Reclassification of an FBN1 variant emphasizes the importance of segregation analysis, information sharing, and multidisciplinary teamwork in understanding genetic variants in health and disease.

Marfan syndrome (MFS) is a complex connective tissue disorder characterized by considerable clinical variability. The diagnosis of MFS is based on the Ghent criteria, which require the presence of both clinical and genetic features. MFS is primarily caused by pathogenic alterations in FBN1, which encodes the fibrillin-1 protein. Fibrillin-1 comprises multiple domains rich in cysteine residues, with disulfide bonds formed between these residues. It has long been recognized that variants that alter or introduce cysteine residues damage protein function, leading to the development of MFS. In this study, we report a cysteine-introducing variant: FBN1 variant, c.6724C>T (p.[Arg2242Cys]). We have observed this variant in several individuals without MFS, challenging our previous understanding of the underlying mechanism of MFS. This finding emphasizes the importance of revisiting and reevaluating our current knowledge in light of new and unexpected observations. Moreover, our study highlights the significance of incorporating local and national data on allele frequencies, as well as employing multidisciplinary phenotyping approaches, in the classification of genetic variants. By considering a wide range of information, we can enhance the accuracy and reliability of variant classification, ultimately improving the diagnosis and management of individuals with genetic disorders like MFS.

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.

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.

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.].

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.

Anterior scleral thickness in Marfan syndrome: A quantitative analysis.

PURPOSE: To investigate the anterior scleral thickness (AST) in patients with Marfan syndrome (MFS). METHODS: A prospective, cross-sectional study was conducted at the Department of Ophthalmology, Ghent University Hospital, Ghent, including patients with a genetically confirmed clinical diagnosis of MFS and age-, gender- and axial length-matched controls. Subjects with known corneal, conjunctival or scleral pathology and a history of ocular surgery, including pars plana vitrectomy, recent contact lens use or high-grade astigmatism were excluded. Subjects underwent non-cycloplegic autorefraction, Scheimpflug-based corneal tomography, axial length measurement and spectral-domain optical coherence tomography (OCT). AST was manually measured at 1 mm (AST1), 2 mm (AST2) and 3 mm (AST3) from the scleral spur, temporally and nasally. RESULTS: A total of 56 subjects (28 subjects in the MFS group and 28 matched subjects in the control group) were included in this study. In patients with MFS, AST was significantly reduced compared to matched controls, both overall and at every analysed measuring point in the nasal and temporal areas (p < 0.001). Central corneal thickness (CCT) and mean keratometry (Kmean) values were significantly lower in patients with MFS (p < 0.05). A positive correlation was found between nasal AST and CCT in patients with MFS. No correlation was found between AST and Kmean or between AST and axial length. In patients with MFS with ectopia lentis, compared to those without, temporal AST3 was significantly lower (p < 0.05). AST was significantly lower in patients with MFS harbouring a variant predicted to cause haploinsufficiency compared to those with a variant expected to lead to a dominant negative effect for both nasal and temporal measurements. CONCLUSION: Based on anterior segment OCT measurements, AST of patients with MFS is significantly lower compared to matched controls.

The relationship between mitral valve prolapse and thoracic skeletal abnormalities in clinical practice: a systematic review.

BACKGROUND: Literature data suggest high inter-study variability in mitral valve prolapse (MVP) prevalence among individuals with thoracic skeletal abnormalities (TSA). This systematic review aimed at estimating the overall prevalence of MVP in individuals with the most common TSA, including not only the oldest studies (before the year 2000) but also the most recent ones (after the year 2000). METHODS: PubMed and EMBASE databases were systematically reviewed in November 2023. Studies assessing the relationship between MVP and TSA and estimating the MVP prevalence in pectus excavatum (PE), pectus carinatum (PC), scoliosis, straight back syndrome (SBS) and Marfan syndrome (MS) were included. There was no limitation on time periods. RESULTS: Twenty-five studies with a total of 2800 patients (27.9 ±â€Š13.9 years, 48.2% females) were analyzed. The highest prevalence of MVP was observed among MS patients (47.3%), while the lowest was detected in PC individuals (23%). Prevalence of MVP was similar among PE (30.8%), scoliosis (26.3%) and SBS (25.5%) patients. When dividing the studies on the basis of temporal period, the average MVP prevalence was approximately two-fold higher in all studies conducted before the year 2000 in comparison with the most recent ones, regardless of TSA type. This discrepancy might be primarily ascribed to relevant differences in the echocardiographic criteria employed for MVP diagnosis before (less specific) and after (more specific) the year 2000, respectively. CONCLUSIONS: The estimated MVP prevalence in TSA individuals is significantly higher than that observed in the general population. Individuals with TSA should be screened for MVP presence on transthoracic echocardiography.

The role of genetic testing in Marfan syndrome.

PURPOSE OF REVIEW: This review aims to delineate the genetic basis of Marfan syndrome (MFS) and underscore the pivotal role of genetic testing in the diagnosis, differential diagnosis, genotype-phenotype correlations, and overall disease management. RECENT FINDINGS: The identification of pathogenic or likely pathogenic variants in the FBN1 gene, associated with specific clinical features such as aortic root dilatation or ectopia lentis, is a major diagnostic criterion for MFS. Understanding genotype-phenotype correlations is useful for determining the timing of follow-up, guiding prophylactic aortic root surgery, and providing more precise information to patients and their family members during genetic counseling. Genetic testing is also relevant in distinguishing MFS from other conditions that present with heritable thoracic aortic diseases, allowing for tailored and individualized management. SUMMARY: Genetic testing is essential in different steps of the MFS patients' clinical pathway, starting from the phase of diagnosis to management and specific treatment.

Quality of life in young patients with acute type a aortic dissection in China: comparison with Marfan syndrome and non-Marfan syndrome.

BACKGROUND: There is a paucity of Chinese studies evaluating the quality of life (QoL) in young acute type A aortic dissection (AAAD) patients with Marfan syndrome. METHODS: Young adult AAAD patients (younger than 45 years old) underwent surgical treatment at our institution from January 2017 to December 2020 were consecutive enrolled. The hospital survivors completed 1 year of follow up. Patients were divided into two groups according to the presence or absence of Marfan syndrome (MFS). A 1:1 propensity score matching (PSM) with a caliper 0.2 was conducted to balance potential bias in baseline. The follow-up data were analyzed primarily for change in quality of life and anxiety status. RESULTS: After PSM, 32 comparable pairs were matched. The baseline data were comparable and postoperative complications were similar between groups. In terms of SF-36 scale, the role physical, bodily pain, role emotional and mental health subscales were no significantly improved in MFS patients over time. At 1 year after discharged, the subscale of mental health and bodily pain were significantly lower in the MFS group than in the non-MFS group. In terms of HADS assessments, the level of anxiety in MFS patients was significantly higher than in non-MFS patients at 1 year after discharged. CONCLUSIONS: The QoL in young AAAD patients with MFS is lower than those without MFS after surgery. This may be associated with the uncontrollable persistent chronic pain and the uncertainty and concerns for the disease's progression.

Rare complications of infective endocarditis in marfan-like morphotype: diagnosis of multiple mitral valve aneurysms and aortic root abscess using three-dimensional transesophageal echocardiography.

Mitral valve aneurysm (MVA) is characterized by a saccular outpouching of the mitral leaflet, and it represents a rare condition typically associated with aortic valve endocarditis. Three-Dimensional Transesophageal Echocardiography (3D-TEE) serves as an effective tool for detecting the presence of MVA and its potential complications. In this report, we present a case involving a young man with striking images of bicuspid aortic valve endocarditis complicated by an aortic root abscess and multiple perforated mitral valve aneurysms, diagnosed using 3D TEE. This case suggests the uncommon coexistence of Marfan like morphotype, bicuspid aortic valve, and infective endocarditis as a triple mechanism in the occurrence of MVA. It underscores the significance of early and accurate imaging diagnosis for facilitating prompt surgical intervention.

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.

Marfan syndrome (MFS) is a multisystem genetic disorder with over 3000 mutations described in the fibrillin 1 (FBN1) gene. Like MFS, other connective tissue disorders also require a deeper understanding of the phenotype-genotype relationship due to the complexity of the clinical presentation, where diagnostic criteria often overlap. Our objective was to identify mutations in patients with connective tissue disorders using a genetic multipanel and to analyze the genotype-phenotype associations in a cohort of Mexican patients. We recruited 136 patients with MFS and related syndromes from the National Institute of Cardiology. Mutations were identified using next-generation sequencing (NGS). To examine the correlation between mutation severity and severe cardiovascular conditions, we focused on patients who had undergone Bentall-de Bono surgery or aortic valve repair. The genetic data obtained allowed us to reclassify the initial clinical diagnosis across various types of connective tissue disorders. The transforming growth factor beta receptor 2 (TGFBR2) rs79375991 mutation was found in 10 out of 16 (63%) Loeys-Dietz patients. We observed a high prevalence (65%) of more severe mutations, such as frameshift indels and stop codons, among patients requiring invasive treatments like aortic valve-sparing surgery, Bentall and de Bono procedures, or aortic valve replacement due to severe cardiovascular injury. Although our study did not achieve precise phenotype-genotype correlations, it underscores the importance of a multigenetic panel evaluation. This could pave the way for a more comprehensive diagnostic approach and inform medical and surgical treatment decision-making.

Re-evaluation of a Fibrillin-1 Gene Variant of Uncertain Significance Using the ClinGen Guidelines.

Background: Marfan syndrome (MFS) is caused by fibrillin-1 gene (FBN1) variants. Mutational hotspots and/or well-established critical functional domains of FBN1 include cysteine residues, calcium-binding consensus sequences, and amino acids related to interdomain packaging. Previous guidelines for variant interpretation do not reflect the features of genes or related diseases. Using the Clinical Genome Resource (ClinGen) FBN1 variant curation expert panel (VCEP), we re-evaluated FBN1 germline variants reported as variants of uncertain significance (VUSs). Methods: We re-evaluated 26 VUSs in FBN1 reported in 161 patients with MFS. We checked the variants in the Human Genome Mutation Database, ClinVar, and VarSome databases and assessed their allele frequencies using the gnomAD database. Patients' clinical information was reviewed. Results: Four missense variants affecting cysteines (c.460T>C, c.1006T>C, c.5330G>C, and c.8020T>C) were reclassified as likely pathogenic and were assigned PM1_strong or PM1. Two intronic variants were reclassified as benign by granting BA1 (stand-alone). Four missense variants were reclassified as likely benign. BP5 criteria were applied in cases with an alternate molecular basis for disease, one of which (c.7231G>A) was discovered alongside a pathogenic de novo COL3A1 variant (c.1988G>T, p.Gly633Val). Conclusions: Considering the high penetrance of FBN1 variants and clinical variability of MFS, the detection of pathogenic variants is important. The ClinGen FBN1 VCEP encompasses mutational hotspots and/or well-established critical functional domains and adjusts the criteria specifically for MFS; therefore, it is beneficial not only for identifying pathogenic FBN1 variants but also for distinguishing these variants from those that cause other connective tissue disorders with overlapping clinical features.

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.

Genotype-phenotype spectrum and prognosis of early-onset Marfan syndrome.

BACKGROUND: Marfan syndrome is a genetic connective tissue disorder affecting skeletal, ocular, and cardiovascular organ systems. Previous research found that pathogenic variants clustered in exons 24-32 of fibrillin-1 (FBN1) gene result in more severe clinical phenotypes. Furthermore, genotype-phenotype correlation studies suggested that more severe cardiovascular phenotypes were related to variants held responsible for haploinsufficiency. Our objective was to analyze the differences in clinical manifestations and genotypes of individuals with early-onset Marfan syndrome and to assess their impact on management strategies. METHODS: We analyzed clinical and genetic data of a new patient with early-onset Marfan syndrome together with 51 previously reported ones in the PubMed database between 1991 and 2022. RESULTS: Analysis showed 94% (49/52) of pathogenic variants clustered in exons 24-32 of the FBN1. The most common skeletal features were arachnodactyly (98%), reduced elbow extension (48%), pectus deformity (40%), and scoliosis (39%). Haploinsufficiency variants were reported as having poor outcome in 87.5% of the cases. Among patients carrying variants that substitute a cysteine for another amino acid and those that do not change cysteine content, cardiac intervention was found to be associated with a better outcome (p = 0.035 vs. p = 0.002). Variants that create an extra cysteine residue were found to be associated with a higher risk of ectopia lentis. Additionally, children up to 36-months-old were more often reported as still alive at the time of publication compared to newborns (p < 0.01). CONCLUSIONS: Our findings have implications for prognosis, because different genotype groups and their resulting phenotype may require personalized care and management.

[Endocapsular fixation of intraocular lens in patients with ectopia lentis and Marfan syndrome (case study)]. / Endokapsulyarnaya fiksatsiya intraokulyarnoi linzy pri ektopii khrustalika na fone sindroma Marfana (klinicheskoe nablyudenie).

Modern trends in advancement of phaco surgery techniques in patients with ectopia lentis (including patients with Marfan syndrome) are characterized by the transition from complete removal of the lens (lensectomy) to aspiration of the lens substance and attempts to preserve and reposition the capsular bag. This case study analyzes the results of surgical treatment of bilateral ectopia lentis in a 6-year-old patient with Marfan syndrome. The specifics of microinvasive phaco surgery consisted in capsular bag preservation and endocapsular fixation of the intraocular lens. The article presents the results of ophthalmological observation over a seven-year period.

[Neurological aspects of connective tissue dysplasia]. / Nevrologicheskie aspekty displazii soedinitel'noi tkani.

Disturbances in the formation of connective tissue lead to significant pathological changes in both individual organs and tissues, and at the organismal level. The complexity of diagnostics is also connected with the fact that there is no single terminology, a single view of the diagnostic criteria, a single approach among doctors of different specialties. The prevalence of external phenotypic signs of connective dysplasia is quite high, which can lead to overdiagnosis. On the other hand, insufficient attention to the manifestations of dysplasia can lead to delayed diagnosis, which can cause adverse complications. The most studied are clinical manifestations in dysplastic changes in the cardiovascular system, musculoskeletal system. This article provides an overview of current data on changes in the nervous system. Sufficient attention was paid to the pathology of the nervous system in differentiated forms (Marfan syndrome, Ehlers-Danlos, etc.). Currently, the role of various vascular anomalies, aneurysms associated with undifferentiated forms of connective tissue dysplasia is widely discussed. Much attention is also paid to clinical manifestations of the autonomic nervous system: sympathicotonic manifestations predominate in connective tissue dysplasia. There is evidence of an association of headaches, musculoskeletal pain, and connective tissue dysplasia in both children and adults.

Prevalence of intracranial aneurysms in Marfan syndrome.

OBJECTIVE: Aneurysmal pathology of the aorta is well-defined in the Marfan syndrome (MFS) population. Owing in part to the rarity of pathologies, the prevalence of intracranial aneurysms (IA) in MFS is poorly defined. There is debate as to whether or not there is an association between the two. The aim of this study was to evaluate the prevalence of IA in a population of patients with MFS who underwent intracranial imaging. METHODS: This was a single-center retrospective review of patients with MFS. Between 1995 and 2021, 983 patients were reviewed. We identified 198 patients with MFS who had intracranial imaging. Imaging consisted of CTA and/or MRA, and was read by an attending radiologist. Details of the aneurysm, patient demographics, and aortic characteristics were collected. RESULTS: The prevalence of IA was 7.1% (14/198). Age of patients with IA (55.0 ± 15.1 years) was not significantly different than those without IA (52.6 ± 16.0 years) (P = .58). The most common location of IA was the internal carotid artery. The mean diameter of the IA was 7 ± 5.8 mm. No ruptures of the internal carotid artery were identified. One patient (0.5%) underwent intervention for the IA. There were no significant differences found in aortic characteristic including dimensions, history of dissection, or aneurysm. CONCLUSIONS: In a large, single-center experience over 20 years, we identified patients with confirmed MFS who underwent intracranial imaging. The prevalence of IA in our experience was 7.1%. There were no patient or aortic characteristics found to be significantly associated with IA; however, this finding may be due to the small number of aneurysms. Although this number is higher than the historically reported prevalence in the general population, a collection of experiences from multiple institutions will likely be required to truly define the risk of IA in MFS and to determine whether screening is warranted.