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 ◽  
...  

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.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3774-3774
Author(s):  
Luca Bernasconi ◽  
Roberto Herklotz ◽  
Martin Hergersberg ◽  
Andreas Huber

Abstract Background: a-thalassemia, the most prevalent of all thalassemias, is an inherited single gene disorder of the hemoglobin synthesis characterized by the absence or the reduced expression of a-globin genes resulting in an imbalanced ratio between a- and b-gobin chain synthesis. While some DNA alterations lead to microcytic anemia, the most others cause severe anemia and intrauterine death if co-inherited in a homozygous constellation. The most common genetic defects leading to the a-thalassemia phenotype are deletions of one or more of the two highly homologous a-globin genes. Less frequently, a-thalassemia derives from nondeletional mutations located in parts of the a-globin gene that are critical for its normal expression. So far the identification of the genetic background of a-thalassemic patients has included specific amplification of each a-globin gene followed by laborious and expensive mutation analysis methods such as denaturing gradient gel electrophoresis (DGGE), single-strand conformation polymorphism (SSCP) or direct sequencing of the entire a-genes. Method: We attempted to evaluate the performance of denaturing high performance liquid chromatography (dHPLC) technique to identify nondeletional mutations located in the a1- or a2-globin gene. Due to the high sequence homology of a1- and a2-globin genes, separate amplification of the two genes followed by nested PCR were performed. This generated four overlapping amplicons (a-dHPLC1 to 4) covering the whole a1/a2-globin locus including the 3′- and 5′-untranslated regions. The formation of DNA hetero-/homoduplexes was ensured by denaturing and slow reannealing of crude PCR products. Through a DNA separation column under partial-denaturing conditions, DNA homoduplexes were retained longer than their corresponding heteroduplexes generating distinguishable chromatographic profiles and hence allowing for the differentiation between wildtype and mutant DNA. Samples which differed from the wildtype in their elution profile were sequenced in both directions. Results: 50 patients showing a presumptive a-thalassemic hematological profile not due to deletional mutations (excluded by gap PCR technique) were tested. 10 carriers of a-thalassemia nondeletional alleles (previously identified by endonuclease restriction analysis) and 10 healthy patients were also included in the evaluation. Conclusion: Our results show that dHPLC is a reliable, sensitive, and specific screening method to detect pointmutations and small deletions located in the a-globin genes. Furthermore, the low costs of analysis and the rapidity of the screening (about 6 min/sample) make the dHPLC technique an appropriate alternative to technically demanding and time consuming mutation screening methods such as DGGE or SSCP analysis.


Biomolecules ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 128
Author(s):  
Keiichi Asano ◽  
Anna Cantalupo ◽  
Lauriane Sedes ◽  
Francesco Ramirez

About 20% of individuals afflicted with thoracic aortic disease have single-gene mutations that predispose the vessel to aneurysm formation and/or acute aortic dissection often without associated syndromic features. One widely studied exception is Marfan syndrome (MFS) in which mutations in the extracellular protein fibrillin-1 cause additional abnormalities in the heart, eyes, and skeleton. Mouse models of MFS have been instrumental in delineating major cellular and molecular determinants of thoracic aortic disease. In spite of research efforts, translating experimental findings from MFS mice into effective drug therapies for MFS patients remains an unfulfilled promise. Here, we describe a series of studies that have implicated endothelial dysfunction and improper angiotensin II and TGFβ signaling in driving thoracic aortic disease in MFS mice. We also discuss how these investigations have influenced the way we conceptualized possible new therapies to slow down or even halt aneurysm progression in this relatively common connective tissue disorder.


2020 ◽  
Vol 21 (2) ◽  
pp. 117-130 ◽  
Author(s):  
Mohammad J. Hosen ◽  
Mahmudul Hasan ◽  
Sourav Chakraborty ◽  
Ruhshan A. Abir ◽  
Abdullah Zubaer ◽  
...  

Objectives: The Arterial Tortuosity Syndrome (ATS) is an autosomal recessive connective tissue disorder, mainly characterized by tortuosity and stenosis of the arteries with a propensity towards aneurysm formation and dissection. It is caused by mutations in the SLC2A10 gene that encodes the facilitative glucose transporter GLUT10. The molecules transported by and interacting with GLUT10 have still not been unambiguously identified. Hence, the study attempts to identify both the substrate binding site of GLUT10 and the molecules interacting with this site. Methods: As High-resolution X-ray crystallographic structure of GLUT10 was not available, 3D homology model of GLUT10 in open conformation was constructed. Further, molecular docking and bioinformatics investigation were employed. Results and Discussion: Blind docking of nine reported potential in vitro substrates with this 3D homology model revealed that substrate binding site is possibly made with PRO531, GLU507, GLU437, TRP432, ALA506, LEU519, LEU505, LEU433, GLN525, GLN510, LYS372, LYS373, SER520, SER124, SER533, SER504, SER436 amino acid residues. Virtual screening of all metabolites from the Human Serum Metabolome Database and muscle metabolites from Human Metabolite Database (HMDB) against the GLUT10 revealed possible substrates and interacting molecules for GLUT10, which were found to be involved directly or partially in ATS progression or different arterial disorders. Reported mutation screening revealed that a highly emergent point mutation (c. 1309G>A, p. Glu437Lys) is located in the predicted substrate binding site region. Conclusion: Virtual screening expands the possibility to explore more compounds that can interact with GLUT10 and may aid in understanding the mechanisms leading to ATS.


Author(s):  
Bertrand Chesneau ◽  
Aurélie Plancke ◽  
Guillaume Rolland ◽  
Nicolas Chassaing ◽  
Christine Coubes ◽  
...  

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.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Roland Stengl ◽  
Bence Ágg ◽  
Miklós Pólos ◽  
Gábor Mátyás ◽  
Gábor Szabó ◽  
...  

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.


2013 ◽  
Vol 7 (12) ◽  
pp. 929-940 ◽  
Author(s):  
Amna Afzal ◽  
Yasra Sarwar ◽  
Aamir Ali ◽  
Abbas Maqbool ◽  
Muhammad Salman ◽  
...  

Introduction: This study aimed to determine the drug susceptibility patterns and genetic elements related to drug resistance in isolates of Salmonella enterica serovar Typhi (S. Typhi) from the Faisalabad region of Pakistan. Methodology: The drug resistance status of 80 isolates were evaluated by determining antimicrobial susceptibility, MICs, drug resistance genes involved, and the presence of integrons. Nalidixic acid resistance and reduced susceptibility to ciprofloxacin were also investigated by mutation screening of the gyrA, gyrB, parC, and parE genes. Results: Forty-seven (58.7%) isolates were multidrug resistant (MDR). Among the different resistance (R) types, the most commonly observed (13/80) was AmChStrTeSxtSmzTmp, which is the most frequent type observed in India and Pakistan. The most common drug resistant genes were blaTEM-1, cat, strA-strB, tetB, sul1, sul2, and dfrA7. Among the detected genes, only dfrA7 was found to be associated in the form of a single gene cassette within the class 1 integrons. Conclusions: MIC determination of currently used drugs revealed fourth-generation gatifloxacin as an effective drug against multidrug-resistant S. Typhi, but its clinical use is controversial. The Ser83→Phe substitution in gyrA was the predominant alteration in nalidixic acid-resistant isolates, exhibiting reduced susceptibility and increased MICs against ciprofloxacin. No mutations in gyrB, parC, or parE were detected in any isolate.


2015 ◽  
Vol 4 (4) ◽  
pp. 269
Author(s):  
Hemanth Kumar Kalla ◽  
Swarna Kumari ◽  
CH Rama rao ◽  
MKR Parthasarathy ◽  
S Surya prakash Reddy ◽  
...  

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>


Author(s):  
Timothy Smith ◽  
Jose Sleiman ◽  
Nikita Zadneulitca ◽  
Cedric Sheffield ◽  
Viviana Navas ◽  
...  

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.


2014 ◽  
Vol 4 (2) ◽  
pp. 111-114
Author(s):  
Sharmin Mahbuba ◽  
Fauzia Mohsin ◽  
Rubaiya Islam ◽  
Tahmina Begum

Marfan syndrome is an inherited connective tissue disorder that is transmitted as an autosomal dominant trait. These cases can be diagnosed by molecular cytogenetic techniques. A modified Ghent criteria using systemic scoring system can also identify these cases in absence of molecular cytogenetic techniques.We report a case of a 6 year 5 month old boy who presented with the complaints of excessive sweating sinceinfancy and protrusion of both eye balls which was non progressive since early childhood. On examination, some skeletal features of Marfan syndrome was found and echocardiogram showed huge dilatation of root of aorta which helped in diagnosis by scoring system.Birdem Med J 2014; 4(2): 111-114


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