cortical Excitability across the ALS Clinical Motor Phenotypes

2021 ◽  
Vol 11 (6) ◽  
pp. 715
Author(s):  
Thanuja Dharmadasa
Keyword(s):  
Motor Cortex ◽  
Cortical Excitability ◽  
Phenotypic Variability ◽  
Specific Treatment ◽  
Underlying Disease ◽  
Selective Vulnerability ◽  
Clinical Feature ◽  
Cortical Hyperexcitability ◽  
Wide Range

Amyotrophic lateral sclerosis (ALS) is characterized by its marked clinical heterogeneity. Although the coexistence of upper and lower motor neuron signs is a common clinical feature for most patients, there is a wide range of atypical motor presentations and clinical trajectories, implying a heterogeneity of underlying pathogenic mechanisms. Corticomotoneuronal dysfunction is increasingly postulated as the harbinger of clinical disease, and neurophysiological exploration of the motor cortex in vivo using transcranial magnetic stimulation (TMS) has suggested that motor cortical hyperexcitability may be a critical pathogenic factor linked to clinical features and survival. Region-specific selective vulnerability at the level of the motor cortex may drive the observed differences of clinical presentation across the ALS motor phenotypes, and thus, further understanding of phenotypic variability in relation to cortical dysfunction may serve as an important guide to underlying disease mechanisms. This review article analyses the cortical excitability profiles across the clinical motor phenotypes, as assessed using TMS, and explores this relationship to clinical patterns and survival. This understanding will remain essential to unravelling central disease pathophysiology and for the development of specific treatment targets across the ALS clinical motor phenotypes.

scholarly journals Parental mosaicism in Marfan and Ehlers–Danlos syndromes and related disorders

2021 ◽  
Author(s):  
Bertrand Chesneau ◽  
Aurélie Plancke ◽  
Guillaume Rolland ◽  
Nicolas Chassaing ◽  
Christine Coubes ◽  
...  
Keyword(s):  
High Resolution ◽  
Marfan Syndrome ◽  
High Resolution Melting ◽  
De Novo ◽  
Direct Sequencing ◽  
Causal Variant ◽  
Connective Tissue Disorder ◽  
High Resolution Melting Analysis ◽  
Aortic Diseases ◽  
Melting Analysis

AbstractMarfan syndrome (MFS) is a heritable connective tissue disorder (HCTD) caused by pathogenic variants in FBN1 that frequently occur de novo. Although individuals with somatogonadal mosaicisms have been reported with respect to MFS and other HCTD, the overall frequency of parental mosaicism in this pathology is unknown. In an attempt to estimate this frequency, we reviewed all the 333 patients with a disease-causing variant in FBN1. We then used direct sequencing, combined with High Resolution Melting Analysis, to detect mosaicism in their parents, complemented by NGS when a mosaicism was objectivized. We found that (1) the number of apparently de novo events is much higher than the classically admitted number (around 50% of patients and not 25% as expected for FBN1) and (2) around 5% of the FBN1 disease-causing variants were not actually de novo as anticipated, but inherited in a context of somatogonadal mosaicisms revealed in parents from three families. High Resolution Melting Analysis and NGS were more efficient at detecting and evaluating the level of mosaicism compared to direct Sanger sequencing. We also investigated individuals with a causal variant in another gene identified through our “aortic diseases genes” NGS panel and report, for the first time, on an individual with a somatogonadal mosaicism in COL5A1. Our study shows that parental mosaicism is not that rare in Marfan syndrome and should be investigated with appropriate methods given its implications in patient’s management.

scholarly journals Potential predictors of severe cardiovascular involvement in Marfan syndrome: the emphasized role of genotype–phenotype correlations in improving risk stratification—a literature review

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Roland Stengl ◽  
Bence Ágg ◽  
Miklós Pólos ◽  
Gábor Mátyás ◽  
Gábor Szabó ◽  
...  
Keyword(s):  
Risk Stratification ◽  
Marfan Syndrome ◽  
Current Knowledge ◽  
Imaging Techniques ◽  
Connective Tissue Disorder ◽  
Main Body ◽  
Wide Range ◽  
Stratification System ◽  
Genetically Determined ◽  
Aortic Dissections

Abstract Background Marfan syndrome (MFS) is a genetically determined systemic connective tissue disorder, caused by a mutation in the FBN1 gene. In MFS mainly the cardiovascular, musculoskeletal and ocular systems are affected. The most dangerous manifestation of MFS is aortic dissection, which needs to be prevented by a prophylactic aortic root replacement. Main body The indication criteria for the prophylactic procedure is currently based on aortic diameter, however aortic dissections below the threshold defined in the guidelines have been reported, highlighting the need for a more accurate risk stratification system to predict the occurrence of aortic complications. The aim of this review is to present the current knowledge on the possible predictors of severe cardiovascular manifestations in MFS patients, demonstrating the wide range of molecular and radiological differences between people with MFS and healthy individuals, and more importantly between MFS patients with and without advanced aortic manifestations. These differences originating from the underlying common molecular pathological processes can be assessed by laboratory (e.g. genetic testing) and imaging techniques to serve as biomarkers of severe aortic involvement. In this review we paid special attention to the rapidly expanding field of genotype–phenotype correlations for aortic features as by collecting and presenting the ever growing number of correlations, future perspectives for risk stratification can be outlined. Conclusions Data on promising biomarkers of severe aortic complications of MFS have been accumulating steadily. However, more unifying studies are required to further evaluate the applicability of the discussed predictors with the aim of improving the risk stratification and therefore the life expectancy and quality of life of MFS patients.

Abstract 3665: COL4A1 and COL4A2 Mutations cause Genetically Modifiable Cerebrovascular Diseases

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Marion Jeanne ◽  
Yi-Chinn Weng ◽  
Michelle de Leau ◽  
Cassandre Labelle-Dumais ◽  
Berkeley W Kauffman ◽  
...  
Keyword(s):  
Er Stress ◽  
Cell Biology ◽  
Phenotypic Variability ◽  
Cerebrovascular Diseases ◽  
Basement Membranes ◽  
Mutant Mice ◽  
Genetic Modifiers ◽  
Cellular Mechanisms ◽  
Cerebral Magnetic Resonance Imaging ◽  
Genetic Context

Mutations in the type IV collagen alpha 1 gene (COL4A1) cause Cerebrovascular Diseases (CVDs) in mice and human patients. Patients with COL4A1 mutations suffer from a broad range of CVDs, from infantile porencephaly to debilitating or fatal intracerebral hemorrhage (ICH), to subclinical cerebral microbleeds, suggesting that environmental and other genetic factors may influence their phenotypes. COL4A1 is one of the most abundant proteins in basement membranes and forms heterotrimers with COL4A2. Among possible pathogenic mechanisms are cellular stress due to the toxic intracellular aggregation of the COL4A1 and COL4A2 proteins and/or their absence in the basement membrane. Our first goal is to identify the relative contributions of COL4A1 and COL4A2 mutations to sporadic ICH and to understand the cellular mechanisms and genetic complexity underlying the disease. We identified novel COL4A1 mutations and for the first time, we discovered COL4A2 mutations in a cohort of 96 patients with sporadic ICH. Using a cell-based assay we determined that the mutations impair COL4A1 and COL4A2 secretion. We showed that mutant COL4A1 or COL4A2 proteins accumulate within the cell where they titrate normal COL4A1 and COL4A2 proteins. Interestingly, we found that some of the mutations can ultimately result in endoplasmic reticulum (ER) stress and activation of the Unfolded Protein Response. Our second goal was to test the hypothesis that differences in genetic context could contribute to phenotypic variability in human patients. Thus, we characterized CVD in Col4a1 mutant mice with two different genetic backgrounds. Using cerebral magnetic resonance imaging and histological analysis, we show that one or more genetic modifiers from the CAST/EiJ strain significantly reduce the size and frequency of ICHs detected in Col4a1 mutant mice on a C57BL/6J background. In conclusion, we found that both COL4A1 and COL4A2 mutations cause ICH in human patients, our results support that ER stress could be involved in the pathogenesis and we showed that genetic context is crucial for expressivity and severity of the CVD. We predict that ongoing experiments to better understand the cell biology of COL4A1 and COL4A2 mutations and the mechanisms of genetic modification could lead to targeted therapeutics to reduce the risk of CVD in patients with COL4A1 or COL4A2 mutations.

scholarly journals Optimising the mutation screening strategy in Marfan syndrome and identifying genotypes with more severe aortic involvement

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Roland Stengl ◽  
András Bors ◽  
Bence Ágg ◽  
Miklós Pólos ◽  
Gabor Matyas ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Single Gene ◽  
Mutation Screening ◽  
Screening Method ◽  
Connective Tissue Disorder ◽  
Screening Strategy ◽  
Gene Panel ◽  
Dominant Negative ◽  
Second Phase ◽  
High Detection Rate

Abstract Background Marfan syndrome (MFS) is a systemic connective tissue disorder with life-threatening manifestations affecting the ascending aorta. MFS is caused by dominant negative (DN) and haploinsufficient (HI) mutations of the FBN1 gene. Our aim was to identify mutations of MFS patients with high detection rate and to investigate the use of a gene panel for patients with Marfanoid habitus. We also aimed to examine correlations between genotype and cardiovascular manifestations to predict “malignant” mutations. Methods 136 individuals were enrolled. In the first phase, next-generation sequencing (NGS) and Sanger sequencing were performed for 57 patients to screen the FBN1 gene, followed by multiplex ligation-dependent probe amplification (MLPA) in negative cases. For repeated negative results, NGS gene panel involving 9 genes was used. In the second phase, 79 patients were tested primarily with the same gene panel, negative samples were tested by MLPA. Results 84 pathogenic mutations were detected, out of which 78 affected FBN1, 6 non-FBN1 mutations (2 TGFB2, 1 TGFBR2, 2 TGFBR1, 1 SMAD3) are associated with Loeys-Dietz syndrome (LDS). LDS patients had lower systemic score and they were younger, but their aortic involvement did not differ. MLPA detected 4 multi-exon deletions of FBN1 gene, which could not be identified by our first-step screening method. Aortic involvement (aortic dissection and/or dilation) did not differ significantly among HI and DN mutations (p = 0.061). Combined group of HI and DN mutations eliminating a disulphide-bonding cysteine (DN Cys) had significantly higher aortic involvement rate than DN mutations not eliminating a disulphide-bonding cysteine (DN non-Cys) (p < 0.001). Patients with DN Cys required significantly more aortic surgeries than HI and DN non-Cys mutations (p = 0.042 and p = 0.015, respectively). Conclusions Due to the relevant number of mutations affecting genes other than FBN1, preferred approach for testing individuals with Marfanoid habitus is using a gene panel rather than single-gene analysis, followed by MLPA for negative samples. DN Cys and HI mutations should be considered as risk factors for aortic involvement. Genetic testing for patients with Marfanoid features and a systemic score under 7 is recommended, as LDS patients may have lower scores, but they may have severe cardiovascular manifestations.

scholarly journals A Case Report of Marfan Syndrome with Literature Review

2015 ◽  
Vol 4 (4) ◽  
pp. 269
Author(s):  
Hemanth Kumar Kalla ◽  
Swarna Kumari ◽  
CH Rama rao ◽  
MKR Parthasarathy ◽  
S Surya prakash Reddy ◽  
...  
Keyword(s):  
Case Report ◽  
Connective Tissue ◽  
Marfan Syndrome ◽  
Clinical Signs ◽  
Connective Tissue Disorder ◽  
Multiple Organ ◽  
Review Of The Literature ◽  
Organ Systems ◽  
Loin Pain ◽  
Routine Physical Examination

Marfan syndrome(MFS) is a connective tissue disorder that affects multiple organ systems. Cardiovascular, ocular, and skeletal abnormalities are cardinal features of the syndrome. Its incidence is among the highest of any heritable disorder.Most patients who have Marfan syndrome are usually diagnosed incidentally when they present for a routine physical examination for various reasons. The purpose of this paper is to provide a review of the literature, as well as describe a 22-year-old male with MFS and right hydroureteronephrosis diagnosed incidentally when he attended our hospital for complaints of fever and right loin pain. This case report emphasizes importance of “Revised Ghent criteria” for the diagnosis of MFS and highlights various clinical signs of MFS<strong>.</strong>

scholarly journals Concurrent End-Stage Cardiomyopathy and Aortic Disease in Patients with Marfan Syndrome: A Case Report and Literature Review

2021 ◽  
Author(s):  
Timothy Smith ◽  
Jose Sleiman ◽  
Nikita Zadneulitca ◽  
Cedric Sheffield ◽  
Viviana Navas ◽  
...  
Keyword(s):  
Heart Failure ◽  
Case Report ◽  
Literature Review ◽  
Marfan Syndrome ◽  
Aortic Disease ◽  
Connective Tissue Disorder ◽  
Orthotopic Heart Transplantation ◽  
Bentall Procedure ◽  
Life Saving ◽  
End Stage

Abstract Background: Marfan syndrome (MFS) is a connective tissue disorder that can lead to aortic disease, arrhythmias and heart failure. Many centers are reluctant to offer orthotopic heart transplantation (OHT) for patients with MFS with concurrent aortic disease due to complexity of the surgery and perceived inferior results when compared to patients without MFS. Methods: We present a case of a patient with MFS with previous Bentall procedure who underwent successful OHT, accompanied by a literature review on OHT performed for patients with MFS. Results and Conclusions: Patients with MFS who underwent OHT had no difference in mortality compared to patients without MFS. Even though OHT is technically more challenging when combined with concurrent intervention for aortic disease, it should be considered as a life-saving operation for patients with MFS.

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