A systematic study and literature review of parental somatic mosaicism of FBN1 pathogenic variants in Marfan syndrome

2021 ◽  
pp. jmedgenet-2020-107604
Author(s):  
Paula Fernández-Álvarez ◽  
Marta Codina-Sola ◽  
Irene Valenzuela ◽  
Gisela Teixidó-Turá ◽  
Anna Cueto-González ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
De Novo ◽  
Normal Population ◽  
Genetic Disorders ◽  
Somatic Mosaicism ◽  
Clinical Signs ◽  
Systematic Analysis ◽  
Pathogenic Variants ◽  
Fibrillin 1 ◽  
Minor Criteria

BackgroundA proportion of de novo variants in patients affected by genetic disorders, particularly those with autosomal dominant (AD) inheritance, could be the consequence of somatic mosaicism in one of the progenitors. There is growing evidence that germline and somatic mosaicism are more common and play a greater role in genetic disorders than previously acknowledged. In Marfan syndrome (MFS), caused by pathogenic variants in the fibrillin-1 gene (FBN1) gene, approximately 25% of the disease-causing variants are reported as de novo. Only a few cases of parental mosaicism have been reported in MFS.MethodsEmploying an amplicon-based deep sequencing (ADS) method, we carried out a systematic analysis of 60 parents of 30 FBN1 positive, consecutive patients with MFS with an apparently de novo pathogenic variant.ResultsOut of the 60 parents studied (30 families), the majority (n=51, 85%) had a systemic score of 0, seven had a score of 1 and two a score of 2, all due to minor criteria common in the normal population. We detected two families with somatic mosaicism in one of the progenitors, with a rate of 6.6% (2/30) of apparently de novo cases.ConclusionsThe search for parental somatic mosaicism should be routinely implemented in de novo cases of MFS, to offer appropriate genetic and reproductive counselling as well as to reveal masked, isolated clinical signs of MFS in progenitors that may require specific follow-up.

scholarly journals Unsuspected somatic mosaicism for FBN1 gene contributes to Marfan syndrome

2021 ◽  
Author(s):  
Pauline Arnaud ◽  
Hélène Morel ◽  
Olivier Milleron ◽  
Laurent Gouya ◽  
Christine Francannet ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Somatic Mosaicism ◽  
Variant Calling ◽  
Copy Number Variations ◽  
Pathogenic Variant ◽  
Single Nucleotide Variants ◽  
Bioinformatics Analyses ◽  
Single Nucleotide ◽  
Fbn1 Gene ◽  
Pathogenic Variants

Abstract Purpose Individuals with mosaic pathogenic variants in the FBN1 gene are mainly described in the course of familial screening. In the literature, almost all these mosaic individuals are asymptomatic. In this study, we report the experience of our team on more than 5,000 Marfan syndrome (MFS) probands. Methods Next-generation sequencing (NGS) capture technology allowed us to identify five cases of MFS probands who harbored a mosaic pathogenic variant in the FBN1 gene. Results These five sporadic mosaic probands displayed classical features usually seen in Marfan syndrome. Combined with the results of the literature, these rare findings concerned both single-nucleotide variants and copy-number variations. Conclusion This underestimated finding should not be overlooked in the molecular diagnosis of MFS patients and warrants an adaptation of the parameters used in bioinformatics analyses. The five present cases of symptomatic MFS probands harboring a mosaic FBN1 pathogenic variant reinforce the fact that apparently asymptomatic mosaic parents should have a complete clinical examination and a regular cardiovascular follow-up. We advise that individuals with a typical MFS for whom no single-nucleotide pathogenic variant or exon deletion/duplication was identified should be tested by NGS capture panel with an adapted variant calling analysis.

scholarly journals A novel de novo DDX3X missense variant in a female with brachycephaly and intellectual disability: a case report

2021 ◽  
Vol 47 (1) ◽  
Author(s):  
Giada Moresco ◽  
Jole Costanza ◽  
Carlo Santaniello ◽  
Ornella Rondinone ◽  
Federico Grilli ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Clinical Presentation ◽  
De Novo ◽  
Clinical Signs ◽  
Missense Variant ◽  
Psychomotor Development ◽  
Helicase Domain ◽  
Protein Activity ◽  
Mrna Metabolism ◽  
Pathogenic Variants

Abstract Background De novo pathogenic variants in the DDX3X gene are reported to account for 1–3% of unexplained intellectual disability (ID) in females, leading to the rare disease known as DDX3X syndrome (MRXSSB, OMIM #300958). Besides ID, these patients manifest a variable clinical presentation, which includes neurological and behavioral defects, and abnormal brain MRIs. Case presentation We report a 10-year-old girl affected by delayed psychomotor development, delayed myelination, and polymicrogyria (PMG). We identified a novel de novo missense mutation in the DDX3X gene (c.625C > G) by whole exome sequencing (WES). The DDX3X gene encodes a DEAD-box ATP-dependent RNA-helicase broadly implicated in gene expression through regulation of mRNA metabolism. The identified mutation is located just upstream the helicase domain and is suggested to impair the protein activity, thus resulting in the altered translation of DDX3X-dependent mRNAs. The proband, presenting with the typical PMG phenotype related to the syndrome, does not show other clinical signs frequently reported in presence of missense DDX3X mutations that are associated with a most severe clinical presentation. In addition, she has brachycephaly, never described in female DDX3X patients, and macroglossia, that has never been associated with the syndrome. Conclusions This case expands the knowledge of DDX3X pathogenic variants and the associated DDX3X syndrome phenotypic spectrum.

Recurrent spontaneous coronary dissections in a patient with a de novo fibrillin-1 mutation without Marfan syndrome

2015 ◽  
Vol 113 (03) ◽  
pp. 668-670 ◽  
Author(s):  
Philipp von Hundelshausen ◽  
Konrad Oexle ◽  
Kiril Bidzhekov ◽  
Martin Schmitt ◽  
Michael Hristov ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
De Novo ◽  
Fibrillin 1

scholarly journals Cardiomyopathy in Genetic Aortic Diseases

2021 ◽  
Vol 9 ◽  
Author(s):  
Laura Muiño-Mosquera ◽  
Julie De Backer
Keyword(s):  
Marfan Syndrome ◽  
Myocardial Dysfunction ◽  
Genetic Defect ◽  
Positive Family History ◽  
Aortic Disease ◽  
Aortic Aneurysms ◽  
Aortic Diseases ◽  
Pathogenic Variants ◽  
Fibrillin 1

Genetic aortic diseases are a group of illnesses characterized by aortic aneurysms or dissection in the presence of an underlying genetic defect. They are part of the broader spectrum of heritable thoracic aortic disease, which also includes those cases of aortic aneurysm or dissection with a positive family history but in whom no genetic cause is identified. Aortic disease in these conditions is a major cause of mortality, justifying clinical and scientific emphasis on the aorta. Aortic valve disease and atrioventricular valve abnormalities are known as important additional manifestations that require careful follow-up and management. The archetype of genetic aortic disease is Marfan syndrome, caused by pathogenic variants in the Fibrillin-1 gene. Given the presence of fibrillin-1 microfibers in the myocardium, myocardial dysfunction and associated arrhythmia are conceivable and have been shown to contribute to morbidity and mortality in patients with Marfan syndrome. In this review, we will discuss data on myocardial disease from human studies as well as insights obtained from the study of mouse models of Marfan syndrome. We will elaborate on the various phenotypic presentations in childhood and in adults and on the topic of arrhythmia. We will also briefly discuss the limited data available on other genetic forms of aortic disease.

scholarly journals A large deletion in the COL2A1 gene expands the spectrum of pathogenic variants causing bulldog calf syndrome in cattle

2020 ◽  
Vol 62 (1) ◽  
Author(s):  
Joana Gonçalves Pontes Jacinto ◽  
Irene Monika Häfliger ◽  
Anna Letko ◽  
Cord Drögemüller ◽  
Jørgen Steen Agerholm
Keyword(s):  
De Novo ◽  
Genetic Disorders ◽  
Polymerase Chain Reaction Analysis ◽  
Large Deletion ◽  
Whole Genome Sequence ◽  
De Novo Mutation ◽  
Loss Of Function ◽  
Single Nucleotide Variants ◽  
Pathogenic Variants ◽  
Base Pair Deletion

Abstract Background Congenital bovine chondrodysplasia, also known as bulldog calf syndrome, is characterized by disproportionate growth of bones resulting in a shortened and compressed body, mainly due to reduced length of the spine and the long bones of the limbs. In addition, severe facial dysmorphisms including palatoschisis and shortening of the viscerocranium are present. Abnormalities in the gene collagen type II alpha 1 chain (COL2A1) have been associated with some cases of the bulldog calf syndrome. Until now, six pathogenic single-nucleotide variants have been found in COL2A1. Here we present a novel variant in COL2A1 of a Holstein calf and provide an overview of the phenotypic and allelic heterogeneity of the COL2A1-related bulldog calf syndrome in cattle. Case presentation The calf was aborted at gestation day 264 and showed generalized disproportionate dwarfism, with a shortened compressed body and limbs, and dysplasia of the viscerocranium; a phenotype resembling bulldog calf syndrome due to an abnormality in COL2A1. Whole-genome sequence (WGS) data was obtained and revealed a heterozygous 3513 base pair deletion encompassing 10 of the 54 coding exons of COL2A1. Polymerase chain reaction analysis and Sanger sequencing confirmed the breakpoints of the deletion and its absence in the genomes of both parents. Conclusions The pathological and genetic findings were consistent with a case of “bulldog calf syndrome”. The identified variant causing the syndrome was the result of a de novo mutation event that either occurred post-zygotically in the developing embryo or was inherited because of low-level mosaicism in one of the parents. The identified loss-of-function variant is pathogenic due to COL2A1 haploinsufficiency and represents the first structural variant causing bulldog calf syndrome in cattle. Furthermore, this case report highlights the utility of WGS-based precise diagnostics for understanding congenital disorders in cattle and the need for continued surveillance for genetic disorders in cattle.

scholarly journals Down syndrome with co-occurring Marfan syndrome

2020 ◽  
Vol 13 (9) ◽  
pp. e235988
Author(s):  
Miao Wei ◽  
Natasha Lepore ◽  
Kelli Paulsen ◽  
Jonathan D Santoro
Keyword(s):  
Down Syndrome ◽  
Medical Care ◽  
Marfan Syndrome ◽  
Trisomy 21 ◽  
Genetic Disorders ◽  
Close Monitoring ◽  
Genetic Syndromes ◽  
Organ Systems ◽  
Fibrillin 1 ◽  
Musculoskeletal Systems

Down syndrome (DS) and Marfan syndrome (MFS) are two unique genetic disorders that share limited phenotypic overlap. There are very few reported cases in the existing literature on overlapping DS and MFS. Although these two disorders are phenotypically unique, features present in these cases are variable, resulting in mixed and dominant expressions of particular features. We present the first adolescent case of trisomy 21 associated DS and fibrillin-1 gene associated MFS in the literature who had a height at 90th percentile for an 11-year old boy and discuss the implications of this case in terms of future medical care when these two genetic syndromes are present in the same individual. Understanding of certain features of the ‘non-dominating’ syndrome is crucial for clinicians to recognise when DS co-occurs with MFS. Close monitoring of the cardiovascular, ophthalmologic and musculoskeletal systems is recommended if both syndromes are diagnosed given that both can be independently associated with disorders in these organ systems.

scholarly journals Advantages of high throughput parallel sequencing in detecting somatic mosaicism in sporadic retinoblastoma

2020 ◽  
pp. 6-7
Author(s):  
Е.А. Алексеева ◽  
О.В. Бабенко ◽  
В.М. Козлова ◽  
Т.Л. Ушакова ◽  
Т.П. Казубская ◽  
...  
Keyword(s):  
Family History ◽  
High Throughput ◽  
De Novo ◽  
Somatic Mosaicism ◽  
Allelic Frequency ◽  
De Novo Mutations ◽  
Rb1 Gene ◽  
Parallel Sequencing ◽  
Pathogenic Variants

Почти 80% случаев наследственной ретинобластомы не имеют семейного анамнеза и возникают в результате мутаций de novo в гене RB1. Методом высокопроизводительного параллельного секвенирования (ВПС) проведено молекулярно-генетическое обследование 208 неродственных больных со спорадической РБ, среди которых 145 пациентов с унилатеральной формой заболевания и 63 - с билатеральной. В группе пациентов с билатеральной РБ молекулярные изменения в гене RB1 обнаружены в 90,5% (57/63) случаев. У 4,8% (3/63) пациентов определен мозаичный вариант мутации в гене RB1. В группе пациентов с унилатеральной РБ молекулярные изменения в гене RB1 выявлены в 17,9% (26/145) случаев. Среди исследованных пациентов соматический мозаицизм выявлен в 9,0% (13/165) случаев. Применение ВПС позволяет точно определять аллельную частоту вариантов, что делает поиск соматического мозаицизма эффективным. Almost 80% of cases of hereditary retinoblastoma do not have a family history and arise as a result of de novo mutations in the RB1 gene. An NGS test was performed on 208 unrelated patients with sporadic RB, including 145 patients with a unilateral form and 63 patients with a bilateral one. In the group of patients with bilateral RB, pathogenic variants in the RB1 gene were detected in 90.5% (57/63) cases. In 4.8% (3/63) of patients, a mosaic variants were determined. In the group of patients with unilateral RB, changes in the RB1 gene were detected in 17.9% (26/145) cases. Among the examined patients, somatic mosaicism was detected in 9.0% (13/165) cases. NGS allows us to determine the allelic frequency of variants, which makes the search for somatic mosaicism effective.

scholarly journals Expanding the phenotype associated to KMT2A variants: overlapping clinical signs between Wiedemann–Steiner and Rubinstein–Taybi syndromes

2020 ◽  
Vol 29 (1) ◽  
pp. 88-98
Author(s):  
Elisabetta Di Fede ◽  
Valentina Massa ◽  
Bartolomeo Augello ◽  
Gabriella Squeo ◽  
Emanuela Scarano ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
De Novo ◽  
Clinical Signs ◽  
Pathogenic Variants ◽  
Mutational Screening ◽  
Whole Exome ◽  
Epigenetic Machinery ◽  
Custom Made ◽  
Clinical Conditions ◽  
Generation Sequencing

AbstractLysine-specific methyltransferase 2A (KMT2A) is responsible for methylation of histone H3 (K4H3me) and contributes to chromatin remodeling, acting as “writer” of the epigenetic machinery. Mutations in KMT2A were first reported in Wiedemann–Steiner syndrome (WDSTS). More recently, KMT2A variants have been described in probands with a specific clinical diagnosis comprised in the so-called chromatinopathies. Such conditions, including WDSTS, are a group of overlapping disorders caused by mutations in genes coding for the epigenetic machinery. Among them, Rubinstein–Taybi syndrome (RSTS) is mainly caused by heterozygous pathogenic variants in CREBBP or EP300. In this work, we used next generation sequencing (either by custom-made panel or by whole exome) to identify alternative causative genes in individuals with a RSTS-like phenotype negative to CREBBP and EP300 mutational screening. In six patients we identified different novel unreported variants in KMT2A gene. The identified variants are de novo in at least four out of six tested individuals and all of them display some typical RSTS phenotypic features but also WDSTS specific signs. This study reinforces the concept that germline variants affecting the epigenetic machinery lead to a shared molecular effect (alteration of the chromatin state) determining superimposable clinical conditions.

scholarly journals Effects of fibrillin mutations on the behavior of heart muscle cells in Marfan syndrome

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jeffrey Aalders ◽  
Laurens Léger ◽  
Louis Van der Meeren ◽  
Natasja Van den Vreken ◽  
Andre G. Skirtach ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Myocardial Dysfunction ◽  
Electrode Array ◽  
Cyclic Strain ◽  
Culture Conditions ◽  
Pathogenic Variants ◽  
The Matrix ◽  
Heart Muscle Cells ◽  
Fibrillin 1 ◽  
Induced Pluripotent

Abstract Marfan syndrome (MFS) is a systemic disorder of connective tissue caused by pathogenic variants in the fibrillin-1 (FBN1) gene. Myocardial dysfunction has been demonstrated in MFS patients and mouse models, but little is known about the intrinsic effect on the cardiomyocytes (CMs). In this study, both induced pluripotent stem cells derived from a MFS-patient and the line with the corrected FBN1 mutation were differentiated to CMs. Several functional analyses are performed on this model to study MFS related cardiomyopathy. Atomic force microscopy revealed that MFS CMs are stiffer compared to corrected CMs. The contraction amplitude of MFS CMs is decreased compared to corrected CMs. Under normal culture conditions, MFS CMs show a lower beat-to-beat variability compared to corrected CMs using multi electrode array. Isoproterenol-induced stress or cyclic strain demonstrates lack of support from the matrix in MFS CMs. This study reports the first cardiac cell culture model for MFS, revealing abnormalities in the behavior of MFS CMs that are related to matrix defects. Based on these results, we postulate that impaired support from the extracellular environment plays a key role in the improper functioning of CMs in MFS.

scholarly journals Neonatal Marfan Syndrome

2019 ◽  
Vol 36 (S 02) ◽  
pp. S74-S76 ◽  
Author(s):  
Eleonora Tognato ◽  
Anna Perona ◽  
Angela Aronica ◽  
Antonella Bertola ◽  
Lina Cimminelli ◽  
...  
Keyword(s):  
Marfan Syndrome ◽  
Rare Condition ◽  
Ocular Involvement ◽  
Autosomal Dominant Disorder ◽  
Adequate Treatment ◽  
Pathogenic Variants ◽  
Fibrillin 1 ◽  
Birth Characteristics ◽  
Neonatal Marfan Syndrome ◽  
Male Neonate

Abstract Objective The Marfan syndrome (MFS) is an autosomal dominant disorder of connective tissue resulting from pathogenic variants of the fibrillin-1 gene (FBN1) with skeletal, cardiac, and ocular involvement. Study Design We report on a full-term male neonate, who showed at birth characteristics and dysmorphisms suggestive of nMFS, combined with the detection of severe cardiovascular disease. A multidisciplinary team made up of neonatologists and pediatricians, cardiologists, geneticists, ophtalmologists, physiatrists and physioterapists was formed to manage this patient. Results and Conclusion Early diagnosis of this rare condition is critical for adequate treatment and specific follow-up, and impacts significantly on prognosis.

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