A Novel Heterozygous Intronic FBN1 Variant Contributes to Aberrant RNA Splicing in Marfan Syndrome.

BACKGROUND: Marfan syndrome (MFS) is a complex genetic systemic connective tissue disorder. It is well known that genetic factors play a critical role in the progression of MFS, with nearly all cases attributed to variants in the FBN1 gene. METHODS: We investigated a Chinese family with MFS spanning two generations. Whole exome sequencing, in silico analysis, minigene constructs, transfection, RT-PCR, and protein secondary structure analysis were used to analyze the genotype of the proband and his father. RESULTS: The main clinical manifestations of the proband and his father were subluxation of the left lens and high myopia with pectus deformity. Whole exome sequencing identified a novel single nucleotide variant (SNV) in the FBN1 gene at a non-canonical splice site, c.443-3C>G. This variant resulted in two abnormal mRNA transcripts, leading to a frameshift and an in-frame insertion. Further in vitro experiments indicated that the c.443-3C>G variant in FBN1 was pathogenic and functionally harmful. CONCLUSION: This research identified a novel intronic pathogenic FBN1: c.443-3C>G gene variant, which led to two different aberrant splicing effects. Further functional analysis expands the variant spectrum and provides a strong indication and sufficient basis for preimplantation genetic testing for monogenic disease (PGT-M).

Cerebral hypoperfusion resulting from improper cannulation positioning during aortic dissection surgery: a case report.

BACKGROUND: Selective antegrade cerebral perfusion (sACP) is a crucial cerebral protection technique employed during aortic dissection surgeries involving cardiopulmonary bypass. However, postoperative neurological complications, particularly those related to cannulation issues and perfusion problems, remain a significant concern. CASE PRESENTATION: This case report details an unusual instance where a 38-year-old male patient with Marfan syndrome experienced cerebral hypoperfusion during emergency surgery for Stanford Type A aortic dissection. Despite following standard protocols, a significant drop in regional cerebral oxygen saturation (rSO2) and abnormal blood pressure fluctuations were observed shortly after initiating sACP via the innominate artery. After initial attempts to optimize perfusion flow proved ineffective, the cannulation position was adjusted, leading to improvements. Nevertheless, the patient subsequently exhibited signs of cerebral hypoperfusion and was found to have suffered a new cerebral infarction. CONCLUSIONS: This case report underscores the importance of precise cannula placement during sACP procedures and the dire consequences that can arise from improper positioning. It emphasizes the need for continuous monitoring and prompt intervention in cases of abnormal cerebral oxygenation and blood pressure, as well as the value of considering cannulation-related issues as potential causes of postoperative neurological complications.

Musculoskeletal Issues in Children and Adolescents: Genetic Musculoskeletal Disorders.

Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder with progressive proximal weakness as the principal sign. Glucocorticoids and physical therapy are the mainstay of treatment. Exercise intolerance is the hallmark of metabolic myopathies, which require a combination of laboratory testing, electrodiagnostic testing, and muscle biopsy for diagnosis. Joint hypermobility may be an isolated finding or be associated with hypermobility Ehlers-Danlos syndrome (EDS), other variants of EDS, or marfanoid syndromes. The latter conditions are associated with aortic and cardiac valvular abnormalities. Osteogenesis imperfecta encompasses a group of disorders characterized by bone fragility presenting with a low-impact fracture as a result of minimal trauma. Management includes multidiscipline specialists. Down syndrome (DS), or trisomy 21, is the most common chromosome abnormality identified in live births. Routine evaluation of atlantoaxial instability with x-ray is no longer recommended for children with DS without symptoms of atlantoaxial instability; however, clinical evaluation of symptoms is required for sports preparticipation. Achondroplasia is the most common skeletal dysplasia. Clinical signs are macrocephaly, short limb, short stature with disproportionately shorter humerus and femur, along with characteristic findings in pelvis and lumbar spine x-rays. Caregivers should be educated on proper positioning and handling to avoid complications, including car seat-related deaths.

Minimally invasive valve-sparing aortic root replacement via an upper mini-sternotomy in a young adult with Marfan syndrome.

We describe an upper mini-sternotomy for valve-sparing aortic root replacement in a teenager.

The Contribution of Mast Cells to the Regulation of Elastic Fiber Tensometry in the Skin Dermis of Children with Marfan Syndrome.

Marfan syndrome (MFS) is a hereditary condition accompanied by disorders in the structural and regulatory properties of connective tissue, including elastic fibers, due to a mutation in the gene encodes for fibrillin-1 protein (FBN1 gene) and the synthesis of abnormal fibrillin-1 glycoprotein. Despite the high potential of mast cells (MCs) to remodel the extracellular matrix (ECM), their pathogenetic significance in MFS has not been considered yet. The group of patients with Marfan syndrome included two mothers and five children (three girls aged 4, 11, and 11 and two boys aged 12 and 13). Normal skin was examined in two children aged 11 and 12. Histochemical, monoplex, and multiplex immunohistochemical techniques; combined protocols of simultaneous histochemical and immunohistochemical staining (the results of staining were assessed using light, epifluorescence, and confocal microscopy); and bioinformatics algorithms for the quantitative analysis of detected targets were used to evaluate mast cells and their relationship with other cells from extracellular structures in the skin dermis. Analysis of the skin MC population in children with Marfan syndrome revealed a considerably increased number of intra-organic populations with the preservation of the specific Tryptase+Chymase+CPA3+ protease profile typical of the skin. The features of the MC histotopography phenotype in MFS consisted of closer colocalization with elastic fibers, smooth muscle cells, and fibroblasts. MCs formed many intradermal clusters that synchronized the activity of cell functions in the stromal landscape of the tissue microenvironment with the help of spatial architectonics, including the formation of cell chains and the creation of fibrous niches. In MCs, the expression of specific proteases, TGF-ß, and heparin increased, with targeted secretion of biologically active substances relative to the dermal elastic fibers, which had specific structural features in MFS, including abnormal variability in thickness along their entire length, alternating thickened and thinned areas, and uneven surface topography. This paper discusses the potential role of MCs in strain analysis (tensometry) of the tissue microenvironment in MFS. Thus, the quantitative and qualitative rearrangements of the skin MC population in MFS are aimed at altering the stromal landscape of the connective tissue. The results obtained should be taken into account when managing clinical signs of MFS manifested in other pathogenetically critical structures of internal organs, including the aorta, tendons, cartilage, and parenchymal organs.

Neonatal Marfan syndrome: a case report of a novel fibrillin 1 mutation, with genotype-phenotype correlation and brief review of the literature.

BACKGROUND: Neonatal Marfan syndrome (nMFS) is a rare condition characterized by severe phenotype and poor prognosis. nMFS is caused by mutations in a specific region of the fibrillin 1 gene (FBN1). Prompt recognition of typical signs of neonatal presentation, such as characteristic facial anomalies with senile appearance, arthrogryposis, and campto-arachnodactyly, is fundamental for performing an early cardiological examination. This usually reveals rapidly progressive cardiovascular disease due to severe atrioventricular valve dysfunction. CASE PRESENTATION: Herein, we report the case of an early-onset cardiac failure in a neonate with Marfan syndrome, with a brief review of the literature of cases with cardiac involvement in neonatal age. Clinical exome sequencing identified the novel heterozygous de novo missense variant c.3152T > G in FBN1 gene (NM_000138.4), causing the aminoacidic change p.Phe1051Cys. Phenotype-genotype correlation led to a multidisciplinary diagnostic and management workflow. CONCLUSION: The prompt recognition of a typical phenotype such as that of Marfan syndrome should lead to a detailed evaluation and close follow-up of cardiac morphology and function. Indeed, multi-disciplinary evaluation based on genotype-phenotype correlations of nMFS cases is essential to finding out the best medical and surgical approach, predicting the relevant impact on patient prognosis, and adequately counseling their families.

Complement C3a/C3aR inhibition alleviates the formation of aortic aneurysm in Marfan syndrome mice.

Mutations in fibrillin 1 (FBN1) is the main cause of Marfan syndrome (MFS) with thoracic aortic aneurysm (TAA) as the main complication. Activation of the complement system plays a key role in the formation of thoracic and abdominal aortic aneurysms. However, the role of the complement system in MFS-associated aortic aneurysms remains unclear. In this study, we observed increased levels of complement C3a and C5a in the plasma of MFS patients and mouse, and the increased deposition of the activated complement system product C3b/iC3b was also observed in the elastic fiber rupture zone of 3-month-old MFS mice. The expression of C3a receptor (C3aR) was increased in MFS aortas, and recombinant C3a promoted the expression of cytokines in macrophages. The administration of a C3aR antagonist (C3aRA) attenuated the development of thoracic aortic aneurysms in MFS mice. The increased inflammation response and matrix metalloproteinases activities were also attenuated by C3aRA treatment in MFS mice. Therefore, these findings indicate that the complement C3a/C3aR inhibition alleviates the formation of aortic aneurysm in Marfan syndrome mice.

Pituitary pseudo-adenoma from cerebrospinal fluid leak in patient with Marfan syndrome.

Intracranial hypotension may result in pituitary gland enlargement due to compensatory hyperaemia and venous engorgement. Spontaneous intracranial hypotension (SIH) is frequently associated with connective tissue disorders predisposing patients to dural weakening including dural ectasia and meningeal diverticula. Symptoms of SIH typically include postural headache, dizziness and tinnitus. We present a case of a female in her 20s with Marfan syndrome and a history of pituitary adenoma, who reported intractable postural headaches. Hormonal workup revealed no abnormalities, whereas brain MRI showed sequelae of intracranial hypotension. Further MRI studies revealed thoracic and lumbar meningeal diverticula with significant dural sac ectasia at the L4-S2 level. Myelogram confirmed numerous lumbar spine diverticula with cerebrospinal fluid leak at the L5 and S1 right nerve roots. The patient underwent blood patch administrations at the level of the leak with improvement of symptoms.

Generation of Marfan syndrome-specific induced pluripotent stem cells harboring FBN1 mutations.

Marfan syndrome (MFS) is a hereditary condition caused by mutations in the FBN1 gene. Genetic mutations in the FBN1 locus impact the function of the encoded protein, Fibrillin 1, a structural molecule forming microfibrils found in the connective tissue. MFS patients develop severe cardiovascular complications including thoracic aortic aneurysm and aortic dissection, which predispose them to an enhanced risk of premature death. Here, we generated two induced pluripotent stem cell (iPSC) lines harboring mutations in the FBN1 gene (p.C1942C>A and c.1954 T>C), directly derived from MFS patients. We have shown that both iPSC lines displayed expression of pluripotency markers, normal karyotype and ability of trilineage differentiation, representing a valuable tool for the identification of new therapeutic strategies for intervening in this disease.

miRNA-Driven Regulation of Endothelial-to-Mesenchymal Transition Differs among Thoracic Aortic Aneurysms.

Thoracic aortic aneurysms (TAAs) represent a serious health concern, as they are associated with early aortic dissection and rupture. TAA formation is triggered by genetic conditions, in particular Marfan syndrome (MFS) and bicuspid aortic valve (BAV). During the aneurysmatic process, aortic endothelial cells can undergo endothelial-to-mesenchymal transition (End-MT) with consequent phenotypic and functional alterations. We previously documented that MFS TAA is characterized by miR-632-driven End-MT exacerbation, whereas in BAV aortopathy, the occurrence of this process remains still controversial. We investigated the End-MT process and the underlined regulatory mechanisms in BAV, TAV and MFS TAA tissues. Gene expression and immunohistochemical analysis were performed in order to analyze some important miRNAs and genes characterizing End-MT. We documented that BAV endothelium maintains the expression of the endothelial homeostasis markers, such as ERG, CD31 and miR-126-5p, while it shows lower levels of miR-632 and mesenchymal markers compared with MFS. Interestingly, we also found higher levels of miR-632 in MFS patients' blood. Our findings definitively demonstrate that the End-MT process does not characterize BAV that, among the other TAAs, better maintains the endothelial features. In addition, our results suggest miR-632 as a promising diagnostic/prognostic factor in MFS aortopathy.

Right ventricular function in Marfan patients remains stable despite multiple cardiac interventions.

OBJECTIVES: Mitral valve regurgitation and left ventricular dysfunction are cardiovascular symptoms of Marfan syndrome. There is a paucity of information on tricuspid valve regurgitation and right ventricular function. In patients with Marfan syndrome, we looked at long-term changes in right ventricular function, tricuspid valve regurgitation and freedom from tricuspid valve repair. METHODS: Retrospective-observational single-centre analysis on right ventricular function and tricuspid regurgitation in Marfan patients who underwent surgery with cardioplegic arrest between 1995 and 2020. Patients were followed-up from 1st operation until death, with echocardiographic changes analysed longitudinally. Composite end point was tricuspid annular plane systolic excursion (TAPSE) ≤16 mm, severe tricuspid regurgitation or tricuspid repair. RESULTS: The study included 135 patients who underwent 193 operations, 58 of those were reoperations in 40 patients. Median age at 1st operation was 35 years [interquartile range (IQR) 26-46], median follow-up was 8.0 years (IQR 3.0-16.0) and median time to 1st reoperation was 7.5 years (IQR 3.4-12.5). The composite end point occurred in 81 observations in 40 patients, mostly as a recurrent event, after median 7.0 years (IQR 1.0-13.0). Ten-year cumulative incidence for composite end point was 22.0% (95% CI 15-31) and 9.0% (95% CI 4.4-16) for new-onset TAPSE ≤16 mm, but no significant change in TAPSE was observed at 10 years. Tricuspid regurgitation was associated with increased risk of annual progression (P < 0.001), but not clinically relevant at 10 years. Actuarial 10-year survival was 91.1%. CONCLUSIONS: In Marfan patients with a history of cardiac surgery and subsequent reoperations, the right ventricular function remains stable. The incidence of severe tricuspid regurgitation and tricuspid repair remain low.

Serous-Exudative Detachment and Progressive Macular Degeneration in a Patient With Kabuki and Marfan Syndrome.

To our knowledge, this is the first report of a patient with both genetically confirmed Kabuki and Marfan syndrome demonstrating a perifoveal macular degeneration in one eye. Progressive loss of the outer retinal layers was captured and demonstrated with spectral-domain optical coherence tomography imaging. Fundus autofluorescence imaging revealed perifoveal hypoautofluorescence. The patient had initially presented with a spontaneously resolved serous-exudative retinal detachment associated with tortuous retinal vasculature and preretinal proliferative vitreoretinopathy in the other eye. Prior to presentation, the patient had an ocular history of bilateral ectopia lentis treated with crystalline lens removal and placement of iris-claw intraocular lenses. [Ophthalmic Surg Lasers Imaging Retina 2024;55:541-544.].

A case of large aneurysms of the coronary arteries and abdominal aorta in an infant.

Aneurysms of the coronary arteries and abdominal aorta are extremely rare in infancy. Due to the rarity of the anomaly, there are no existing guidelines on management of these aneurysms. We describe the challenges in diagnosis, evaluation and management of an infantile Marfan with this rare presentation.

Visual Outcomes in Ectopia Lentis in Marfan Syndrome: A Study of Four Surgical Techniques in Children and Adults.

Background/Objectives: To evaluate how the surgical technique and type of implanted intraocular lens influence the postoperative visual acuity and complications in ectopia lentis associated to Marfan syndrome patients. Materials and Methods: The medical records and videos of ectopia lentis surgeries in patients (children and adults) with Marfan syndrome, were retrospectively reviewed and compared. The study included 33 eyes that underwent four different intraocular lens implantation (IOL) techniques: IOL in conjunction with a simple capsular tension ring, IOL in conjunction with a Cionni modified capsular tension ring (m-CTR), two-point scleral IOL fixation and IOL with one haptic in the bag and one haptic sutured to the sclera. Results: Vision significantly improved from a mean preoperative visual acuity of 0.1122 to a mean postoperative visual acuity of 0.4539 in both age groups (p < 0.0001), with no difference in the primary outcome between children and adults. The most common surgical technique used in both age groups was IOL in conjunction with an m-CTR. There was only one major postoperative complication requiring additional surgery. Conclusions: Zonular weakness mainly influenced by age was the most important selection criterion for the surgical approach. Regardless of the technique employed, the postoperative visual acuity was improved in both adults and children.

[Correlation of posterior segment lesions with anterior segment biometric parameters and FBN1 genotype in patients with Marfan syndrome].

Objective: To investigate the characteristics of posterior segment lesions in Marfan syndrome (MFS) patients and their relationship with anterior segment biometric parameters and FBN1 genotype. Methods: A cross-sectional study was conducted. A total of 121 MFS patients, 76 males and 45 females, with an average age of (11.72±11.66) years, who visited the Department of Ophthalmology, Eye & ENT Hospital of Fudan University from January 2013 to March 2023 were included. The presence of posterior scleral staphyloma was observed using B-mode ultrasound, and macular lesions were identified and classified using the atrophy-traction-neovascularization system based on ultra-widefield fundus images, color fundus images, and optical coherence tomography scans. Anterior segment biometric parameters, including axial length of the eye, average corneal curvature, corneal astigmatism, horizontal corneal diameter, anterior chamber depth, and lens thickness, were collected, and the direction and extent of lens dislocation were observed. Molecular genetic analysis of FBN1 gene mutations in patients was performed using next-generation sequencing based on a panel of ocular genetic diseases, and the impact of the genotype and anterior segment biometric parameters on the posterior segment manifestations was analyzed. Results: Sixty patients exhibited posterior segment lesions, including retinal detachment (4 cases, 3.31%), macular lesions (47 cases, 38.84%), and posterior scleral staphyloma (54 cases, 44.63%). There was statistically significant difference in axial length of the eye between patients with and without posterior scleral staphyloma [23.09 (22.24, 24.43) and 27.04 (25.44, 28.88) mm], between patients with and without macular lesions [23.16 (22.24, 24.61) and 27.04 (25.74, 28.78) mm], and between patients with and without atrophic macular lesions [23.16 (22.24, 24.61) and 27.04 (25.74, 28.79) mm] (all P<0.001). There was statistically significant difference in anterior chamber depth between patients with and without macular lesions [3.11 (2.75, 3.30) and 3.34 (3.09, 3.60) mm] (P<0.05). There was also statistically significant difference in corneal astigmatism between patients with and without posterior scleral staphyloma [2.15 (1.20, 2.93) and 1.40 (1.00, 2.20) diopters] (P<0.05). The location and region of the FBN1 gene mutation not only showed statistically significant difference from the positive rates of posterior scleral staphyloma and macular lesions (all P<0.05), but also influenced the occurrence of atrophic macular lesions (both P<0.05). Patients with FBN1 mutations located in the transforming growth factor ß regulatory sequence had the highest proportion of posterior scleral staphyloma and macular lesions (both 10/11). Conclusions: Posterior scleral staphyloma and macular lesions have a relatively high incidence in MFS patients and tend to progress to more severe grades. The age, axial length of the eye, anterior chamber depth, corneal astigmatism, and location and region of the FBN1 gene mutation are factors affecting the posterior segment lesions in MFS patients.

Coding and Non-Coding Transcriptomic Landscape of Aortic Complications in Marfan Syndrome.

Marfan syndrome (MFS) is a rare congenital disorder of the connective tissue, leading to thoracic aortic aneurysms (TAA) and dissection, among other complications. Currently, the most efficient strategy to prevent life-threatening dissection is preventive surgery. Periodic imaging applying complex techniques is required to monitor TAA progression and to guide the timing of surgical intervention. Thus, there is an acute demand for non-invasive biomarkers for diagnosis and prognosis, as well as for innovative therapeutic targets of MFS. Unraveling the intricate pathomolecular mechanisms underlying the syndrome is vital to address these needs. High-throughput platforms are particularly well-suited for this purpose, as they enable the integration of different datasets, such as transcriptomic and epigenetic profiles. In this narrative review, we summarize relevant studies investigating changes in both the coding and non-coding transcriptome and epigenome in MFS-induced TAA. The collective findings highlight the implicated pathways, such as TGF-ß signaling, extracellular matrix structure, inflammation, and mitochondrial dysfunction. Potential candidates as biomarkers, such as miR-200c, as well as therapeutic targets emerged, like Tfam, associated with mitochondrial respiration, or miR-632, stimulating endothelial-to-mesenchymal transition. While these discoveries are promising, rigorous and extensive validation in large patient cohorts is indispensable to confirm their clinical relevance and therapeutic potential.

Response to the Letter regarding "The usefulness of the genetic panel in the classification and refinement of diagnostic accuracy of Mexican patients with Marfan syndrome and other connective tissue disorders".

Dear Editor, In relation to the letter expressing concerns about some important points of the article entitled "The usefulness of the genetic panel in the classification and refinement of diagnostic accuracy of Mexican patients with Marfan syndrome and other connective tissue disorders", we would like to comment on the following.  Read more in the PDF.

Targeted next-generation sequencing reveals the genetic mechanism of Chinese Marfan syndrome cohort with ocular manifestation.

BACKGROUND: Marfan syndrome (MFS) is a hereditary connective tissue disorder involving multiple systems, including ophthalmologic abnormalities. Most cases are due to heterozygous mutations in the fibrillin-1 gene (FBN1). Other associated genes include LTBP2, MYH11, MYLK, and SLC2A10. There is significant clinical overlap between MFS and other Marfan-like disorders. PURPOSE: To expand the mutation spectrum of FBN1 gene and validate the pathogenicity of Marfan-related genes in patients with MFS and ocular manifestations. METHODS: We recruited 318 participants (195 cases, 123 controls), including 59 sporadic cases and 88 families. All patients had comprehensive ophthalmic examinations showing ocular features of MFS and met Ghent criteria. Additionally, 754 cases with other eye diseases were recruited. Panel-based next-generation sequencing (NGS) screened mutations in 792 genes related to inherited eye diseases. RESULTS: We detected 181 mutations with an 84.7% detection rate in sporadic cases and 87.5% in familial cases. The overall detection rate was 86.4%, with FBN1 accounting for 74.8%. In cases without FBN1 mutations, 23 mutations from seven Marfan-related genes were identified, including four pathogenic or likely pathogenic mutations in LTBP2. The 181 mutations included 165 missenses, 10 splicings, three frameshifts, and three nonsenses. FBN1 accounted for 53.0% of mutations. The most prevalent pathogenic mutation was FBN1 c.4096G>A. Additionally, 94 novel mutations were detected, with 13 de novo mutations in 14 families. CONCLUSION: We expanded the mutation spectrum of the FBN1 gene and provided evidence for the pathogenicity of other Marfan-related genes. Variants in LTBP2 may contribute to the ocular manifestations in MFS, underscoring its role in phenotypic diversity.

Self-care behaviors and their individual-level determinants in Italian adults with Marfan syndrome: A single-center cross-sectional study.

AIM: This study aimed to describe the levels of self-care behaviors and self-care self-efficacy in patients with Marfan syndrome and to identify the individual-level determinants of self-care behaviors. BACKGROUND: The behaviors aimed at maintaining health stability (self-care maintenance), monitoring signs and symptoms (self-care monitoring), and taking action when signs and symptoms occur (self-care management) are key aspects of the care for addressing the complexity of care of patients with Marfan syndrome. However, the description of self-care behaviors and their determinants in patients with Marfan syndrome are highly under-described. METHODS: The adopted design was descriptive observational with a cross-sectional data collection on 111 patients with MFS in a single Italian specialized and reference center for this disease between 2020 and 2021. RESULTS: Performing healthy activities and managing illness, therapies, and follow-ups to maintain health over time (self-care maintenance) was almost adequate (mean score = 67.87 ± 13.17), as well as the ability to recognize signs and symptoms promptly (self-care monitoring, mean score = 67.95 ± 26.70). The ability to respond to symptoms when they occur (self-care management, mean score = 54.17 ± 19.94) was sub-optimal. The stronger positive predictor of each self-care behavior was self-care self-efficacy. CONCLUSIONS: This study suggested prioritizing educational activities focused on enhancing self-care management in patients with Marfan syndrome and strengthening their self-care self-efficacy. Researchers should develop and validate evidence-based educational approaches to enhance self-care in patients with Marfan syndrome, and clinical nurses should strengthen their focused educational activities to improve the self-care management of these patients.