The molecular genetics of Marfan syndrome and related disorders

Addressing Stunting in Children Under Five: Insights and Opportunities from Nepal, Bangladesh, and Vietnam-A Review of Literature

Background: Stunting remains a significant global health issue, particularly in low- and middle-income countries (LMICs). Globally, around 22% of children under five are affected, with high rates persisting in South and Southeast Asia. This review examines government-led programs in high-performing LMICs (Nepal, Bangladesh, and Vietnam) to identify key strategies and opportunities for effective intervention. Methods: A literature search was conducted on PubMed using keywords and Medical Subject Heading terms, including "stunting", "child undernutrition", "malnutrition" and the names of the three specified countries. Articles were evaluated for relevance based on their focus on stunting prevalence, risk factors, and interventions in these countries, without restrictions on publication date or language. Results: Stunting prevalence among children under five has significantly declined in Nepal, Bangladesh, and Vietnam over the past two decades, reflecting the impact of sustained nutrition and health interventions. Nepal reduced stunting from 55.8% in 2000 to 26.7% in 2022, Bangladesh from 54.7% to 26.4%, and Vietnam from 41.5% to 19.3%. Successful strategies included multisectoral approaches integrating nutrition-specific and nutrition-sensitive interventions, enhanced policy frameworks, and strong governance. Despite progress, challenges remain, such as high wasting prevalence in Nepal and disparities among marginalized communities in Vietnam, emphasizing the need for targeted, context-specific interventions. Conclusions: Effective stunting reduction requires multisectoral strategies addressing underlying, intermediate, and immediate determinants. Insights from Nepal, Bangladesh, and Vietnam highlight the importance of sustained government commitment, robust policies, and coordinated interventions. Adapting these successful strategies to local contexts can support stunting prevention and management, promoting healthier and more resilient communities.

Stabilisation of extracellular matrix is crucial to rapamycin-mediated life span increase in Marfan mgR/mgR mice

Marfan syndrome is a hereditary connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene (FBN1) and altered TGF-β signalling. Life-threatening complications involve thoracic aortic aneurysms (TAA) and dissections due to the disruption of microfibrillar assembly in the aortic wall. We previously demonstrated that Rapamycin, a typical mTOR pathway inhibitor, limits the ascending aorta elastolysis and expansion, significantly increasing lifespan in an established murine model of Marfan syndrome (Zaradzki et al., Biochem Pharmacol 2022). This study aimed to investigate how mTOR inhibition stabilises the aorta in fibrillin-1 hypomorphic mgR/mgR mice and previously observed increased life expectancy. We used antibody microarrays to detect protein expression in the proximal thoracic aorta of sham or rapamycin-treated male and female mgR/mgR mice immediately after the two-week treatment. Immunofluorescence staining was performed to visualize and quantify protein expression in the ascending thoracic aorta and arch four weeks after the short-term rapamycin treatment was completed. We showed that rapamycin significantly increased the abundance of extracellular matrix (ECM) proteins like cytokeratin-18 and betaglycan, also known as the TGF-β type 3 receptor (TGFBR3). In addition, it raises the abundance of aggrecanase-2 (ADAMTS5) and xylosyltransferase-1 proteins, enzymes involved in ECM remodelling and homeostasis. In conclusion, rapamycin affects the composition and organization of key ECM components, which determine the structure-function relationships in the aorta, thereby maintaining the balance critical for the increase in life expectancy. Using mTOR modulators for targeted therapy may help to prevent aortic complications of MFS and improve clinical outcomes.

Functional analysis of a novel FBN1 deep intronic variant causing Marfan syndrome in a Chinese patient

Marfan syndrome (MFS MIM#154700), due to pathogenic variants in the FBN1 gene, is an autosomal dominant connective tissue disorder, typically involving the skeletal, cardiovascular and ocular systems. Currently, over 3000 MFS patients were reported, and approximately 1800 pathogenic variants in FBN1 were identified. However, the molecular diagnosis still remains challenging for 8%-10% of patients with clinical features suggestive of MFS. In this study, we reported a 2-month-old Chinese female patient whose clinical features were compatible with the MFS. Whole-exome sequencing (WES) identified a novel de novo deep intronic variant, c.4943-8_4943-7insTATGTGATATTCAT TCAC in intron 40 of FBN1 that was predicted to affect the RNA splicing. Minigene analysis showed that this variant causes skipping of exon 41, leading to the deletion of 41 amino acids (c.4943_5065del, p.Val1649_Asp1689del). It confirmed the pathogenic nature of the variant and established the genotype-phenotype relationship. Our study expands the mutation spectrum of FBN1 and emphasizes the importance of deep intronic variant interpretation and the need for additional functional studies to verify the pathogenicity of these variants.

Measuring contractile forces in vascular smooth muscle cells

Vascular smooth muscle cell (VSMC) contractility mediates blood vessel tone. Abnormalities in VSMC function and in blood vessel tone can contribute to a variety of cardiovascular diseases. This review examines the role of VSMC contractile force in vascular disease, divided into two primary sections. The first section introducing VSMC mechanical contraction and detailing the molecular mechanisms of VSMC contractility in normal and pathological states. The second section exploring methods of measuring contraction in VSMCs, such as Ca2+ imaging, myography, and traction force microscopy, and highlighting where each method is of best use. Understanding the mechanical properties and contractile profiles of VSMCs offers valuable insights into disease mechanisms. By investigating these aspects, this review describes the potential of VSMC contractile forces as diagnostic markers and therapeutic targets in vascular disease.

A novel missense variant of FBN1 gene in a Sardinian family with Marfan syndrome: a case report

Background

Marfan Syndrome (MS) is a connective tissue disorder, an autosomal dominant condition mostly caused by variants in the FBN1 gene, which encodes for fibrillin-1 protein. Anomalies in the gene lead to a wide variety of clinical manifestations, including disorders of the cardiac, ocular and musculoskeletal system. We present a case of a child belonging to a Sardinian family of four generations, with a novel variant found in the FBN1 gene.

Objective

To include this novel missense FBN1 variant into genetic counselling for Marfan Syndrome and to discuss its genotypic-phenotypic correlation.

Methods

Firstly, the proband was diagnosed with Marfan Syndrome using 2020 Revised Ghent Criteria, and she then underwent genetic testing using Next Generation sequencing.

Results

The NGS revealed a novel heterozygous missense variant (c.2348A>G) in the FBN1 gene, in exon 20. This genetic variant caused a missense substitution of a serine residue with an arginine residue in the position 783 of Fibrillin-1 protein. The variant was then evaluated in the other family members, and was eventually only found in symptomatic individuals, regardless of the severity of their phenotype, demonstrating the segregation with MS; furthermore, it showed complete penetrance with the disease.

Conclusions

Our results suggest that this variant is responsible for MS and it therefore should be included in genetic diagnoses and counselling discussion.

Recent progress in oculopharyngodistal myopathy research from clinical and genetic viewpoints

Oculopharyngodistal myopathy (OPDM) is a rare muscular disorder characterized by ocular symptoms, pharyngeal symptoms, facial weakness, and distal predominant limb muscle weakness. The cause of the disease was unknown for a long time. Recently, however, it has been reported that expansions of CGG or CCG repeats in LRP12, LOC642361/NUTM2B-AS1, GIPC1, NOTCH2NLC, RILPL1, and ABCD3 are the causes of the disease. Cases sometimes present with neurological symptoms, and the clinical spectrum of diseases caused by expansions of CGG or CCG repeats has been proposed to be called FNOP-spectrum disorder after the names of fragile X-associated tremor/ataxia syndrome, neuronal intranuclear inclusion disease, oculopharyngeal myopathy with leukoencephalopathy, and OPDM. In this article, the recent progress in the field of OPDM is reviewed, and remaining issues in OPDM are discussed.

Thoracic endovascular aortic repair in connective tissue disease patients is not a definitive option

OBJECTIVE

Open surgery is the gold standard for patients a connective tissue disorder (CTD). Thoracic endovascular aortic repair (TEVAR) is used in emergencies and patient-specific situations. Limited data on durability of TEVAR in patients with CTD exist. The purpose of this study was to investigate the durability, complications, and outcomes of TEVAR in patients with CTD.

METHODS

This single-center retrospective study included 40 patients with CTD who underwent TEVAR for thoracoabdominal aortic aneurysm or aortic dissection from February 2014 to April 2021. CTDs included Marfan syndrome, Loey-Dietz syndrome, and nonspecific CTD-related diagnoses. Primary outcomes included aortic-related morbidities, time to and type of postoperative reinterventions, and time to open/hybrid conversion. Time to conversion and reintervention was calculated using Kaplan-Meier estimation. Predictors of reintervention and open/hybrid conversion were evaluated using Cox proportional hazards models.

RESULTS

The median age was 53 years with 52.5% of the patients being female. Marfan syndrome was diagnosed in 57.5%, Loey-Dietz syndrome in 2.5%, and 40% had a diagnosed nonspecific or other CTD. Thirty-two (80%) had prior aortic interventions. Thoracic aneurysm existed in 52.5% and dissection in 82.5%. The average maximum thoracic aortic diameter was 55.2 mm. There were two mortalities within the first month. Of the remaining 38 patients, 71.1% had aneurysm-related morbidities, including 81.5% with aneurysmal degeneration and 33.3% with endoleak. Overall, 62.5% required reintervention. Of those, median time to reintervention was 9.1 months, including redo-TEVAR/extension in 32%, ascending/arch repair in 24%, open thoracoabdominal aortic repair in 56%, and false lumen embolization in 16%. Open conversions and reintervention were most likely to occur within the first year, with freedom of open conversion of 67.2% at 1 year, and 59.7% at 2 and 3 years, and freedom of reintervention of 49.8%, 36.0%, and 30.0% at 1, 2, and 3 years, respectively.

CONCLUSIONS

This study suggests that TEVAR for patients with CTD can be performed safely; however, patients are at high risk for aortic-related morbidities and reintervention. Reinterventions and open conversion are common and more likely to occur within 1 year. TEVAR should remain limited in this population until more durable outcomes are possible.

Risk factors affecting polygenic score performance across diverse cohorts

Apart from ancestry, personal or environmental covariates may contribute to differences in polygenic score (PGS) performance. We analyzed the effects of covariate stratification and interaction on body mass index (BMI) PGS (PGSBMI) across four cohorts of European (N = 491,111) and African (N = 21,612) ancestry. Stratifying on binary covariates and quintiles for continuous covariates, 18/62 covariates had significant and replicable R2 differences among strata. Covariates with the largest differences included age, sex, blood lipids, physical activity, and alcohol consumption, with R2 being nearly double between best- and worst-performing quintiles for certain covariates. Twenty-eight covariates had significant PGSBMI-covariate interaction effects, modifying PGSBMI effects by nearly 20% per standard deviation change. We observed overlap between covariates that had significant R2 differences among strata and interaction effects - across all covariates, their main effects on BMI were correlated with their maximum R2 differences and interaction effects (0.56 and 0.58, respectively), suggesting high-PGSBMI individuals have highest R2 and increase in PGS effect. Using quantile regression, we show the effect of PGSBMI increases as BMI itself increases, and that these differences in effects are directly related to differences in R2 when stratifying by different covariates. Given significant and replicable evidence for context-specific PGSBMI performance and effects, we investigated ways to increase model performance taking into account nonlinear effects. Machine learning models (neural networks) increased relative model R2 (mean 23%) across datasets. Finally, creating PGSBMI directly from GxAge genome-wide association studies effects increased relative R2 by 7.8%. These results demonstrate that certain covariates, especially those most associated with BMI, significantly affect both PGSBMI performance and effects across diverse cohorts and ancestries, and we provide avenues to improve model performance that consider these effects.

Unraveling the Role of the Tumor Extracellular Matrix to Inform Nanoparticle Design for Nanomedicine

The extracellular matrix (ECM)-and its mechanobiology-regulates key cellular functions that drive tumor growth and development. Accordingly, mechanotherapy is emerging as an effective approach to treat fibrotic diseases such as cancer. Through restoring the ECM to healthy-like conditions, this treatment aims to improve tissue perfusion, facilitating the delivery of chemotherapies. In particular, the manipulation of ECM is gaining interest as a valuable strategy for developing innovative treatments based on nanoparticles (NPs). However, further progress is required; for instance, it is known that the presence of a dense ECM, which hampers the penetration of NPs, primarily impacts the efficacy of nanomedicines. Furthermore, most 2D in vitro studies fail to recapitulate the physiological deposition of matrix components. To address these issues, a comprehensive understanding of the interactions between the ECM and NPs is needed. This review focuses on the main features of the ECM and its complex interplay with NPs. Recent advances in mechanotherapy are discussed and insights are offered into how its combination with nanomedicine can help improve nanomaterials design and advance their clinical translation.

Characterization of LTBP2 mutation causing mitral valve prolapse

Aims

Mitral valve prolapse (MVP) is a common valvular disorder associated with significant morbidity and mortality, with a strong genetic basis. This study aimed to identify a mutation in a family with MVP and to characterize the valve phenotype in LTBP2 knockout (KO) mice.

Methods and results

Exome sequencing and segregation analysis were performed on a large family with MVP. Two mouse strains were generated: a complete KO of the LTBP2 gene and a knockin (KI) of the human mutation. At 6 months, phenotyping was conducted using echocardiography, histology, eye optical coherence tomography, and quantitative polymerase chain reaction analysis for TGF-β signalling targets (periostin/POSTN, RUNX2, and CTGF) in valve tissues. LTBP2 rs117800773 V1506M mutation exhibited segregation with MVP. LTBP2 KO mice had a higher incidence of myxomatous changes by histology (7 of 9 of KO vs. 0 of 7 control animals, P = 0.00186) and echocardiography (7 of 9 vs. 0 of 8, P = 0.0011). LTBP2 KI mice for the human mutation showed a significantly elevated myxomatous histological phenotype (8 of 8 vs. 0 of 9, P = 0.00004) as well as by echocardiography (6 of 8 vs. 0 of 9, P = 0.00123). Knockout mice demonstrated an increase in the depth of the anterior chamber as well as reduced visual acuity. LTBP2 KO mice demonstrated overexpression of both TGF-β signalling targets RUNX2 and periostin (P = 0.0144 and P = 0.001826, respectively).

Conclusion

We report a KO mouse strain with an LTBP2 mutation, demonstrating a valve phenotype, alongside a family with a novel mutation linked to MVP.

Interpretation and classification of FBN1 variants associated with Marfan syndrome: consensus recommendations from the Clinical Genome Resource's FBN1 variant curation expert panel

BACKGROUND

In 2015, the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) developed standardized variant curation guidelines for Mendelian disorders. Although these guidelines have been widely adopted, they are not gene- or disease-specific. To mitigate classification discrepancies, the Clinical Genome Resource FBN1 variant curation expert panel (VCEP) was established in 2018 to develop adaptations to the ACMG/AMP criteria for FBN1 in association with Marfan syndrome.

METHODS

The specific recommendations were developed through literature review, surveys, online expert panel discussions, and pilot testing of a set of 60 different variants. Consensus among experts was considered reached if at least 75% of the members agreed with a given rule specification. The final set of rules received approval from the ClinGen Sequence Variant Interpretation Working Group.

RESULTS

The developed specifications introduce modifications to 14 of the 28 ACMG/AMP evidence criteria and deem 6 criteria non-applicable. Some of these specifications include refining the minor allele frequency thresholds, creating a FBN1-specific flowchart for PVS1, defining functional domains of the protein, developing a point-based system of counting probands and instances of de novo occurrences, recommending a points-based method of accounting for family segregation data, and clarifying the applicable functional assays that should be considered. To date, this VCEP has curated 120 variants which have been deposited to ClinVar with the 3-star review status.

CONCLUSIONS

Establishing specific adaptations for FBN1 has provided a framework to foster greater classification concordance among clinical laboratories, ultimately improving clinical care for patients with Marfan syndrome.

Missense variants of FBN2 associated with congenital arachnodactyly in three Chinese families

Background

Congenital contractural arachnodactyly (CCA) is a rare autosomal dominant disorder caused by pathogenic variants of Fibrillin-2 (FBN2) gene. This study aimed to investigate the variants in three Chinese families with CCA.

Methods

Next-generation sequencing analysis and Sanger sequencing of exons 24-35 of FBN2 (NM_001999.4) were performed on the three CCA pedigrees. The pathogenicity of the variants was assessed using ACMG criteria and predicted using an in-silico program.

Results

A novel heterozygous substitution (NM_001999.4: c.3230G > A; NP_001990.2 p. Cys1077Tyr) was identified in all patients from pedigree A, but not in healthy family members. The variant was found to be pathogenic. Additionally, in pedigree B (NM_001999.4: c.4222G > A; NP_001990.2: p.Asp1408Asn) and C (NM_001999.4: c.3170G > A; NP_001990.2: p.Gly1057Asp), and the previously reported variants were detected. Variants affecting cysteine residues may disrupt disulfide bridging, leading to a weakened microfibril scaffold, resulting in CCA phenotypes. High phenotypic heterogeneity was observed among different families, and there was little correlation between the genotype and phenotype.

Conclusion

This study describes three large families with CCA caused by missense variants in the FBN2 gene. Phenotypic variations were observed among different pedigree groups, and further research is needed to investigate the underlying reasons for these variations.

Mechanisms of assembly and remodelling of the extracellular matrix

The extracellular matrix (ECM) is the complex meshwork of proteins and glycans that forms the scaffold that surrounds and supports cells. It exerts key roles in all aspects of metazoan physiology, from conferring physical and mechanical properties on tissues and organs to modulating cellular processes such as proliferation, differentiation and migration. Understanding the mechanisms that orchestrate the assembly of the ECM scaffold is thus crucial to understand ECM functions in health and disease. This Review discusses novel insights into the compositional diversity of matrisome components and the mechanisms that lead to tissue-specific assemblies and architectures tailored to support specific functions. The Review then highlights recently discovered mechanisms, including post-translational modifications and metabolic pathways such as amino acid availability and the circadian clock, that modulate ECM secretion, assembly and remodelling in homeostasis and human diseases. Last, the Review explores the potential of 'matritherapies', that is, strategies to normalize ECM composition and architecture to achieve a therapeutic benefit.

National registry insights on genetic aortopathies and thoracic endovascular aortic interventions

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) in patients with genetic aortopathies (GA) is controversial, given concerns of durability. We describe characteristics and outcomes after TEVAR in patients with GA.

METHODS

All patients undergoing TEVAR between 2010 and 2023 in the Vascular Quality Iniatitive were identified and categorized as having a GA or not. Demographics, baseline, and procedural characteristics were compared among groups. Multivariable logistic regression was used to evaluate the independent association of GA with postoperative outcomes. Kaplan-Meier methods and multivariable Cox regression analyses were used to evaluate 5-year survival and 2-year reinterventions.

RESULTS

Of 19,340 patients, 304 (1.6%) had GA (87% Marfan syndrome, 9% Loeys-Dietz syndrome, and 4% vascular Ehlers-Danlos syndrome). Compared with patients without GA, patients with GA were younger (50 years [interquartile range, 37-72 years] vs 70 years [interquartile range, 61-77 years]), more often presented with acute dissection (28% vs 18%), postdissection aneurysm (48% vs 17%), had a symptomatic presentation (50% vs 39%), and were less likely to have degenerative aneurysms (18% vs 47%) or penetrating aortic ulcer (and intramural hematoma) (3% vs 13%) (all P < .001). Patients with GA were more likely to have prior repair of the ascending aorta/arch (open, 56% vs 11% [P < .001]; endovascular, 5.6% vs 2.1% [P = .017]) or the descending thoracic aorta (open, 12% vs 2% [P = .007]; endovascular, 8.2% vs 3.6% [P = .011]). No significant differences were found in prior abdominal suprarenal repairs; however, patients with GA had more prior open infrarenal repairs (5.3% vs 3.2%), but fewer prior endovascular infrarenal repairs (3.3% vs 5.5%) (all P < .05). After adjusting for demographics, comorbidities, and disease characteristics, patients with GA had similar odds of perioperative mortality (4.6% vs 7.0%; adjusted odds ratio [aOR], 1.1; 95% confidence interval [CI], 0.57-1.9; P = .75), any in-hospital complication (26% vs 23%; aOR, 1.24; 95% CI, 0.92-1.6; P = .14), or in-hospital reintervention (13% vs 8.3%; aOR, 1.25; 95% CI, 0.84-1.80; P = .25) compared with patients without GA. However, patients with GA had a higher likelihood of postoperative vasopressors (33% vs 27%; aOR, 1.44; 95% CI, 1.1-1.9; P = .006) and transfusion (25% vs 23%; aOR, 1.39; 95% CI, 1.03-1.9; P = .006). The 2-year reintervention rates were higher in patients with GA (25% vs 13%; adjusted hazard ratio, 1.99; 95% CI, 1.4-2.9; P < .001), but 5-year survival was similar (81% vs 74%; adjusted hazard ratio, 1.02; 95% CI, 0.70-1.50; P = .1).

CONCLUSIONS

TEVAR for patients with GA seemed to be safe initially, with similar odds for in-hospital complications, in-hospital reinterventions, and perioperative mortality, as well as similar hazards for 5-year mortality compared with patients without GA. However, patients with GA had higher 2-year reintervention rates. Future studies should assess long-term durability after TEVAR compared with the recommended open repair to appropriately weigh the risks and benefits of endovascular treatment in patients with GA.

Precision epigenetic editing: Technological advances, enduring challenges, and therapeutic applications

The epigenome is a complex framework through which gene expression is precisely and flexibly modulated to incorporate heritable memory and responses to environmental stimuli. It governs diverse cellular processes, including cell fate, disease, and aging. The need to understand this system and precisely control gene expression outputs for therapeutic purposes has precipitated the development of a diverse set of epigenetic editing tools. Here, we review the existing toolbox for targeted epigenetic editing, technical considerations of the current technologies, and opportunities for future development. We describe applications of therapeutic epigenetic editing and their potential for treating disease, with a discussion of ongoing delivery challenges that impede certain clinical interventions, particularly in the brain. With simultaneous advancements in available engineering tools and appropriate delivery technologies, we predict that epigenetic editing will increasingly cement itself as a powerful approach for safely treating a wide range of disorders in all tissues of the body.

Pilot study exploring artificial intelligence for facial-image-based diagnosis of Marfan syndrome

Background

Marfan Syndrome (MFS), a genetic disorder impacting connective tissue, manifests in a wide array of phenotypes which can affect numerous bodily systems, especially the thoracic aorta. The syndrome often presents distinct facial features that potentially allow for diagnostic clinical recognition. Herein, we explore the potential of Artificial Intelligence (AI) in diagnosing Marfan syndrome from ordinary facial images, as assessed by overall accuracy, F1 score, and area under the ROC curve.

Methods

This study explores the utilization of Convolutional Neural Networks (CNN) for MFS identification through facial images, offering a novel, non-invasive, automated, and computerized diagnostic approach. The research examines the accuracy of Neural Networks in the diagnosis of Marfan Disease from ordinary on-line facial images. The model was trained on 80 % of 672 facial images (182 Marfan and 490 control). The other 20 % of images were used as the test set.

Results

Overall accuracy was 98.5 % (0 % false positive, 2 % false negative). F1 score was 97 % for Marfan facies and 99 % for non-Marfan facies. Area under the ROC curve was 100 %.

Conclusion

An Artificial Intelligence (AI) program was able to distinguish Marfan from non-Marfan facial images (from ordinary on-line photographs) with an extremely high degree of accuracy. Clinical usefulness of this program is anticipated. However, due to the limited and preliminary nature of this work, this should be viewed as only a pilot study.

Challenges in prompt identification and surgical correction of Marfan Syndrome aortic disease in a middle-income country: a case series study

BACKGROUND

Marfan Syndrome is an autosomal dominant disease caused by pathogenetic variants in the FBN1 gene. The progressive dilatation of the aorta and the potential risk of acute aortic syndromes influence the prognosis of these patients. We aim to describe population characteristics, long-term survival, and re-intervention patterns in patients who underwent aortic surgery with a previously confirmed clinical diagnosis of Marfan Syndrome in a middle-income country.

METHODS

A retrospective single-center case series study was conducted. All Marfan Syndrome patients who underwent aortic procedures from 2004 until 2021 were included. Qualitative variables were frequency-presented, while quantitative ones adopted mean ± standard deviation. A subgroup analysis between elective and emergent procedures was conducted. Kaplan-Meier plots depicted cumulative survival and re-intervention-free. Control appointments and government data tracked out-of-hospital mortality.

RESULTS

Fifty patients were identified. The mean age was 38.79 ± 14.41 years, with a male-to-female ratio of 2:1. Common comorbidities included aortic valve regurgitation (66%) and hypertension (50%). Aortic aneurysms were observed in 64% without dissection and 36% with dissection. Surgical procedures comprised elective (52%) and emergent cases (48%). The most common surgery performed was the David procedure (64%), and the Bentall procedure (14%). The in-hospital mortality rate was 4%. Complications included stroke (10%), and acute kidney injury (6%). The average follow-up was 8.88 ± 5.78 years. Survival rates at 5, 10, and 15 years were 89%, 73%, and 68%, respectively. Reintervention rates at 1, 2.5, and 5 years were 10%, 14%, and 17%, respectively. The emergent subgroup was younger (37.58 ± 14.49 years), had the largest number of Stanford A aortic dissections, presented hemodynamic instability (41.67%), and had a higher requirement of reinterventions in the first 5 years of follow-up (p = 0.030).

CONCLUSION

In our study, surveillance programs played a pivotal role in sustaining high survival rates and identifying re-intervention requirements. However, challenges persist, as 48% of the patients required emergent surgery. Despite not affecting survival rates, a greater requirement for reinterventions was observed, emphasizing the necessity of timely diagnosis. Enhanced educational initiatives for healthcare providers and increased patient involvement in follow-up programs are imperative to address these concerns.

Diagnosis of Marfan Syndrome Following Progressive Myopia and Secondary Lens-Induced Angle Closure Crisis

Marfan syndrome (MFS) is a well-described genetic connective tissue disease that heightens the risk of cardiovascular, ocular, pulmonary, and other emergencies in affected individuals. The wide range of phenotypic presentations, spanning from mild, chronic, and asymptomatic to acute and life-threatening, can pose challenges in diagnosing MFS when disease manifestations are subtle. We report a pathogenetic variant of MFS characterized by subtle systemic findings that was identified only after the patient presented with visual changes and pain associated with angle closure, despite a medical history indicating other pathologies linked to this condition. This case underscores the importance of recognizing the varied and sometimes subtle clinical features of MFS. Vigilance in identifying the constellation of findings associated with MFS can enhance its diagnosis and treatment outcomes by enabling appropriate and timely referrals for prophylactic evaluation and care to address potentially life-threatening complications.

Pulmonary alveolar microlithiasis combined with gastric mucosal calcification: a case report

Background

Pulmonary alveolar microlithiasis (PAM) is a rare disease whose clinical and imaging manifestations are non-specific, characterized by the deposition of microliths, which primarily consist of calcium and phosphorus, within the alveoli. In the cases of PAM, patients combined with calcification of other organs such as gastric mucosal calcification are less common.

Case presentation

A 59-year-old woman was admitted to our hospital due to cough producing white, foamy sputum, accompanied by dyspnea and fever for 20 days. The CT scan showed diffuse ground-glass opacities and calcification of the gastric mucosa. Lung tissue biopsy revealed the presence of calcification and granulomatous foreign bodies in the interstitium and alveolar cavity. In the later stages, she developed painful skin petechiae. For this patient, the diagnosis of PAM, gastric mucosal calcification, and purpura fulminans was made. However, the genetic test results hinted that the patient and her son had a heterozygous mutation in the FBN1 gene, but her daughter's genetic test results were normal. Although the patient received anti-infection treatment, steroids, and oxygen therapy, her condition did not improve.

Conclusion

We reported a rare case of PAM combined with calcification of other organs and purpura fulminans. Treatment of steroids did not show any benefit. The causative mechanism and effective treatment of this disease remain unclear. More treatments need to be explored.

Risk factors affecting polygenic score performance across diverse cohorts

Apart from ancestry, personal or environmental covariates may contribute to differences in polygenic score (PGS) performance. We analyzed effects of covariate stratification and interaction on body mass index (BMI) PGS (PGSBMI) across four cohorts of European (N=491,111) and African (N=21,612) ancestry. Stratifying on binary covariates and quintiles for continuous covariates, 18/62 covariates had significant and replicable R2 differences among strata. Covariates with the largest differences included age, sex, blood lipids, physical activity, and alcohol consumption, with R2 being nearly double between best and worst performing quintiles for certain covariates. 28 covariates had significant PGSBMI-covariate interaction effects, modifying PGSBMI effects by nearly 20% per standard deviation change. We observed overlap between covariates that had significant R2 differences among strata and interaction effects - across all covariates, their main effects on BMI were correlated with their maximum R2 differences and interaction effects (0.56 and 0.58, respectively), suggesting high-PGSBMI individuals have highest R2 and increase in PGS effect. Using quantile regression, we show the effect of PGSBMI increases as BMI itself increases, and that these differences in effects are directly related to differences in R2 when stratifying by different covariates. Given significant and replicable evidence for context-specific PGSBMI performance and effects, we investigated ways to increase model performance taking into account non-linear effects. Machine learning models (neural networks) increased relative model R2 (mean 23%) across datasets. Finally, creating PGSBMI directly from GxAge GWAS effects increased relative R2 by 7.8%. These results demonstrate that certain covariates, especially those most associated with BMI, significantly affect both PGSBMI performance and effects across diverse cohorts and ancestries, and we provide avenues to improve model performance that consider these effects.

Ocular Involvement and Treatment Pattern in Korean Patients with Marfan Syndrome: A Population-Based Study

PURPOSE

This study aimed to investigate the incidence and prevalence of, and treatment patterns for ocular complications in Korean patients with Marfan syndrome.

METHODS

Incidence and prevalence of Marfan syndrome was calculated from 2010 to 2018, based on data from the Korean National Health Insurance Service (KNHIS). Diagnosis codes (for cataract, ectopia lentis, retinal detachment, etc.) and surgery reimbursement codes (lensectomy, phacoemulsification, buckling, vitrectomy, etc.) in the patients with Marfan syndrome were retrieved by complete enumeration of the data.

RESULTS

The annual prevalence of Marfan syndrome adjusted by age and sex was gradually increased from 2.44 per 100,000 in 2010 to 4.36 per 100,000 in 2018. The age group of 10-19 years showed the highest prevalence. The prevalence of ectopia lentis was 21.7%, of whom 43.0% underwent surgeries. Surgery for RD was performed in 253 (14.1%) of 2044 patients during the study period.

CONCLUSION

Although the most prevalent ophthalmologic manifestation was ectopia lentis, total prevalence rate of RD was more than 10% in the study period; thus, regular fundus examination is recommended for the patients with Marfan syndrome.

Regnase-1 overexpression as a therapeutic approach of Marfan syndrome

Rupture or dissection of thoracic aortic aneurysms is still the leading cause of death for patients diagnosed with Marfan syndrome. Inflammation and matrix digestion regulated by matrix metalloproteases (MMPs) play a major role in the pathological remodeling of the aortic media. Regnase-1 is an endoribonuclease shown to cleave the mRNA of proinflammatory cytokines, such as interleukin-6. Considering the major anti-inflammatory effects of regnase-1, here, we aimed to determine whether adeno-associated virus (AAV)-mediated vascular overexpression of the protein could provide protection from the development and progression of aortic aneurysms in Marfan syndrome. The overexpression of regnase-1 resulted in a marked decrease in inflammatory parameters and elastin degradation in aortic smooth muscle cells in vitro. Intravenous injection of a vascular-targeted AAV vector resulted in the efficient transduction of the aortic wall and overexpression of regnase-1 in a murine model of Marfan syndrome, associated with lower circulating levels of proinflammatory cytokines and decreased MMP expression and activity. Regnase-1 overexpression strongly improved elastin architecture in the media and reduced aortic diameter at distinct locations. Therefore, AAV-mediated regnase-1 overexpression may represent a novel gene therapy approach for inhibiting aortic aneurysms in Marfan syndrome.

Neurotrophic Keratopathy in Marfan Syndrome Patient After Micropulse Transscleral Cyclophotocoagulation: A Call for Risk Stratification

BACKGROUND Micropulse transscleral cyclophotocoagulation is a non-invasive, widely employed procedure that uses diode laser to target the ciliary body to lower the intraocular pressure. Despite its acknowledged efficacy, certain complications are recognized, with neurotrophic keratopathy being a rare yet serious consequence. This report seeks to shed light on a potential high-risk subgroup susceptible to neurotrophic keratopathy, exemplified by our patient with Marfan syndrome, a condition characterized by thin sclera. CASE REPORT Our patient, who was confirmed to have Marfan syndrome with pseudophakic glaucoma, underwent micropulse transscleral cyclophotocoagulation due to high intraocular pressure bilaterally and subsequently quickly manifested neurotrophic keratopathy in both eyes postoperatively. Swift initiation of management involved a comprehensive approach, including topical antibiotics, preservative-free lubrication, medroxyprogesterone acetate 1%, serum balanced salt solution (BSS) 50%, and the application of bandage contact lenses to expedite healing. Fortunately, the left eye demonstrated resolution within 10 days, while the right eye exhibited delayed healing, leading to subsequent scarring. CONCLUSIONS This report highlights the critical importance of recognizing populations predisposed to neurotrophic keratopathy before subjecting them to micropulse transscleral cyclophotocoagulation. Such awareness allows for the fine-tuning of procedural parameters, offering a strategic approach to mitigate the risk of neurotrophic keratopathy development. By further exploring and recognizing potential risk factors, clinicians can enhance patient outcomes and refine the safety profile of micropulse transscleral cyclophotocoagulation.

Identification and expression analysis of Oxfibrillin gene involved in the regeneration process of Ophryotrocha xiamen (Annelida, Dorcilleidae)

Regeneration of lost body parts is a widespread phenomenon across annelids. However, the molecular inducers of the cell sources for this reparative morphogenesis have not been identified. We have identified a regeneration-related gene Oxfibrillin from the transcriptome analysis of a polychaeta, Ophryotrocha xiamen, which is found to be a well-suited model to study the mechanisms of regeneration. Fibrillins are large glycoproteins that assemble to form the microfibrils and regulate growth factors or other transfer processes. Here, we obtained the 31,274 bp genomic DNA sequences of Oxfibrillin. The coding sequence length was 5784 bp encoding 1927 amino acids with a VWD domain, EGF/cb-EGF domains, a TR domain, and a transmembrane domain. Oxfibrillin was positioned within the subgroup of invertebrates and showed low scores for homology to mammalian fibrillin. In gene expression analysis, Oxfibrillin genes were constantly upregulated during the early regeneration process and then remained stable until the formation of the complete tail which indicated that it might be a vital factor to affect posterior regeneration process. Therefore, the Oxfibrillin of O. xiamen might play important roles in the regeneration process.

Marfanoid to Mortality: A Case Report on Sudden Cardiac Death Due to Aortic Dissection in a Young Male With Marfanoid Habitus

This compelling case study unravels a tragic narrative of a 40-year-old male with Marfanoid habitus, navigating the intricate web of Marfan syndrome (MFS) and succumbing to the devastating complications of aortic dissection. The patient's journey underscores the challenges in managing this rare connective tissue disorder, emphasizing the critical interplay between genetic predisposition and cardiovascular pathology. Moreover, the lack of immediate operative intervention due to the critical condition emphasizes the crucial need for timely diagnosis and intervention. The journey from genetic mutation to cardiovascular complications in MFS or related marfanoid habitus is complex and multifaceted. This case study aims to navigate this intricate path, emphasizing the need for a nuanced understanding of the underlying molecular and structural changes. Furthermore, it reinforces the critical role of ongoing cardiovascular monitoring and surgical interventions to prolong survival and enhance the quality of life for individuals grappling with the challenges posed by MFS or related habitus.

Identification and phenotypic analysis of novel LTBP2 mutations in a Chinese cohort with congenital ectopia lentis

Purpose

To evaluate the frequency of LTBP2 mutations and to elaborate on LTBP2-related clinical phenotypes in a Chinese congenital ectopia lentis (CEL) cohort.

Methods

In total, 145 Chinese probands with CEL were recruited for this study and underwent ocular and systemic examinations. Whole-exome sequencing was used to identify mutations, and Sanger sequencing and bioinformatics analysis were further performed to verify pathogenic mutations.

Results

Overall, biallelic mutations in LTBP2 involving eight novel mutations (c.4370-7_4370-9delTCT, c.4370-5C>G, c.3452G>A, c.2253delG, c.4114T>C, c.1251G>A, c.4760G>A, and c.620G>A) were identified in four CEL probands (4/145, 2.76%). Patients with LTBP2 mutations were characterized by a megalocornea, spherophakia, high myopia, and glaucoma instead of a flat cornea, high corneal astigmatism, cardiovascular and skeletal abnormalities that were reported in other gene mutations. A novel homozygous frameshift mutation was detected, and this type of mutation was found to cause more complicated ocular symptoms than others, ranging from the anterior segment to the fundus.

Conclusion

This study reported the mutation frequency of the LTBP2 gene in a Chinese CEL cohort and provided novel insight into LTBP2-related genotype-phenotype associations in CEL.

Clinical and genetic screening in a large Iranian family with Marfan syndrome: A case study

Background and Aims

Marfan syndrome (MFS) is an autosomal dominant genetic disorder caused by pathogenic variants of the fibrillin-1-encoding FBN1 gene that commonly affects the cardiovascular, skeletal, and ocular systems. This study aimed to evaluate the clinical features and genetic causes of the MFS phenotype in a large Iranian family.

Methods

Seventeen affected family members were examined clinically by cardiologists and ophthalmologists. The proband, a 48-year-old woman with obvious signs of MFS, her DNA sample subjected to whole-exome sequencing (WES). The candidate variant was validated by bidirectional sequencing of proband and other available family members. In silico analysis and molecular modeling were conducted to determine the pathogenic effects of the candidate variants.

Results

The most frequent cardiac complications are mitral valve prolapse and regurgitation. Ophthalmic examination revealed iridodonesis and ectopic lentis. A heterozygous missense variant (c.2179T>C/p.C727R) in exon 19 of FBN1 gene was identified and found to cosegregate with affected family members. Its pathogenicity has been predicted using several in silico predictive algorithms. Molecular docking analysis indicated that the variant might affect the binding affinity between FBN1 and LTBP1 proteins by impairing disulfide bond formation.

Conclusion

Our report expands the spectrum of the Marfan phenotype by providing details of its clinical manifestations and disease-associated molecular changes. It also highlights the value of WES in genetic diagnosis and contributes to genetic counseling in families with MFS.

Genetic Risk Factors Related to Coronary Artery Disease and Role of Transforming Growth Factor Beta 1 Polymorphisms

Coronary artery disease (CAD) is one of the leading causes of mortality globally and has long been known to be heritable; however, the specific genetic factors involved have yet to be identified. Recent advances have started to unravel the genetic architecture of this disease and set high expectations about the future use of novel susceptibility variants for its prevention, diagnosis, and treatment. In the past decade, there has been major progress in this area. New tools, like common variant association studies, genome-wide association studies, meta-analyses, and genetic risk scores, allow a better understanding of the genetic risk factors driving CAD. In recent years, researchers have conducted further studies that confirmed the role of numerous genetic factors in the development of CAD. These include genes that affect lipid and carbohydrate metabolism, regulate the function of the endothelium and vascular smooth muscles, influence the coagulation system, or affect the immune system. Many CAD-associated single-nucleotide polymorphisms have been identified, although many of their functions are largely unknown. The inflammatory process that occurs in the coronary vessels is very important in the development of CAD. One important mediator of inflammation is TGFβ1. TGFβ1 plays an important role in the processes leading to CAD, such as by stimulating macrophage and fibroblast chemotaxis, as well as increasing extracellular matrix synthesis. This review discusses the genetic risk factors related to the development of CAD, with a particular focus on polymorphisms of the transforming growth factor β (TGFβ) gene and its receptor.

Marfan Syndrome: Enhanced Diagnostic Tools and Follow-up Management Strategies

Marfan syndrome (MFS) is a rare inherited autosomic disorder, which encompasses a variety of systemic manifestations caused by mutations in the Fibrillin-1 encoding gene (FBN1). Cardinal clinical phenotypes of MFS are highly variable in terms of severity, and commonly involve cardiovascular, ocular, and musculoskeletal systems with a wide range of manifestations, such as ascending aorta aneurysms and dissection, mitral valve prolapse, ectopia lentis and long bone overgrowth, respectively. Of note, an accurate and prompt diagnosis is pivotal in order to provide the best treatment to the patients as early as possible. To date, the diagnosis of the syndrome has relied upon a systemic score calculation as well as DNA mutation identification. The aim of this review is to summarize the latest MFS evidence regarding the definition, differences and similarities with other connective tissue pathologies with severe systemic phenotypes (e.g., Autosomal dominant Weill-Marchesani syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome) and clinical assessment. In this regard, the management of MFS requires a multidisciplinary team in order to accurately control the evolution of the most severe and potentially life-threatening complications. Based on recent findings in the literature and our clinical experience, we propose a multidisciplinary approach involving specialists in different clinical fields (i.e., cardiologists, surgeons, ophthalmologists, orthopedics, pneumologists, neurologists, endocrinologists, geneticists, and psychologists) to comprehensively characterize, treat, and manage MFS patients with a personalized medicine approach.

Candidate genes for obstructive sleep apnea in non-syndromic children with craniofacial dysmorphisms - a narrative review

Pediatric obstructive sleep apnea (POSA) is a complex disease with multifactorial etiopathogenesis. The presence of craniofacial dysmorphisms influencing the patency of the upper airway is considered a risk factor for POSA development. The craniofacial features associated with sleep-related breathing disorders (SRBD) - craniosynostosis, retrognathia and micrognathia, midface and maxillary hypoplasia - have high heritability and, in a less severe form, could be also found in non-syndromic children suffering from POSA. As genetic factors play a role in both POSA and craniofacial dysmorphisms, we hypothesize that some genes associated with specific craniofacial features that are involved in the development of the orofacial area may be also considered candidate genes for POSA. The genetic background of POSA in children is less explored than in adults; so far, only one genome-wide association study for POSA has been conducted; however, children with craniofacial disorders were excluded from that study. In this narrative review, we discuss syndromes that are commonly associated with severe craniofacial dysmorphisms and a high prevalence of sleep-related breathing disorders (SRBD), including POSA. We also summarized information about their genetic background and based on this, proposed 30 candidate genes for POSA affecting craniofacial development that may play a role in children with syndromes, and identified seven of these genes that were previously associated with craniofacial features risky for POSA development in non-syndromic children. The evidence-based approach supports the proposition that variants of these candidate genes could lead to POSA phenotype even in these children, and, thus, should be considered in future research in the general pediatric population.

Case report: marfan syndrome (MFS) mimicking cutaneous vasculitis

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder caused by variants in the extracellular microfibril fibrillin (FBN1) gene. Here we report an FBN1 variant in a child with an unusual skin rash mimicking cutaneous vasculitis, and mild aortic root dilatation. The case was complicated by lack of typical skeletal MFS phenotype; and severe needle phobia preventing any blood testing for workup of suspected vasculitis. Therefore inflammatory markers, autoantibody profile and general hematology/biochemistry results were unknown. Diagnosis of MFS was made via genetic testing of a saliva sample alone using a next-generation sequencing (NGS) targeted gene panel designed to screen for monogenic forms of vasculitis and noninflammatory vasculopathic mimics. This revealed the patient was heterozygous for a pathogenic frameshift variant in FBN1; NM_000138, c.1211delC, p.(Pro404Hisfs*44), predicted to cause premature protein truncation leading to loss of function. The variant has not been detected in control populations and has previously been detected in individuals with MFS. This rapid diagnosis significantly impacted the patient management: avoidance of invasive investigations; avoidance of unnecessary immunosuppression; facilitating genetic counselling of the index case and family; and directly informing lifelong monitoring and ongoing treatment for aortic root involvement from MFS. This case further emphasizes the diagnostic utility of NGS early in the diagnostic workup of paediatric patients referred with suspected vasculitis, and we emphasize that MFS can present with cutaneous vasculitic-like features in the absence of the typical Marfanoid skeletal phenotype.

Fibrillin-1 regulates endothelial sprouting during angiogenesis

Fibrillin-1 is an extracellular matrix protein that assembles into microfibrils which provide critical functions in large blood vessels and other tissues. Mutations in the fibrillin-1 gene are associated with cardiovascular, ocular, and skeletal abnormalities in Marfan syndrome. Here, we reveal that fibrillin-1 is critical for angiogenesis which is compromised by a typical Marfan mutation. In the mouse retina vascularization model, fibrillin-1 is present in the extracellular matrix at the angiogenic front where it colocalizes with microfibril-associated glycoprotein-1, MAGP1. In Fbn1C1041G/+ mice, a model of Marfan syndrome, MAGP1 deposition is reduced, endothelial sprouting is decreased, and tip cell identity is impaired. Cell culture experiments confirmed that fibrillin-1 deficiency alters vascular endothelial growth factor-A/Notch and Smad signaling which regulate the acquisition of endothelial tip cell/stalk cell phenotypes, and we showed that modulation of MAGP1 expression impacts these pathways. Supplying the growing vasculature of Fbn1C1041G/+ mice with a recombinant C-terminal fragment of fibrillin-1 corrects all defects. Mass spectrometry analyses showed that the fibrillin-1 fragment alters the expression of various proteins including ADAMTS1, a tip cell metalloprotease and matrix-modifying enzyme. Our data establish that fibrillin-1 is a dynamic signaling platform in the regulation of cell specification and matrix remodeling at the angiogenic front and that mutant fibrillin-1-induced defects can be rescued pharmacologically using a C-terminal fragment of the protein. These findings, identify fibrillin-1, MAGP1, and ADAMTS1 in the regulation of endothelial sprouting, and contribute to our understanding of how angiogenesis is regulated. This knowledge may have critical implications for people with Marfan syndrome.

Biology of mitral valve prolapse: from general mechanisms to advanced molecular patterns-a narrative review

Mitral valve prolapse (MVP) represents the most frequent cause of primary mitral regurgitation. For several years, biological mechanisms underlying this condition attracted the attention of investigators, trying to identify the pathways responsible for such a peculiar condition. In the last ten years, cardiovascular research has moved from general biological mechanisms to altered molecular pathways activation. Overexpression of TGF-β signaling, for instance, was shown to play a key role in MVP, while angiotensin-II receptor blockade was found to limit MVP progression by acting on the same signaling pathway. Concerning extracellular matrix organization, the increased valvular interstitial cells density and dysregulated production of catalytic enzymes (matrix metalloproteinases above all) altering the homeostasis between collagen, elastin and proteoglycan components, have been shown to possibly provide a mechanistic basis contributing to the myxomatous MVP phenotype. Moreover, it has been observed that high levels of osteoprotegerin may contribute to the pathogenesis of MVP by increasing collagen deposition in degenerated mitral leaflets. Although MVP is believed to represent the result of multiple genetic pathways alterations, it is important to distinguish between syndromic and non-syndromic conditions. In the first case, such as in Marfan syndrome, the role of specific genes has been clearly identified, while in the latter a progressively increasing number of genetic loci have been thoroughly investigated. Moreover, genomics is gaining more interest as potential disease-causing genes and loci possibly associated with MVP progression and severity have been identified. Animal models could be of help in better understanding the molecular basis of MVP, possibly providing sufficient information to tackle specific mechanisms aimed at slowing down MVP progression, therefore developing non-surgical therapies impacting on the natural history of this condition. Although continuous progress has been made in this field, further translational studies are advocated to improve our knowledge of biological mechanisms underlying MVP development and progression.

Fibrillin microfibril structure identifies long-range effects of inherited pathogenic mutations affecting a key regulatory latent TGFβ-binding site

Genetic mutations in fibrillin microfibrils cause serious inherited diseases, such as Marfan syndrome and Weill-Marchesani syndrome (WMS). These diseases typically show major dysregulation of tissue development and growth, particularly in skeletal long bones, but links between the mutations and the diseases are unknown. Here we describe a detailed structural analysis of native fibrillin microfibrils from mammalian tissue by cryogenic electron microscopy. The major bead region showed pseudo eightfold symmetry where the amino and carboxy termini reside. On the basis of this structure, we show that a WMS deletion mutation leads to the induction of a structural rearrangement that blocks interaction with latent TGFβ-binding protein-1 at a remote site. Separate deletion of this binding site resulted in the assembly of shorter fibrillin microfibrils with structural alterations. The integrin α_vβ₃-binding site was also mapped onto the microfibril structure. These results establish that in complex extracellular assemblies, such as fibrillin microfibrils, mutations may have long-range structural consequences leading to the disruption of growth factor signaling and the development of disease.

Distinct Mechanisms of β-Arrestin-Biased Agonist and Blocker of AT1R in Preventing Aortic Aneurysm and Associated Mortality

BACKGROUND

Aortic aneurysm (AA) is a "silent killer" human disease with no effective treatment. Although the therapeutic potential of various pharmacological agents have been evaluated, there are no reports of β-arrestin-biased AT1R (angiotensin-II type-1 receptor) agonist (TRV027) used to prevent the progression of AA.

METHODS

We tested the hypothesis that TRV027 infusion in AngII (angiotensin II)-induced mouse model of AA prevents AA. High-fat-diet-fed ApoE (apolipoprotein E gene)-null mice were infused with AngII to induce AA and co-infused with TRV027 and a clinically used AT1R blocker Olmesartan to prevent AA. Aortas explanted from different ligand infusion groups were compared with assess different grades of AA or lack of AA.

RESULTS

AngII produced AA in ≈67% male mice with significant mortality associated with AA rupture. We observed ≈13% mortality due to aortic arch dissection without aneurysm in male mice. AngII-induced AA and mortality was prevented by co-infusion of TRV027 or Olmesartan, but through different mechanisms. In TRV027 co-infused mice aortic wall thickness, elastin content, new DNA, and protein synthesis were higher than untreated and Olmesartan co-infused mice. Co-infusion with both TRV027 and Olmesartan prevented endoplasmic reticulum stress, fibrosis, and vasomotor hyper responsiveness.

CONCLUSIONS

TRV027-engaged AT1R prevented AA and associated mortality by distinct molecular mechanisms compared with the AT1R blocker, Olmesartan. Developing novel β-arrestin-biased AT1R ligands may yield promising drugs to combat AA.

What Can RNA-Based Therapy Do for Monogenic Diseases?

The use of RNA-based approaches to treat monogenic diseases (i.e., hereditary disorders caused by mutations in single genes) has been developed on different fronts. One approach uses small antisense oligonucleotides (ASOs) to modulate RNA processing at various stages; namely, to enhance correct splicing, to stimulate exon skipping (to exclude premature termination codon variants), to avoid undesired messenger RNA (mRNA) transcript degradation via the nonsense-mediated decay (NMD) pathway, or to induce mRNA degradation where they encode toxic proteins (e.g., in dominant diseases). Another approach consists in administering mRNA, which, like gene therapy, is a mutation-agnostic approach with potential application to any recessive monogenic disease. This is simpler than gene therapy because instead of requiring targeting of the nucleus, the mRNA only needs to be delivered to the cytoplasm. Although very promising (as demonstrated by COVID-19 vaccines), these approaches still have potential for optimisation, namely regarding delivery efficiency, adverse drug reactions and toxicity.

Stem Cell-Based Therapeutic Approaches in Genetic Diseases

Stem cells, which can self-renew and differentiate into different cell types, have become the keystone of regenerative medicine due to these properties. With the achievement of superior clinical results in the therapeutic approaches of different diseases, the applications of these cells in the treatment of genetic diseases have also come to the fore. Foremost, conventional approaches of stem cells to genetic diseases are the first approaches in this manner, and they have brought safety issues due to immune reactions caused by allogeneic transplantation. To eliminate these safety issues and phenotypic abnormalities caused by genetic defects, firstly, basic genetic engineering practices such as vectors or RNA modulators were combined with stem cell-based therapeutic approaches. However, due to challenges such as immune reactions and inability to target cells effectively in these applications, advanced molecular methods have been adopted in ZFN, TALEN, and CRISPR/Cas genome editing nucleases, which allow modular designs in stem cell-based genetic diseases' therapeutic approaches. Current studies in genetic diseases are in the direction of creating permanent treatment regimens by genomic manipulation of stem cells with differentiation potential through genome editing tools. In this chapter, the stem cell-based therapeutic approaches of various vital genetic diseases were addressed wide range from conventional applications to genome editing tools.

Dissection of mendelian predisposition and complex genetic architecture of craniovertebral junction malformation

The craniovertebral junction (CVJ) is an anatomically complex region of the axial skeleton that provides protection of the brainstem and the upper cervical spinal cord. Structural malformation of the CVJ gives rise to life-threatening neurological deficits, such as quadriplegia and dyspnea. Unfortunately, genetic studies on human subjects with CVJ malformation are limited and the pathogenesis remains largely elusive. In this study, we recruited 93 individuals with CVJ malformation and performed exome sequencing. Manual interpretation of the data identified three pathogenic variants in genes associated with Mendelian diseases, including CSNK2A1, MSX2, and DDX3X. In addition, the contribution of copy number variations (CNVs) to CVJ malformation was investigated and three pathogenic CNVs were identified in three affected individuals. To further dissect the complex mutational architecture of CVJ malformation, we performed a gene-based rare variant association analysis utilizing 4371 in-house exomes as control. Rare variants in LGI4 (carrier rate = 3.26%, p = 3.3 × 10^-5) and BEST1 (carrier rate = 5.43%, p = 5.77 × 10^-6) were identified to be associated with CVJ malformation. Furthermore, gene set analyses revealed that extracellular matrix- and RHO GTPase-associated biological pathways were found to be involved in the etiology of CVJ malformation. Overall, we comprehensively dissected the genetic underpinnings of CVJ malformation and identified several novel disease-associated genes and biological pathways.

Loss of Function TGFBR2 Variant as a Contributing Factor in Generalized Pustular Psoriasis and Adult-Onset Immunodeficiency

BACKGROUND

Generalized pustular psoriasis (GPP; MIM 614204) is a rare multisystemic autoinflammatory disease, characterized by episodes of acute generalized erythema and scaling developed with the spread of numerous sterile pustules. Adult-onset immunodeficiency syndrome (AOID) with anti-interferon-γ autoantibodies is an immunodeficiency disorder associated with disruptive IFN-γ signaling.

METHODS

Clinical examination and whole exome sequencing (WES) were performed on 32 patients with pustular psoriasis phenotypes and 21 patients with AOID with pustular skin reaction. Histopathological and immunohistochemical studies were performed.

RESULTS

WES identified four Thai patients presenting with similar pustular phenotypes-two with a diagnosis of GPP and the other two with AOID-who were found to carry the same rare TGFBR2 frameshift mutation c.458del; p.Lys153SerfsTer35, which is predicted to result in a marked loss of functional TGFBR2 protein. The immunohistochemical studied showed overexpression of IL1B, IL6, IL17, IL23, IFNG, and KRT17, a hallmark of psoriatic skin lesions. Abnormal TGFB1 expression was observed in the pustular skin lesion of an AOID patient, suggesting disruption to TGFβ signaling is associated with the hyperproliferation of the psoriatic epidermis.

CONCLUSIONS

This study implicates disruptive TGFBR2-mediated signaling, via a shared truncating variant, c.458del; p.Lys153SerfsTer35, as a "predisposing risk factor" for GPP and AOID.

Endothelial dysfunction in Marfan syndrome mice is restored by resveratrol

Patients with Marfan syndrome (MFS) develop thoracic aortic aneurysms as the aorta presents excessive elastin breaks, fibrosis, and vascular smooth muscle cell (vSMC) death due to mutations in the FBN1 gene. Despite elaborate vSMC to aortic endothelial cell (EC) signaling, the contribution of ECs to the development of aortic pathology remains largely unresolved. The aim of this study is to investigate the EC properties in Fbn1C1041G/+ MFS mice. Using en face immunofluorescence confocal microscopy, we showed that EC alignment with blood flow was reduced, EC roundness was increased, individual EC surface area was larger, and EC junctional linearity was decreased in aortae of Fbn1C1041G/+ MFS mice. This modified EC phenotype was most prominent in the ascending aorta and occurred before aortic dilatation. To reverse EC morphology, we performed treatment with resveratrol. This restored EC blood flow alignment, junctional linearity, phospho-eNOS expression, and improved the structural integrity of the internal elastic lamina of Fbn1C1041G/+ mice. In conclusion, these experiments identify the involvement of ECs and underlying internal elastic lamina in MFS aortic pathology, which could act as potential target for future MFS pharmacotherapies.

Short-term rapamycin treatment increases life span and attenuates aortic aneurysm in a murine model of Marfan-Syndrome

BACKGROUND

Marfan syndrome (MFS) is a genetic disorder leading to medial aortic degeneration and life-limiting dissections. To date, there is no causal prevention or therapy. Rapamycin is a potent and selective inhibitor of the mechanistic target of rapamycin (mTOR) protein kinase, regulating cell growth and metabolism. The mgR/mgR mice represent an accepted MFS model for studying aortic pathologies to understand the underlying molecular pathomechanisms. This study investigated whether rapamycin inhibits the development of thoracic aortic aneurysms and dissections in mgR/mgR mice.

METHODS

Isolated primary aortic smooth muscle cells (mAoSMCs) from mgR/mgR mice were used for in vitro studies. Two mg kg/BW rapamycin was injected intraperitoneally daily for two weeks, beginning at 7-8 weeks of age. Mice were sacrificed 30 days post-treatment. Histopathological and immunofluorescence analyses were performed using adequate tissue specimens and techniques. Animal survival was evaluated accompanied by periodic echocardiographic examinations of the aorta.

RESULTS

The protein level of the phosphorylated ribosomal protein S6 (p-RPS6), a downstream target of mTOR, was significantly increased in the aortic tissue of mgR/mgR mice. In mAoSMCs isolated from these animals, expression of mTOR, p-RPS6, tumour necrosis factor α, matrix metalloproteinase-2 and -9 was significantly suppressed by rapamycin, demonstrating its anti-inflammatory capacity. Short-term rapamycin treatment of Marfan mice was associated with delayed aneurysm formation, medial aortic elastolysis and improved survival.

CONCLUSIONS

Short-term rapamycin-mediated mTOR inhibition significantly reduces aortic aneurysm formation and thus increases survival in mgR/mgR mice. Our results may offer the first causal treatment option to prevent aortic complications in MFS patients.

Pre-implantation genetic testing for Marfan syndrome using mini-sequencing

Marfan syndrome (MFS1) is an autosomal dominant condition causing aortopathy including fatal aortic dissection. This study aimed to perform clinical PGT-M in a family with a history of MFS1 for two generations. A family with two members affected by MFS1 approached the hospital for PGT-M. The couple decided to join the project following extensive counselling and informed consent was obtained. The mutation contributory to MFS1 was identified using whole-exome sequencing (WES). A novel PGT-M protocol using multiplex fluorescent PCR and mini-sequencing was developed and tested. Ten blastocysts were subjected to PGT-M in two clinical PGT cycles. Mini-sequencing revealed four normal and six affected embryos. Microsatellite-based linkage analysis confirmed mutation analysis results in all samples. The embryos diagnosed as normal (non-MFS1) were chosen for transfer. A pregnancy was obtained in the third embryo transfer. Invasive prenatal diagnosis confirmed the normal genotype of the baby. This study demonstrated comprehensive management using the application of clinical-based diagnosis, WES for mutation identification within the MFS1 gene, mini-sequencing for embryo selection and microsatellite-based linkage analysis for backup of PGT-M results and contamination detection to assist couples in having a healthy child when there was a family history of Marfan syndrome.Impact StatementWhat is already known on this subject? Marfan syndrome (MFS1, OMIM#154700) is an autosomal dominant condition causing aortopathy including fatal aortic dissection. Pre-implantation genetic testing (PGT) is an alternative to traditional invasive prenatal diagnosis (PND) giving the couples the chance of starting pregnancy with the confidence that the baby will be unaffected. Most of the previous PGT reports employed microsatellite-based linkage analysis. A few PGT studies used sequencing, mini-sequencing and mutation analysis; however, the details of the techniques were not described.What do the results of this study add? Single-cell PCR protocol using multiplex fluorescent PCR and mini-sequencing was developed and validated. Two clinical PGTs cycles for Marfan syndrome were performed. A healthy baby was resulted. The details of multiplex fluorescent PCR and mini-sequencing protocols are described in this study so that the procedures can be reproduced.What are the implications of these findings for clinical practice and/or further research? Embryo selection can help the family suffering from Marfan syndrome for two generations to start a pregnancy with confidence that their child will be unaffected. This study also shows the use of a mini-sequencing protocol for PGT, which can be a universal protocol for other mutations by changing the PCR primers and mini-sequencing primers.

Cardiac Complications in Marfan Syndrome: A Review

Marfan syndrome (MFS) is a rare inherited disorder of the connective tissue with an autosomal dominant mode of inheritance which happens as a result of a mutation in the fibrillin-1 (FBN1) gene located on chromosome 15q21.1. This mutation results in the defective formation of microfibrils and increased levels of active transforming growth factor beta (TGF beta), leading to defective connective tissue synthesis. These changes affect various parts of the body but most notably affected are the heart, eyes, and the musculoskeletal system. The standard presenting features of a person suffering from MFS are tall stature with a large arm span, kyphosis, congenital dislocation of the lens (ectopia lentis) and cardiovascular manifestations. The 2010 modified Ghent criteria are used to diagnose MFS on the basis of parameters such as cardiovascular, eye, and musculoskeletal disorders. The cardiovascular manifestations in a patient with MFS are the leading causes of mortality. The most common and dreaded complication is an aortic aneurysm and subsequent dissection. Cardiomyopathy and arrhythmia are also potential killers in such patients. This article aims to look at the various cardiac complications mentioned above and gain an understanding of their pathogenesis, incidence, and outcome. It also includes a brief overview of the rare complication post-Bentall graft infection, and its cause, diagnosis, and management. Various articles by several different authors from around the world were searched for information regarding the pathogenesis, incidence, and outcomes of these patients and are referenced below.

Fibrillin-1 Regulates Arteriole Integrity in the Retina

Fibrillin-1 is an extracellular matrix protein that assembles into microfibrils that provide critical functions in large blood vessels and other tissues. Mutations in the fibrillin-1 gene are associated with cardiovascular, ocular, and skeletal abnormalities in Marfan syndrome. Fibrillin-1 is a component of the wall of large arteries but has been poorly described in other vessels. We examined the microvasculature in the retina using wild type mice and two models of Marfan syndrome, Fbn1^C1041G/+ and Fbn1^mgR/mgR. In the mouse retina, fibrillin-1 was detected around arterioles, in close contact with the basement membrane, where it colocalized with MAGP1. Both a mutation in fibrillin-1 or fibrillin-1 underexpression characteristically altered the microvasculature. In Fbn1^C1041G/+ and Fbn1^mgR/mgR mice, arterioles were enlarged with reduced MAGP1 deposition and focal loss of smooth muscle cell coverage. Losartan, which prevents aortic enlargement in Fbn1^C1041G/+ mice, prevented smooth muscle cell loss and vessel leakiness when administrated in a preventive mode. Moreover, losartan also partially rescued the defects in a curative mode. Thus, fibrillin-1/MAGP1 performs essential functions in arteriolar integrity and mutant fibrillin-1-induced defects can be prevented or partially rescued pharmacologically. These new findings could have implications for people with Marfan syndrome.

Case Report: A Novel Homozygous Missense Variant of FBN3 Supporting It Is a New Candidate Gene Causative of a Bardet–Biedl Syndrome–Like Phenotype

Fibrillin proteins are extracellular matrix glycoproteins assembling into microfibrils. FBN1, FBN2, and FBN3 encode the human fibrillins and mutations in FBN1 and FBN2 cause connective tissue disorders called fibrillinopathies, affecting cardiovascular, dermal, skeletal, and ocular tissues. Recently, mutations of the less characterized fibrillin family member, FBN3, have been associated in a single family with Bardet–Biedl syndrome (BBS). Here, we report on a patient born from two first cousins and affected by developmental delay, cognitive impairment, obesity, dental and genital anomalies, and brachydactyly/syndactyly. His phenotype was very similar to that reported in the previous FBN3-mutated family and fulfilled BBS clinical diagnostic criteria, although lacking polydactyly, the most recurrent clinical feature, as the previous siblings described. A familial SNP-array and proband’s WES were performed prioritizing candidate variants on the sole patient’s runs of homozygosity. This analysis disclosed a novel homozygous missense variant in FBN3 (NM_032447:c.5434A>G; NP_115823:p.Ile1812Val; rs115948457), inherited from the heterozygous parents. This study further supports that FBN3 is a candidate gene for a BBS-like syndrome characterized by developmental delay, cognitive impairment, obesity, dental, genital, and skeletal anomalies. Anyway, additional studies are necessary to investigate the exact role of the gene and possible interactions between FBN3 and BBS proteins.

Male Marfan mice are predisposed to high fat diet induced obesity, diabetes, and fatty liver

Gene mutations in the extracellular matrix protein fibrillin-1 cause connective tissue disorders including Marfan syndrome (MFS) with clinical symptoms in the cardiovascular, skeletal, and ocular systems. MFS patients also exhibit alterations in adipose tissues, which in some individuals leads to lipodystrophy, whereas in others to obesity. We have recently demonstrated that fibrillin-1 regulates adipose tissue homeostasis. Here, we examined how fibrillin-1 abnormality affects metabolic adaptation to different diets. We used two MFS mouse models: Hypomorph Fbn1^mgR/mgR mice and Fbn1^C1041G/+ mice with a fibrillin-1 missense mutation. When Fbn1^mgR/mgR mice were fed with high fat diet (HFD) for 12 weeks, male mice were heavier than littermate controls (LC), whereas female mice gained less weight compared to LC. Female Fbn1^C1041G/+ mice on a HFD for 24 weeks were similarly protected from weight gain. Male Fbn1^C1041G/+ mice on HFD demonstrated higher insulin levels, insulin intolerance, circulating levels of cholesterol and high-density lipoproteins. Moreover, male HFD-fed Fbn1^C1041G/+ mice showed a higher liver weight and a fatty liver phenotype, which was reduced to LC levels after orchiectomy. Phosphorylation of protein kinase-like endoplasmic reticulum kinase (PERK) as well as the expression of sterol regulatory element-binding protein 1 (Srebp1) in livers of HFD-fed male Fbn1^C1041G/+ mice were elevated. In conclusion, the data demonstrate that male mice of both MFS models are susceptible to HFD-induced obesity and diabetes. Moreover, male Fbn1^C1041G/+ mice develop a fatty liver phenotype, likely mediated by a baseline increased endoplasmic reticulum stress. In contrast, female MFS mice were protected from the consequence of HFD.