Marfan's syndrome

Potential predictors of severe cardiovascular involvement in Marfan syndrome: the emphasized role of genotype-phenotype correlations in improving risk stratification-a literature review

BACKGROUND

Marfan syndrome (MFS) is a genetically determined systemic connective tissue disorder, caused by a mutation in the FBN1 gene. In MFS mainly the cardiovascular, musculoskeletal and ocular systems are affected. The most dangerous manifestation of MFS is aortic dissection, which needs to be prevented by a prophylactic aortic root replacement.

MAIN BODY

The indication criteria for the prophylactic procedure is currently based on aortic diameter, however aortic dissections below the threshold defined in the guidelines have been reported, highlighting the need for a more accurate risk stratification system to predict the occurrence of aortic complications. The aim of this review is to present the current knowledge on the possible predictors of severe cardiovascular manifestations in MFS patients, demonstrating the wide range of molecular and radiological differences between people with MFS and healthy individuals, and more importantly between MFS patients with and without advanced aortic manifestations. These differences originating from the underlying common molecular pathological processes can be assessed by laboratory (e.g. genetic testing) and imaging techniques to serve as biomarkers of severe aortic involvement. In this review we paid special attention to the rapidly expanding field of genotype-phenotype correlations for aortic features as by collecting and presenting the ever growing number of correlations, future perspectives for risk stratification can be outlined.

CONCLUSIONS

Data on promising biomarkers of severe aortic complications of MFS have been accumulating steadily. However, more unifying studies are required to further evaluate the applicability of the discussed predictors with the aim of improving the risk stratification and therefore the life expectancy and quality of life of MFS patients.

Aortic disease in Marfan syndrome is caused by overactivation of sGC-PRKG signaling by NO

Thoracic aortic aneurysm, as occurs in Marfan syndrome, is generally asymptomatic until dissection or rupture, requiring surgical intervention as the only available treatment. Here, we show that nitric oxide (NO) signaling dysregulates actin cytoskeleton dynamics in Marfan Syndrome smooth muscle cells and that NO-donors induce Marfan-like aortopathy in wild-type mice, indicating that a marked increase in NO suffices to induce aortopathy. Levels of nitrated proteins are higher in plasma from Marfan patients and mice and in aortic tissue from Marfan mice than in control samples, indicating elevated circulating and tissue NO. Soluble guanylate cyclase and cGMP-dependent protein kinase are both activated in Marfan patients and mice and in wild-type mice treated with NO-donors, as shown by increased plasma cGMP and pVASP-S239 staining in aortic tissue. Marfan aortopathy in mice is reverted by pharmacological inhibition of soluble guanylate cyclase and cGMP-dependent protein kinase and lentiviral-mediated Prkg1 silencing. These findings identify potential biomarkers for monitoring Marfan Syndrome in patients and urge evaluation of cGMP-dependent protein kinase and soluble guanylate cyclase as therapeutic targets.

Aortic aneurysm and dissection, the major problem linked to Marfan syndrome (MFS), lacks effective pharmacological treatment. Here, the authors show that the NO pathway is overactivated in MFS and that inhibition of guanylate cyclase and cGMP-dependent protein kinase reverts MFS aortopathy in mice.

Association between subjective well-being and perception of medical care system among patients with Marfan syndrome: A cross-sectional study

Background

This study investigated the association between subjective well‐being and perception for collaboration among clinical departments of adult Marfan syndrome (MFS) patients.

Methods

We performed a self‐administered questionnaire survey to ask about current medical treatment and support systems and subjective well‐being for 114 patients with MFS aged 18–64 years. It was hypothesized that patients’ perception of collaboration between clinical departments would raise their subjective well‐being. Mean value differences were predicted by a multiple regression analysis model, with supportive medical staff, age, sex, aorta dissection, family history, marriage status, and educational background adjusted.

Results

Patients’ perception of collaboration between clinical departments and being married raised SWLS scores (mean difference for patients’ perception of collaboration versus not = 3.41, 95% CI = 0.28, 6.53, p = .03; for married versus single = 5.22, 95% CI = 1.75, 8.69, p = .003).

Conclusion

Our results have suggested that it is necessary to maintain and enhance the medical treatment system with the patients for improving the subjective well‐being of MFS patients. In addition, the result indicated the need for intervention to the patients themselves and also their family so that it allows patients to receive physical and emotional support from people close to them.

Tele-Clinic Visits in Pediatric Patients with Marfan Syndrome Using Parentally Acquired Echocardiography

OBJECTIVE

To test feasibility of tele-clinic visits using parentally acquired vital signs and focused echocardiographic images in patients with Marfan syndrome.

STUDY DESIGN

We included patients with Marfan syndrome aged 5-19 years followed in our clinic. We excluded patients with Marfan syndrome and history of previous aortic root (AoR) surgery, cardiomyopathy, arrhythmia, or AoR ≥4.5 cm. We trained parents in-person to acquire focused echocardiographic images on their children using a hand-held device as well as how to use a stadiometer, scale, blood pressure (BP) machine, and a digital stethoscope. Before tele-clinic visits, parents obtained the echocardiographic images and vital signs. We compared tele-clinic and on-site clinic visit data. Parental and clinic echocardiograms were independently analyzed.

RESULTS

Fifteen patient/parent pairs completed tele-clinic visits, conducted at a median of 7.0 (IQR 3.0-9.9) months from the in-person training session. Parents took a median of 70 (IQR 60-150) minutes to obtain the height, weight, heart rate, BP, cardiac sounds, and echocardiographic images before tele-clinic visits. Systolic BP was greater on-site than at home (median +13 mm Hg, P = .014). Height, weight, diastolic BP, heart rate, and AoR measurements were similar.

CONCLUSIONS

This study provides information for implementing tele-clinic visits using parentally acquired vital signs and echocardiographic images in patients with Marfan syndrome. The results show that tele-clinic visits are feasible and that parents were able to obtain focused echocardiographic images on their children.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03581682.

Intraindividual comparison of 1.5 T and 3 T non-contrast MR angiography for monitoring of aortic root diameters in Marfan patients

BACKGROUND

Reproducible aortic diameter measurements are crucial for assessment of aortic growth and aneurysm formation in patients with Marfan syndrome. The objective of this study was to perform an intraindividual comparison of aortic measurements at 1.5 T and 3 T using non-contrast magnetic resonance angiography (MRA) in pre-surgical and post-surgical Marfan patients.

METHODS

Forty consecutive Marfan patients were retrospectively evaluated by ECG-gated 2D balanced steady-state free precession (bSSFP) MRA at 1.5 T and 3 T after 363 ± 58 days. 24 patients were before and 16 patients after aortic root surgery. Two readers independently measured aortic diameters at seven aortic levels and rated the image quality/image artifacts (1 = poor/severe, 4 = excellent/none). Contrast-to-noise ratio (CNR) and signal intensity slopes between aortic lumen and vessel walls were semiautomatically determined.

RESULTS

In pre-surgical Marfan patients, interobserver agreement of aortic root diameter measurements was significantly higher at 3 T compared to 1.5 T (p < 0.05). In post-surgical Marfan patients, image quality and artifacts were significantly worse at 3 T compared to 1.5 T (p < 0.05). CNR was higher at 3 T compared to 1.5 T at all aortic levels. Significantly steeper slopes of signal intensity curves were observed at 3 T at all aortic levels (p < 0.001).

CONCLUSIONS

In pre-surgical Marfan patients, non-contrast MRA provides higher reproducibility of aortic diameter measurements at 3 T compared to 1.5 T. In post-surgical Marfan patients, metallic implants result in significantly worse imaging artifacts and reduced image quality at 3 T compared to 1.5 T. Therefore, we propose to monitor the thoracic aorta with non-contrast MRA at 3 T in pre-surgical Marfan patients and at 1.5 T in post-surgical Marfan patients.

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

BACKGROUND

A proportion of de novo variants in patients affected by genetic disorders, particularly those with autosomal dominant (AD) inheritance, could be the consequence of somatic mosaicism in one of the progenitors. There is growing evidence that germline and somatic mosaicism are more common and play a greater role in genetic disorders than previously acknowledged. In Marfan syndrome (MFS), caused by pathogenic variants in the fibrillin-1 gene (FBN1) gene, approximately 25% of the disease-causing variants are reported as de novo. Only a few cases of parental mosaicism have been reported in MFS.

METHODS

Employing an amplicon-based deep sequencing (ADS) method, we carried out a systematic analysis of 60 parents of 30 FBN1 positive, consecutive patients with MFS with an apparently de novo pathogenic variant.

RESULTS

Out of the 60 parents studied (30 families), the majority (n=51, 85%) had a systemic score of 0, seven had a score of 1 and two a score of 2, all due to minor criteria common in the normal population. We detected two families with somatic mosaicism in one of the progenitors, with a rate of 6.6% (2/30) of apparently de novo cases.

CONCLUSIONS

The search for parental somatic mosaicism should be routinely implemented in de novo cases of MFS, to offer appropriate genetic and reproductive counselling as well as to reveal masked, isolated clinical signs of MFS in progenitors that may require specific follow-up.

Left atrial strain in the assessment of diastolic function: providing new insights into primary myocardial dysfunction in Marfan syndrome

Previous studies using conventional echocardiographic measurements have reported subclinical left ventricular (LV) diastolic abnormalities in patients with Marfan syndrome (MFS). Left atrial (LA) strain allows an accurate categorization of LV diastolic dysfunction. We aimed to characterize LV myocardial performance in a cohort of MFS patients using STE-derived measurements (LV and LA strain) along with conventional echocardiographic parameters. We studied 127 adult patients with MFS (no prior cardiac surgery or significant valvular regurgitation) and 38 healthy controls. We performed detailed echocardiograms and selected left atrial reservoir strain (LASr) as a surrogate of impaired relaxation. Additionally, we searched for possible determinants of LASr in patients with MFS, with a special focus on the elastic properties of the aorta. In spite of lower E-wave, septal and lateral e' velocities and average E/e' ratio in MFS patients, all participants had normal diastolic function according to current guidelines. MFS patients exhibited reduced LV global longitudinal strain (19.3 ± 2.6 vs 21.6 ± 2.1%, p < 0.001) and reduced LASr (32.9 ± 8.5 vs 43.3 ± 7.8%, p < 0.001) compared to controls. In the MFS cohort, we found weak significant (p < 0.05) correlations between LASr and certain parameters: E/A ratio (R = 0.258), E wave (R = 0.226), aortic distensibility (R = 0.222), stiffness index (R = - 0.216), LV ejection fraction (R = 0.214), lateral e' (R = 0.210), LV end-systolic volume index (R =  - 0.210), LV global longitudinal strain (R = 0.201), septal e' (R = 0.185). After multivariate analysis, only LV end-systolic volume index and E/A ratio maintained a weak independent association with LASr (R =  - 0.220; p = 0.017 and R = 0.199; p = 0.046, respectively). In conclusion, LASr is reduced in patients with MFS, which may represent an early stage of LV diastolic dysfunction. LASr is not determined by the elastic properties of the aorta, suggesting that impaired myocardial relaxation is a primary condition in MFS.

Mutation spectrum and genotype-phenotype correlations in Chinese congenital ectopia lentis patients

PURPOSE

To identify the spectrum and frequency of mutations in congenital ectopia lentis (CEL) and to investigate the correlations between genotype and clinical phenotype in Chinese CEL patients.

METHODS

Ninety-three participants with CEL were enrolled from March 2017 to April 2020. Ocular and systemic examinations were performed for each included patient. Genomic DNA from the included patients was analysed by whole-exome sequencing to detect mutations. Clinical manifestations were compared for different mutation subgroups.

RESULTS

Gene mutations were detected in 79 patients. Sixty-five were FBN1-associated, and most were related to Marfan syndrome (MFS). The FBN1 mutations mainly consisted of missense mutations (49/65) and were concentrated in the 5' region. Probands with missense mutations tend to show high corneal astigmatism (χ² = 3.98, P = 0.046) and severe lens dislocation (t = 2.90, P = 0.006) compared to premature termination codon (PTC) mutations.

CONCLUSIONS

Most Chinese CEL patients were identified as having FBN1 mutations. Those with missense mutations commonly showed severe ocular phenotypes; therefore, reinforced follow-up and long-term observation are required. These correlations implicated the crucial role of missense and cysteine-involving mutations in ocular phenotypes, which might be explained by dominant-negative and nonsense-mediated mRNA decay (NMD).

Marfan syndrome: whole-exome sequencing reveals de novo mutations, second gene and genotype-phenotype correlations in the Chinese population

Marfan syndrome (MFS) is a dominant monogenic disease caused by mutations in fibrillin 1 (FBN1). Cardiovascular complications are the leading causes of mortality among MFS. In the present study, a whole-exome sequencing of MFS in the Chinese population was conducted to investigate the correlation between FBNI gene mutation and MFS. Forty-four low-frequency harmful loci were identified for the FBN1 gene in HGMD database. In addition, 38 loci were identified in the same database that have not been related to MFS before. A strict filtering and screening protocol revealed two patients of the studied group have double mutations in the FBN1 gene. The two patients harboring the double mutations expressed a prominent, highly pathological phenotype in the affected family. In addition to the FBN1 gene, we also found that 27 patients had mutations in the PKD1 gene, however these patients did not have kidney disease, and 16 of the 27 patients expressed aortic related complications. Genotype-phenotype analysis showed that patients with aortic complications are older in the family, aged between 20 and 40 years.

Proof-of-Concept: Antisense Oligonucleotide Mediated Skipping of Fibrillin-1 Exon 52

Marfan syndrome is one of the most common dominantly inherited connective tissue disorders, affecting 2–3 in 10,000 individuals, and is caused by one of over 2800 unique FBN1 mutations. Mutations in FBN1 result in reduced fibrillin-1 expression, or the production of two different fibrillin-1 monomers unable to interact to form functional microfibrils. Here, we describe in vitro evaluation of antisense oligonucleotides designed to mediate exclusion of FBN1 exon 52 during pre-mRNA splicing to restore monomer homology. Antisense oligonucleotide sequences were screened in healthy control fibroblasts. The most effective sequence was synthesised as a phosphorodiamidate morpholino oligomer, a chemistry shown to be safe and effective clinically. We show that exon 52 can be excluded in up to 100% of FBN1 transcripts in healthy control fibroblasts transfected with PMO52. Immunofluorescent staining revealed the loss of fibrillin 1 fibres with ~50% skipping and the subsequent re-appearance of fibres with >80% skipping. However, the effect of exon skipping on the function of the induced fibrillin-1 isoform remains to be explored. Therefore, these findings demonstrate proof-of-concept that exclusion of an exon from FBN1 pre-mRNA can result in internally truncated but identical monomers capable of forming fibres and lay a foundation for further investigation to determine the effect of exon skipping on fibrillin-1 function.

Can polyunsaturated fatty acids regulate Polycystic Ovary Syndrome via TGF-β signalling?

Polycystic Ovary Syndrome (PCOS) is a metabolic condition that affects women in their reproductive age by altering the ovarian hormone levels, leading to infertility. Increased inflammation, insulin resistance, hyperandrogenism, irregular menses, and infertility are the causes of morbidity when PCOS is the disease in question. PCOS is considered a multifactorial disease resulting from the disruption of multiple signalling pathways. Hence, the mono-targeted drugs are hardly adequate and conventional therapeutic strategies provide only palliative care. Studies show that the consumption of polyunsaturated fatty acids (PUFAs) regulates menstrual cycle, decrease testosterone and insulin levels, and improve metabolic health. This could favourably affect diabetes and infertility. In recent years, the fibrillin-3 gene has been linked to PCOS. Fibrillins along with the molecules in the extracellular matrix modulate the Transforming Growth Factor-β (TGF-β) signalling. So, mutations in the fibrillin-3 gene could cause TGF-β dysregulation, which might further contribute to PCOS pathogenesis. Therefore, the current study aimed to understand whether PUFAs could manage PCOS via the TGF-β pathway and function as a therapeutic agent for PCOS and its complications. To understand this, we have focused on the involvement of TGF-β in PCOS pathogenesis, discussed the effect of PUFA on hormones, insulin resistance, inflammation, obesity, adiponectin, and cardiovascular conditions. Using PUFAs to target TGF-β or its receptor molecules to modulate the TGF-β production might function as a treatment option for PCOS. PUFA therapy could be a good alternative, supportive medication for PCOS.

Obstructive Sleep Apnea, Palatal Morphology, and Aortic Dilatation in Marfan Syndrome Growing Subjects: A Retrospective Study

The main cause of mortality in Marfan syndrome (MS) is aortic disease. Obstructive sleep apnea (OSA) is highly prevalent in MS, and it is also associated with cardiovascular risk and maxillary deformities. The aim of this research was to analyze the possible relations between OSA, palatal morphology, and aortic root diameters in growing subjects. A group of 15 growing subjects with MS and a control group of healthy peers was selected. All of them underwent nocturnal polygraphic monitoring, digital dental casts, and transthoracic echocardiography. The results showed that OSA indexes and aortic diameters were significantly higher in the study group. Transversal palatal dimension was smaller in MS patients. Moreover, OSA severity was not related with maxillary contraction severity in MS. No correlation between OSA severity and increased aortic diameters occurred. A high prevalence of OSA, increased aortic dimensions, and significant contraction of palatal dimensions were observed in MS compared with the control group. None of these single factors may directly be associated with aortic dilation, but together, they might contribute to the development and progression of aortic aneurysm from a young age.

Is Aortic Z-score an Appropriate Index of Beneficial Drug Effect in Clinical Trials in Aortic Aneurysm Disease?

Aortic Z-score (Z-score) is utilized in clinical trials to monitor the effect of medications on aortic dilation rate in Marfan (MFS) patients. Z-scores are reported in relation to body surface area and therefore are a function of height and weight. However, an information void exists regarding natural, non-pharmacological changes in Z-scores as children age. We had concerns that Z-score decrease attributed to "therapeutic" effects of investigational drugs for Marfan disease connective tissue diseases might simply reflect normal changes ("filling out" of body contour) as children age. This investigation studies natural changes with age in Z-score in normal and untreated MFS children, teasing out normal effects that might erroneously be attributed to drug benefit. (1) We first compared body mass index (BMI) and Z-scores (Boston Children's Hospital calculator) in 361 children with "normal" single echo exams in four age ranges (0 to 1, 5 to 7, 10 to 12, 15 to 18 years). Regression analysis revealed that aging itself decreases ascending Z-score, but not root Z-score, and that increase in BMI with aging underlies the decreased Z-scores. (2) Next, we examined Z-score findings in both "normal" and Marfan children (all pharmacologically untreated) as determined on sequential echo exams over time. Of 27 children without aortic disease with sequential echos, 19 (70%) showed a natural decrease in root Z-score and 24 (89%) showed a natural decrease in ascending Z- score, over time. Of 25 untreated MFS children with sequential echos, 12 (40%) showed a natural decrease in root Z-score and 10 (33%) showed a natural decrease in ascending Z-score. Thus, Z-score is over time affected by natural factors even in the absence of any aneurysmal pathology or medical intervention. Specifically, Z-score decreases spontaneously as a natural phenomenon as children age and with fill out their BMI. Untreated Marfan patients often showed a spontaneous decrease in Z-score. In clinical drug trials in aneurysm disease, decreasing Z-score has been interpreted as a sign of beneficial drug effect. These data put such conclusions into doubt.

Risk Factors and Inadequacy of Screening for Sleep-Disordered Breathing in Children with Marfan Syndrome

The prevalence of obstructive sleep apnea (OSA) is increased in children and adults with Marfan syndrome (MFS) compared to the general population and has been shown to be associated with rapid aortic root dilation and dissection in adults. Early diagnosis and treatment of OSA may decrease long-term cardiac morbidity. We therefore studied the utility of noninvasive OSA screening tools in children with MFS. We hypothesized that youth with MFS would have higher OSA screening scores than the general pediatric population. Subjects with confirmed MFS were recruited from a single pediatric center. Data collected included cardiac history, retrospective polysomnogram (PSG) data, and prospectively collected Pediatric Sleep Questionnaire (SRBD-PSQ) and Epworth Sleepiness Scale (ESS-CHAD) scores. Fifty-one individuals aged 2-21 years old were identified. Nineteen subjects completed the surveys, 53% female, median age 16 years. Of those that completed the survey, mean SRBD-PSQ score was 0.24 ± 0.21 and mean ESS-CHAD was 6.4 ± 3.7. Comparatively, published normative data for pediatric control subjects were 0.24 ± 0.21 for SRBD-PSQ and 5.4 ± 3.7 for ESS-CHAD. In conclusions, youth with MFS had similar OSA screening scores compared to published pediatric controls. Given these findings and high prevalence of OSA in MFS youth, standard questionnaires may not be an appropriate tool for identifying children at risk for OSA in this population. In the absence of evidence-based guidelines, physicians caring for children with MFS should consider referral for PSG, even in the absence of classic symptoms.

Giant Right Coronary Ostial Aneurysm in a Patient With Marfan Syndrome

Aortic root dilation and aortic insufficiency are prominent causes of morbidity in Marfan syndrome. These pathologies necessitate surgical repair, including aortic root and aortic valve replacement procedures, to improve prognosis. Coronary artery aneurysms, particularly giant coronary ostial aneurysms, are rare complications of these surgeries in the Marfan population. Due to the significant life-threatening sequelae of coronary artery aneurysms, it is imperative to bring attention regarding this complication to the radiologist assessing thoracic imaging in this patient population.

An aortopathy dilemma in pregnancy: A rare case report

BACKGROUND

The most dramatic diseases in the aorta are aortic dissection and aneurysm, which both of them are common in pregnant women with Marfan syndrome (MFS). According to recommendations in existing guidelines, pregnancy is not recommended in patients with severe dilation of the aorta and patients with MFS with aortic dilation > 45 mm should have prophylactic aortic repair before pregnancy.

CASE REPORT

In this rare and unique report, we described a 34-year-old pregnant woman with marfanoid feature who had an approximate aortic root of 60 mm and severe aortic insufficiency. She denied terminating the pregnancy at her first prenatal visit and continued it until 30 weeks of gestation and the pregnancy terminated in the cardiac operating room due to multiple episodes of chest pain. No complication occurred during her close observation before surgery. The aortic repair was performed for her after the cesarean section.

CONCLUSION

Pregnancy with severe aortic root dilation is high-risk for all patients; however, if it occurs, when the mother denies an abortion, inform the patient about its risk and continue the pregnancy with close observation and tight blood pressure (BP) control until the fetus becomes viable.

Maternal health and pregnancy outcome in diagnosed and undiagnosed Marfan syndrome: A registry-based study

In Marfan syndrome (MFS), pregnancy is considered as high risk due to the deficiency of fibrillin in the connective tissue and increased risk of aortic dissection. The objective was to demonstrate the consequences on maternal health, in women with diagnosed and undiagnosed MFS at the time of pregnancy and childbirth. By using national health care registries, we identified all pregnancy related outcomes, from women with MFS (n = 183) and an age-matched background population (n = 18,300). We found 91 pregnancies during follow-up. Significantly fewer women with MFS gave birth, compared to the background population. No women with known MFS had a pregnancy related aortic dissection but complications related to the cervix were increased (HR:19.8 [95% CI:2.2-177.5]). Fifty women with MFS were undiagnosed at the time of their first pregnancy and/or childbirth. Among these, there were more birth canal related complications HR:27.2 (95% CI: 2.3-315.0), preeclampsia (HR:2.25 [95% CI: 1.11-4.60]), fetal deaths (HR:12.3 [95% CI: 1.51-99.8]), and all delivery-related dissections came from this subgroup. In conclusion, undiagnosed women with MFS experienced more pregnancy and childbirth related complications including fetal death, birth canal issues, preeclampsia, and aortic disease, which emphasizes the need for an early MFS diagnosis and special care during pregnancy and childbirth.

Severe neonatal Marfan syndrome with a novel mutation in the intron of the FBN1 gene: A case report

RATIONALE

Marfan syndrome (MFS) has been defined as a genetic disorder that affects various systems such as the musculoskeletal, orbital, and cardiovascular systems. Neonatal MFS is considered rare and the most severe form of MFS is characterized by rapidly progressive atrioventricular valve dysfunction, often leading to death during early childhood due to congestive heart failure.

PATIENT CONCERNS

A newborn with neonatal MFS and severe cardiac involvement. He presented various severe clinical features such as arachnodactyly, camptodactyly, elbow and knee joint contracture, senile facial appearance, and deep settling with down-slanting palpebral fissure, hypoplastic ear cartilage, sagging mouth, brachycephaly, and ectopia lentis.

DIAGNOSIS

Genetic analysis revealed a novel mutation at nucleotide 3964 (c.3964 + 1 G > T) in intron 32 of the fibrillin-1 gene. This mutation is identified to be in the so-called neonatal region of fibrillin-1 exon 24 to 32, as reported previously.

INTERVENTIONS

The patient was managed medically for improving the low cardiac output according to severe mitral regurgitation and aortic regurgitation. Afterload reduction, full sedation, and use of diuretic were attempted to improve the oliguria and heart failure.

OUTCOMES

Despite the medical management, aortic regurgitation, mitral regurgitation, pulmonary hypertension, and cardiac contractility got worse. Surgical treatment is essential to prolong the patient's life, however, considerations for the grave progression of the disease make families decide to continue palliative care instead of surgical treatment. A few months after birth, he presented with rapidly progressive aortic regurgitation, mitral regurgitation, and congestive heart failure leading to death.

CONCLUSIONS

This review demonstrated the prominent characteristics of neonatal MFS mutations, it would be helpful for the recognition of novel neonatal MFS variants and valuable for the understanding of the genotype-phenotype correlations and using the plans for managements and counseling in neonatal MFS.

Outcomes of three surgical approaches for managing ectopia lentis in Marfan syndrome

OBJECTIVE

To investigate the clinical outcomes of three surgical approaches for ectopia lentis in Marfan syndrome (MS) patients who had undergone crystalline lens removal with posterior chamber intraocular lens (IOL) implantation techniques comprising the intrascleral fixation of IOL, sutured scleral fixation of IOL, and IOL implantation with the use of a Cionni capsular tension ring (CTR).

METHODS

This is a retrospective comparative study, including 35 eyes of 21 patients who underwent the intrascleral fixation of IOL (group 1), scleral IOL fixation with the Z-suture (group 2), and IOL implantation with the use of a Cionni CTR (group 3) following crystalline lens removal. The surgical indications were as follows: no improvement in visual function after eyeglasses or contact lens application due to excessive irregular astigmatism and advanced crystalline lens decentration in which the edge of the crystalline lens came up to the optical axis, or dislocation of the crystalline lens resulting in aphakia and secondary glaucoma due to lens dislocation. The surgical outcomes and complications due to surgery were compared between the groups.

RESULTS

The mean age of the patients in the study was 12.3 ± 8.7 years (5-32 years). There were 10 eyes in group 1, 13 eyes in group 2, and 12 eyes in group 3. Visual acuity improved significantly in each group after surgery. Ocular residual astigmatism did not differ significantly between the groups (p = 0.51).

CONCLUSION

There were no significant differences between the three surgical approaches in the current study in terms of the postoperative results and complications.

Visual outcomes of lens subluxation surgery with Cionni modified capsular tension rings in Marfan syndrome

Marfan syndrome (MFS) is a hereditary disease with an incidence of 0.3% in the general population. Approximately 60% of MFS patients with FBN1 gene mutation will suffer ectopia lentis (EL) from the age of 3. With the development of EL, severe loss of vision will accrue because of lens tilt and glaucoma. Cionni modified capsular tension rings (MCTR) has been applied in the surgery for EL in MFS patients. To evaluate visual acuity and safety of using MCTR during lens subluxation surgery in MFS patients, 66 MFS patients (110 eyes) were included in our study, with the mean duration of follow-up of 4.7 months (SD 1.76 months). The capsular bags were preserved in 101 eyes (91.81%) with MCTR implantation. There was an overall significant improvement in BCVA at 1-month follow-up which was maintained at 3 months. Multivariable linear regression revealed that older age at first visit was associated with greater postoperative BCVA at the 1-month follow-up (P = 0.007). A significant difference was found between different degrees of lens subluxation and the length of surgical time and complications. At follow-up, only two eyes (1.98%) were identified to have developed retinal detachments. In conclusion, better visual outcomes can be achieved when patients received an early operation with MCTR implantation.

Accuracy of intraocular lens calculation formulas for eyes with insufficient capsular support

Background

There is no consensus on which intraocular lens (IOL) power calculation formula provides the best refractive prediction in patients with inadequate capsular support whose anterior ocular anatomic structure differs from that of normal subjects. Therefore, the purpose of this study was to analyze the accuracy and performance of IOL calculation formulas (SRK/T, Holladay 1, Hoffer Q, Haigis, and Barrett Universal II) in predicting postoperative refractive prediction error (PE) for this subgroup of patients.

Methods

A total of 110 eyes from 110 patients with insufficient capsular support who underwent scleral fixation of an IOL at the Zhongshan Ophthalmic Center from July 1, 2016 to November 30, 2019 were enrolled in this retrospective study. Preoperative optical biometrics were measured with the IOL Master 500 (Carl Zeiss, Oberkochen, Germany). The performance of each formula in predicting PE was compared, and the effect of keratometry and axial length (AL) on PE was evaluated for each formula using univariate and multivariate linear regression analysis.

Results

The mean age of the included participants was 12.54±9.66 years. The Sanders, Retzlaff, and Manus/theoretical (SRK/T) (-0.25 D) and Holladay 1 (-0.28 D) formulas tended to have minimal postoperative PE compared to the Hoffer Q (-0.62 D), Haigis (-0.67 D), and Barrett Universal II (-0.62 D) formulas (P=0.005). All formulas individually resulted in <70% of eyes within ±1.00 D of the PE. Nevertheless, after constants were optimized, these formulas led to 7.3% to 13.6% of increase within ±1.00 D of the PE. Keratometry and AL were significantly associated with PE for each formula, but the relationship was weakest for SRK/T.

Conclusions

In eyes with insufficient capsular support, postoperative PE was minimal for the SRK/T formula, which suggested SRK/T to be the best choice, especially when the keratometry and AL of patients are extremely large or small.

Thoracic aortic aneurysms in patients with heritable connective tissue disease

BACKGROUND

Patients with connective tissue diseases are at high lifetime risk of developing thoracic aortic aneurysms (TAAs) due to defects in extracellular matrix composition which compromise the structural integrity of the aortic wall. It is vital to identify and manage aneurysms early to prevent fatal complications such as dissection or rupture.

METHOD

This review synthesises information obtained from a thorough literature search regarding the pathophysiology of TAAs in those with heritable connective tissue diseases (HCTDs), the investigations for timely diagnosis and current operative strategies.

RESULTS

Major complications of open repair (OR) include pneumonia (32%), haemorrhage (31%) and tracheostomy (18%), with a minor risk of vocal cord paresis (9%). For thoracic endovascular aortic repair (TEVAR), high rates of endoleak were documented (38-66.6%). Reintervention rates for TEVAR are also high at 38-44%. Mortality rates were documented as 25% for open repair and vary from 14% to 44% for TEVAR.

CONCLUSION

OR remains the mainstay of surgical management. While TEVAR use is expanding, it remains the alternative choice due to concerns over endograft durability, limited long-term outcome data and the lack of high-quality evidence regarding its use in HCTD patients.

Inhibition of lysyl oxidase stimulates TGF-β signaling and metalloproteinases-2 and -9 expression and contributes to the disruption of ascending aorta in rats: protection by propylthiouracil

Mutations in lysyl oxidase (LOX) genes cause severe vascular anomalies in mice and humans. LOX activity can be irreversibly inhibited by the administration of β-aminoproprionitrile (BAPN). We investigated the mechanisms underlying the damage to the ascending thoracic aorta induced by LOX deficiency and evaluated whether 6-propylthiouracil (PTU) can afford protection in rats. BAPN administration caused disruption of the ascending aortic wall, increased the number of apoptotic cells, stimulated TGF-β signaling (increase of nuclear p-SMAD2 staining), and up-regulated the expression of metalloproteinases-2 and -9. In BAPN-treated animals, PTU reduced apoptosis, p-SMAD2 staining, MMP-2, and -9 expression, and markedly decreased the damage to the aortic wall. Our results suggest that, as in some heritable vascular diseases, enhanced TGF-β signaling and upregulation of MMP-2 and -9 can contribute to the pathogenesis of ascending aorta damage caused by LOX deficiency. We have also shown that PTU, a drug already in clinical use, protects against the effects of LOX inhibition. MMP-2 and -9 might be potential targets of new therapeutic strategies for the treatment of vascular diseases caused by LOX deficiency.

Reprogramming of a human induced pluripotent stem cell line from a Marfan syndrome patient harboring a heterozygous mutation of c.2939G > A in FBN1 gene

Marfan syndrome (MFS) is a connective-tissue disorder caused mainly by heterozygous mutations in the FBN1 gene that encodes fibrillin-1. In this study, human induced pluripotent stem cell (iPSC) line ZZUSAHi003-A was generated from peripheral blood mononuclear cells (PBMCs) isolated from a female patient with MFS using non-integrative Sendai virus. The iPSC line carried the FBN1 gene mutation, showed the normal karyotype, expressed pluripotency markers and had the capacity to differentiate into three germ layers in vivo. This iPS line, ZZUSAHi003-A, could serve as a useful tool for studying pathogenic mechanisms of MFS.

The Molecular Genetics of Marfan Syndrome

Marfan syndrome (MFS) is a complex connective tissue disease that is primarily characterized by cardiovascular, ocular and skeletal systems disorders. Despite its rarity, MFS severely impacts the quality of life of the patients. It has been shown that molecular genetic factors serve critical roles in the pathogenesis of MFS. FBN1 is associated with MFS and the other genes such as FBN2, transforming growth factor beta (TGF-β) receptors (TGFBR1 and TGFBR2), latent TGF-β-binding protein 2 (LTBP2) and SKI, amongst others also have their associated syndromes, however high overlap may exist between these syndromes and MFS. Abnormalities in the TGF-β signaling pathway also contribute to the development of aneurysms in patients with MFS, although the detailed molecular mechanism remains unclear. Mutant FBN1 protein may cause unstableness in elastic structures, thereby perturbing the TGF-β signaling pathway, which regulates several processes in cells. Additionally, DNA methylation of FBN1 and histone acetylation in an MFS mouse model demonstrated that epigenetic factors play a regulatory role in MFS. The purpose of the present review is to provide an up-to-date understanding of MFS-related genes and relevant assessment technologies, with the aim of laying a foundation for the early diagnosis, consultation and treatment of MFS.

Cardiomyopathy in Genetic Aortic Diseases

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

Marfan syndrome and the eye clinic: from diagnosis to management

Marfan syndrome (MFS) is an autosomal dominantly inherited disorder affecting the cardiovascular, ocular and musculoskeletal systems. Frequently, clinical suspicion and subsequent diagnosis begins in the ophthalmology clinic. Importantly, the ophthalmologist has a responsibility to cater not only to the eye, but also to be involved in a holistic approach for these patients. In this review, we discuss how MFS may present to an eye clinic, including clinical features, ocular morbidity, genetic diagnosis and management. Although this condition is ideally managed by a multidisciplinary team, our focus will be on MFS and the eye, including other conditions which may present with similar phenotypes. The ophthalmologist's role as the potential first contact for a patient with suspected MFS is crucial in making the proper investigations and referral, with the knowledge that not all ectopia lentis cases are MFS and vice versa. Management of ocular conditions in MFS may range from simple observation to surgical intervention; current options will be discussed.

Epidemiology and management of aortic disease: aortic aneurysms and acute aortic syndromes

The aorta is the 'greatest artery', through which oxygenated blood is delivered from the left ventricle to end organs with each cardiac cycle (200 million litres of blood transported in an average lifetime). The aorta can be affected by a wide spectrum of acute factors (such as cocaine use, weight lifting and trauma) and chronic acquired and/or genetic conditions (such as systemic arterial hypertension and phaeochromocytoma), which variously lead to increased aortic wall stress. The medial layer of the aorta can also be subject to abnormalities (such as Marfan syndrome, bicuspid aortic valve, inflammatory vasculitis, atherosclerosis and infections). Despite important advances in diagnostic and therapeutic interventions, data derived from registries and population-based studies highlight that the burden of aortic diseases remains high. Therefore, specific resources need to be allocated to design and implement preventive strategies (healthy lifestyles, modifications to cardiovascular risk factors, and educational and screening programmes) at individual and community levels. In this Review, we discuss the epidemiology, management and outcomes of the most common aortic diseases, namely, aortic aneurysms and acute aortic syndromes.

Transforming Growth Factor-β and the Renin-Angiotensin System in Syndromic Thoracic Aortic Aneurysms: Implications for Treatment

Thoracic aortic aneurysms (TAAs) are permanent pathological dilatations of the thoracic aorta, which can lead to life-threatening complications, such as aortic dissection and rupture. TAAs frequently occur in a syndromic form in individuals with an underlying genetic predisposition, such as Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). Increasing evidence supports an important role for transforming growth factor-β (TGF-β) and the renin-angiotensin system (RAS) in TAA pathology. Eventually, most patients with syndromic TAAs require surgical intervention, as the ability of present medical treatment to attenuate aneurysm growth is limited. Therefore, more effective medical treatment options are urgently needed. Numerous clinical trials investigated the therapeutic potential of angiotensin receptor blockers (ARBs) and β-blockers in patients suffering from syndromic TAAs. This review highlights the contribution of TGF-β signaling, RAS, and impaired mechanosensing abilities of aortic VSMCs in TAA formation. Furthermore, it critically discusses the most recent clinical evidence regarding the possible therapeutic benefit of ARBs and β-blockers in syndromic TAA patients and provides future research perspectives and therapeutic implications.

Health-related quality of life in Marfan syndrome: a 10-year follow-up

Background

Marfan syndrome, a rare hereditary connective tissue disorder caused by mutations in fibrillin-1, can affect many organ systems, especially the cardiovascular system. Previous research has paid less attention to health-related quality of life and prospective studies on this topic are needed. The aim of this study was to assess changes in health-related quality of life after 10 years in a Norwegian Marfan syndrome cohort.

Methods

Forty-seven Marfan syndrome patients ≥ 18 years were investigated for all organ manifestations in the 1996 Ghent nosology and completed the self-reported questionnaire, Short-Form-36 Health Survey, at baseline in 2003–2004 and at follow-up in 2014–2015. Paired sample t tests were performed to compare means and multiple regression analyses were performed with age, sex, new cardiovascular and new non-cardiovascular pathology as predictors.

Results

At 10-year follow-up: a significant decline was found in the physical domain. The mental domain was unchanged. Older age predicted a larger decline in physical health-related quality of life. None of the chosen Marfan-related variables predicted changes in any of the subscales of the Short-Form 36 Health Survey or in the physical or the mental domain.

Conclusion

Knowledge of decline in the physical domain, not related to organ affections, may be important in the follow-up of Marfan syndrome patients.

Quantitative proteomics reveal lineage-specific protein profiles in iPSC-derived Marfan syndrome smooth muscle cells

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the FBN1 gene that produces wide disease phenotypic variability. The lack of ample genotype-phenotype correlation hinders translational study development aimed at improving disease prognosis. In response to this need, an induced pluripotent stem cell (iPSC) disease model has been used to test patient-specific cells by a proteomic approach. This model has the potential to risk stratify patients to make clinical decisions, including timing for surgical treatment. The regional propensity for aneurysm formation in MFS may be related to distinct smooth muscle cell (SMC) embryologic lineages. Thus, peripheral blood mononuclear cell (PBMC)-derived induced pluripotent stem cells (iPSC) were differentiated into lateral mesoderm (LM, aortic root) and neural crest (NC, ascending aorta/transverse arch) SMC lineages to model MFS aortic pathology. Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) proteomic analysis by tandem mass spectrometry was applied to profile LM and NC iPSC SMCs from four MFS patients and two healthy controls. Analysis revealed 45 proteins with lineage-dependent expression in MFS patients, many of which were specific to diseased samples. Single protein-level data from both iPSC SMCs and primary MFS aortic root aneurysm tissue confirmed elevated integrin αV and reduced MRC2 in clinical disease specimens, validating the iPSC iTRAQ findings. Functionally, iPSC SMCs exhibited defective adhesion to a variety of extracellular matrix proteins, especially laminin-1 and fibronectin, suggesting altered cytoskeleton dynamics. This study defines the aortic embryologic origin-specific proteome in a validated iPSC SMC model to identify novel protein markers associated with MFS aneurysm phenotype. Translating iPSC findings into clinical aortic aneurysm tissue samples highlights the potential for iPSC-based methods to model MFS disease for mechanistic studies and therapeutic discovery in vitro.

Differential diagnosis of Marfan syndrome based on ocular biologic parameters

Background

The present study aimed to investigate the ocular characteristics of Chinese patients with Marfan syndrome (MFS) and to evaluate the sensitivity and specificity of ocular parameters in distinguishing MFS from ectopia lentis.

Methods

A total of 103 patients (103 eyes) with ectopia lentis from 13 provinces and 47 cities were recruited from Zhongshan Ophthalmic Center, Sun Yat-sen University, from June 2017 to June 2019. Ghent-2 criteria were used, as they are the gold standard diagnostic criteria for MFS. Ocular parameters, such as flat keratometry (Kf), steep keratometry (Ks), mean keratometry (Km), corneal astigmatism (AST), axial length (AL), white-to-white corneal diameter (WTW), central corneal thickness (CCT), and axial length/curvature radius (AL/CR), were recorded. Diagnostic analyses based on various combinations of parameters to differentiate MFS from ectopia lentis were made using receiver-operating characteristic (ROC) curves.

Results

The mean age of the 103 included patients was 10.25±9.67 (range: 3–48) years, and 66.02% were male. Km combined with CCT was found to have good sensitivity and specificity in the differential diagnosis of MFS from ectopia lentis; Km of 41.36 D and CCT of 537.32 mm were found to be the optimal cut-off points, representing a sensitivity of 89.8% and specificity of 68.7%.

Conclusions

Special characteristics of ocular parameters were detected in MFS. Our findings indicate that ocular biologic parameters are valuable for the differential diagnosis of MFS from ectopia lentis. Km, combined with CCT, could be used as a screening tool for MFS.

Ulnar Artery Aneurysm as a Late Sequela of Marfan Syndrome

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations of the FBN1 gene encoding fibrillin-1, which leads to overexpression of transforming growth factor-β, increased hyaluronan deposition, and matrix metalloproteinase activity in the media of the aorta and other muscular arteries. Marfan syndrome patients present with connective tissue laxity and aneurysmal changes to muscular arteries. Successful medical and surgical intervention has prolonged the life expectancy of MFS patients, which can allow atypical presentations of the syndrome to manifest. We present a case of a 49-year-old man with MFS who developed an ulnar artery aneurysm that was treated by excision and vein grafting.

Maternal, pregnancy, and neonatal outcomes for women with Marfan syndrome

BACKGROUND

Marfan syndrome (MFS) is an autosomal dominant hereditary disorder which affects cardiovascular structure and function. With medical advances, more women with MFS experience pregnancy, which may increase maternal and neonatal risk. Existing research has been limited by small or clinical samples. This study examines the association of MFS and adverse maternal, neonatal, and obstetric outcomes.

METHODS

We conducted a cross-sectional study using the discharge abstract database, containing all labor and delivery hospitalizations in Canada (excluding Quebec) from fiscal years 2004-2015 where women delivered a live- or stillbirth. We measured maternal and neonatal morbidity, preterm births (<37 weeks), small-for-gestational-age births, perinatal mortality, and adverse maternal cardiovascular events. For each outcome, we calculated the absolute risk for women with and without MFS and used generalized estimating equations with a logit function to calculate odds.

RESULTS

Overall, 2,682,461 women delivered a live or stillborn infant in Canada during the study period, with 135 birth events to women with MFS. Women with MFS did not have significantly higher odds of severe maternal morbidity during their delivery (aOR:1.3; 95%CI: 0.4-4.0). Similarly, their infants did not have significantly higher odds of neonatal morbidity. However, infants born to women with MFS were significantly more likely to be born preterm (aOR:2.6; 95%CI: 1.6-4.3) and to be small-for-gestational-age (aOR:1.8; 95%CI:1.0-3.1).

CONCLUSIONS

This population-based study indicates that, although some women with MFS may experience higher odds of maternal and/or neonatal morbidity during labor and delivery, the majority of women with MFS can have healthy births with proper clinical management.

Generation of a Matrix Gla (Mgp) floxed mouse, followed by conditional knockout, uncovers a new Mgp function in the eye

The ability to ablate a gene in a given tissue by generating a conditional knockout (cKO) is crucial for determining its function in the targeted tissue. Such tissue-specific ablation is even more critical when the gene's conventional knockout (KO) is lethal, which precludes studying the consequences of its deletion in other tissues. Therefore, here we describe a successful strategy that generated a Matrix Gla floxed mouse (Mgp.floxed) by the CRISPR/Cas9 system, that subsequently allowed the generation of cKOs by local viral delivery of the Cre-recombinase enzyme. MGP is a well-established inhibitor of calcification gene, highly expressed in arteries' smooth muscle cells and chondrocytes. MGP is also one of the most abundant genes in the trabecular meshwork, the eye tissue responsible for maintenance of intraocular pressure (IOP) and development of Glaucoma. Our strategy entailed one-step injection of two gRNAs, Cas9 protein and a long-single-stranded-circular DNA donor vector (lsscDNA, 6.7 kb) containing two loxP sites in cis and 900-700 bp 5'/3' homology arms. Ocular intracameral injection of Mgp.floxed mice with a Cre-adenovirus, led to an Mgp.TMcKO mouse which developed elevated IOP. Our study discovered a new role for the Mgp gene as a keeper of physiological IOP in the eye.

Androgens Accentuate TGF-β Dependent Erk/Smad Activation During Thoracic Aortic Aneurysm Formation in Marfan Syndrome Male Mice

Background Male patients with Marfan syndrome have a higher risk of aortic events and root dilatation compared with females. The role androgens play during Marfan syndrome aneurysm development in males remains unknown. We hypothesized that androgens potentiate transforming growth factor beta induced Erk (extracellular-signal-regulated kinase)/Smad activation, contributing to aneurysm progression in males. Methods and Results Aortic diameters in Fbn1C1039G/+ and littermate wild-type controls were measured at ages 6, 8, 12, and 16 weeks. Fbn1C1039G/+ males were treated with (1) flutamide (androgen receptor blocker) or (2) vehicle control from age 6 to 16 weeks and then euthanized. p-Erk1/2, p-Smad2, and matrix metalloproteinase (MMP) activity were measured in ascending/aortic root and descending aorta specimens. Fbn1C1039G/+ male and female ascending/aortic root-derived smooth muscle cells were utilized in vitro to measure Erk/Smad activation and MMP-2 activity following dihydrotestosterone, flutamide or transforming growth factor beta 1 treatment. Fbn1C1039G/+ males have increased aneurysm growth. p-Erk1/2 and p-Smad2 were elevated in ascending/aortic root specimens at age 16 weeks. Corresponding with enhanced Erk/Smad signaling, MMP-2 activity was higher in Fbn1C1039G/+ males. In vitro smooth muscle cell studies revealed that dihydrotestosterone potentiates transforming growth factor beta-induced Erk/Smad activation and MMP-2 activity, which is reversed by flutamide treatment. Finally, in vivo flutamide treatment reduced aneurysm growth via p-Erk1/2 and p-Smad2 reduction in Fbn1C1039G/+ males. Conclusions Fbn1C1039G/+ males have enhanced aneurysm growth compared with females associated with enhanced p-Erk1/2 and p-Smad2 activation. Mechanistically, in vitro smooth muscle cell studies suggested that dihydrotestosterone potentiates transforming growth factor beta induced Erk/Smad activation. As biological proof of concept, flutamide treatment attenuated aneurysm growth and p-Erk1/2 and p-Smad2 signaling in Fbn1C1039G/+ males.

Spinal fusion in pediatric patients with marfan syndrome: a nationwide assessment on short-term outcomes and readmission risk

PURPOSE

The purpose of this study was to utilize the National Readmission Database (NRD) to determine estimates for complication rates, 90-day readmission rates, and hospital costs associated with spinal fusion in pediatric patients with Marfan syndrome.

METHODS

The 2012-2015 NRD databases were queried for all pediatric (< 19 years old) patients diagnosed with Marfan syndrome undergoing spinal fusion surgery. The primary outcome variables in this study were index admission complications and 90-day readmissions.

RESULTS

A total of 249 patients with Marfan syndrome underwent spinal fusion surgery between 2012 and 2015 (mean age ± standard deviation at the time of surgery: 14 ± 2.0, 132 (53%) female). 25 (10.1%) were readmitted within 90 days of the index hospital discharge date. Overall, 59.7% of patients experienced at least one complication during the index admission. Unplanned 90-day readmission could be predicted by older age (odds ratio 2.3, 95% confidence interval 1.3-4.2, p = 0.006), Medicaid insurance status (56.0, 3.8-820.0, p = 0.003), and experiencing an inpatient medical complication (42.9, 4.6-398.7, p = 0.001). Patients were readmitted for wound dehiscence (8 patients, 3.2%), nervous system related complications (3 patients, 1.2%), and postoperative infectious related complications (4 patients, 1.6%).

CONCLUSION

This study is the first to demonstrate on a national level the complications and potential risk factors for 90-day hospital readmission for patients with Marfan syndrome undergoing spinal fusion. Patients with Marfan syndrome undergoing spinal fusion often present with multiple medical comorbidities that must be managed carefully perioperatively to reduce inpatient complications and early hospital readmissions.

Optimising the mutation screening strategy in Marfan syndrome and identifying genotypes with more severe aortic involvement

Background

Marfan syndrome (MFS) is a systemic connective tissue disorder with life-threatening manifestations affecting the ascending aorta. MFS is caused by dominant negative (DN) and haploinsufficient (HI) mutations of the FBN1 gene. Our aim was to identify mutations of MFS patients with high detection rate and to investigate the use of a gene panel for patients with Marfanoid habitus. We also aimed to examine correlations between genotype and cardiovascular manifestations to predict “malignant” mutations.

Methods

136 individuals were enrolled. In the first phase, next-generation sequencing (NGS) and Sanger sequencing were performed for 57 patients to screen the FBN1 gene, followed by multiplex ligation-dependent probe amplification (MLPA) in negative cases. For repeated negative results, NGS gene panel involving 9 genes was used. In the second phase, 79 patients were tested primarily with the same gene panel, negative samples were tested by MLPA.

Results

84 pathogenic mutations were detected, out of which 78 affected FBN1, 6 non-FBN1 mutations (2 TGFB2, 1 TGFBR2, 2 TGFBR1, 1 SMAD3) are associated with Loeys-Dietz syndrome (LDS). LDS patients had lower systemic score and they were younger, but their aortic involvement did not differ. MLPA detected 4 multi-exon deletions of FBN1 gene, which could not be identified by our first-step screening method. Aortic involvement (aortic dissection and/or dilation) did not differ significantly among HI and DN mutations (p = 0.061). Combined group of HI and DN mutations eliminating a disulphide-bonding cysteine (DN Cys) had significantly higher aortic involvement rate than DN mutations not eliminating a disulphide-bonding cysteine (DN non-Cys) (p < 0.001). Patients with DN Cys required significantly more aortic surgeries than HI and DN non-Cys mutations (p = 0.042 and p = 0.015, respectively).

Conclusions

Due to the relevant number of mutations affecting genes other than FBN1, preferred approach for testing individuals with Marfanoid habitus is using a gene panel rather than single-gene analysis, followed by MLPA for negative samples. DN Cys and HI mutations should be considered as risk factors for aortic involvement. Genetic testing for patients with Marfanoid features and a systemic score under 7 is recommended, as LDS patients may have lower scores, but they may have severe cardiovascular manifestations.

Steered molecular dynamic simulations reveal Marfan syndrome mutations disrupt fibrillin-1 cbEGF domain mechanosensitive calcium binding

Marfan syndrome (MFS) is a highly variable genetic connective tissue disorder caused by mutations in the calcium binding extracellular matrix glycoprotein fibrillin-1. Patients with the most severe form of MFS (neonatal MFS; nMFS) tend to have mutations that cluster in an internal region of fibrillin-1 called the neonatal region. This region is predominantly composed of eight calcium-binding epidermal growth factor-like (cbEGF) domains, each of which binds one calcium ion and is stabilized by three highly conserved disulfide bonds. Crucially, calcium plays a fundamental role in stabilizing cbEGF domains. Perturbed calcium binding caused by cbEGF domain mutations is thus thought to be a central driver of MFS pathophysiology. Using steered molecular dynamics (SMD) simulations, we demonstrate that cbEGF domain calcium binding decreases under mechanical stress (i.e. cbEGF domains are mechanosensitive). We further demonstrate the disulfide bonds in cbEGF domains uniquely orchestrate protein unfolding by showing that MFS disulfide bond mutations markedly disrupt normal mechanosensitive calcium binding dynamics. These results point to a potential mechanosensitive mechanism for fibrillin-1 in regulating extracellular transforming growth factor beta (TGFB) bioavailability and microfibril integrity. Such mechanosensitive “smart” features may represent novel mechanisms for mechanical hemostasis regulation in extracellular matrix that are pathologically activated in MFS.

C. elegans Apical Extracellular Matrices Shape Epithelia

Apical extracellular matrices (aECMs) coat exposed surfaces of epithelia to shape developing tissues and protect them from environmental insults. Despite their widespread importance for human health, aECMs are poorly understood compared to basal and stromal ECMs. The nematode Caenorhabditis elegans contains a variety of distinct aECMs, some of which share many of the same types of components (lipids, lipoproteins, collagens, zona pellucida domain proteins, chondroitin glycosaminoglycans and proteoglycans) with mammalian aECMs. These aECMs include the eggshell, a glycocalyx-like pre-cuticle, both collagenous and chitin-based cuticles, and other understudied aECMs of internal epithelia. C. elegans allows rapid genetic manipulations and live imaging of fluorescently-tagged aECM components, and is therefore providing new insights into aECM structure, trafficking, assembly, and functions in tissue shaping.

A multi-layered and dynamic apical extracellular matrix shapes the vulva lumen in Caenorhabditis elegans

Biological tubes must develop and maintain their proper diameter to transport materials efficiently. These tubes are molded and protected in part by apical extracellular matrices (aECMs) that line their lumens. Despite their importance, aECMs are difficult to image in vivo and therefore poorly understood. The Caenorhabditis elegans vulva has been a paradigm for understanding many aspects of organogenesis. Here we describe the vulva luminal matrix, which contains chondroitin proteoglycans, Zona Pellucida (ZP) domain proteins, and other glycoproteins and lipid transporters related to those in mammals. Confocal and transmission electron microscopy revealed, with unprecedented detail, a complex and dynamic aECM. Different matrix factors assemble on the apical surfaces of each vulva cell type, with clear distinctions seen between Ras-dependent (1°) and Notch-dependent (2°) cell types. Genetic perturbations suggest that chondroitin and other aECM factors together generate a structured scaffold that both expands and constricts lumen shape.

Management of a giant aortic root aneurysm in a young patient with Marfan syndrome: a case report

Introduction

Marfan syndrome (MFS) is a common heritable connective tissue disease involving multiple organs. Even though the clinical manifestations of MFS can be various, aortic root aneurysm is estimated as one of the most serious complications. We herein describe an individualized treatment decision-making process for a 23-year-old male with MFS, suffering from a giant but stable aortic root aneurysm which is extremely rare at his age.

Case

The patient, a 23-year-old male with a family history of MFS, presented to our cardiovascular department because of progressive exertional chest distress, fatigue and occasional precordial pain. Physical examinations revealed 190.5 cm of height, high myopia, and a diastolic murmur at the aortic valve area. Laboratory examinations for systemic vasculitis and infectious diseases were negative. Transthoracic echocardiography and enhanced thoracic computed tomography (CT) scan revealed the existence of a giant aortic root aneurysm (125.1 mm in short-axis), severe aortic valve regurgitation, cardiac dilatation (LV; 99 mm in diastolic diameter) and a poor ejection fraction (EF; 18%). Considering the risk of rupture or dissection of the dilated aortic root, we performed Bentall procedure based on the results of multidisciplinary team discussion and intraoperative exploration. Postoperative thoracic CT scan revealed a normal sized reconstructed aortic root, and the patient was discharged uneventfully 7 days later.

Conclusion

It is extremely rare to report such a giant aortic root aneurysm in a young patient. In the treatment decision-making process, the patient’s specific situation should be taken into consideration. A mechanical Bentall procedure seems to be an acceptable option for some selected cases.

Pleural changes in patients with pneumothoraces and Marfan syndrome

Background

Patients with Marfan syndrome (MFS) often develop pneumothorax, but the features of pneumothorax in the context of MFS have not been well described in the literature. We clarified the clinical and histopathological characteristics of this condition in these patients.

Methods

Patients with MFS were selected from among all patients who underwent surgery for pneumothorax, between December 1991 and January 2015, in our hospital. We studied the histopathological characteristics of the resected lungs as well as the clinical features of the selected patients, including surgical findings and postoperative recurrence status.

Results

There were 966 operations underwent pneumothorax-related surgeries in our hospital. A total of 16 operations (1.66%) were performed on patients with MFS in 11 cases. In this study, 9 patients (6 men, 3 women) were included. Clinically, 7 patients (77.8%) had bilateral pneumothoraces and 4 (44.4%) exhibited postoperative recurrent pneumothoraces. Pathologically, the resected pulmonary bullae exhibited blood vessel cystic medial degeneration (55.6% of cases), calcification (55.6% of cases), and demonstrated elastic fiber fragmentation and degeneration (all cases).

Conclusions

As in few previous reports, many patients with MFS develop bilateral or postoperative recurrent pneumothoraces. In many patients, characteristic changes in the pulmonary bullae, possibly caused by degenerated elastic fibers, were observed.

Single-Cell Transcriptomic Profiling of Vascular Smooth Muscle Cell Phenotype Modulation in Marfan Syndrome Aortic Aneurysm

OBJECTIVE

To delineate temporal and spatial dynamics of vascular smooth muscle cell (SMC) transcriptomic changes during aortic aneurysm development in Marfan syndrome (MFS). Approach and Results: We performed single-cell RNA sequencing to study aortic root/ascending aneurysm tissue from Fbn1C1041G/+ (MFS) mice and healthy controls, identifying all aortic cell types. A distinct cluster of transcriptomically modulated SMCs (modSMCs) was identified in adult Fbn1C1041G/+ mouse aortic aneurysm tissue only. Comparison with atherosclerotic aortic data (ApoE-/- mice) revealed similar patterns of SMC modulation but identified an MFS-specific gene signature, including plasminogen activator inhibitor-1 (Serpine1) and Kruppel-like factor 4 (Klf4). We identified 481 differentially expressed genes between modSMC and SMC subsets; functional annotation highlighted extracellular matrix modulation, collagen synthesis, adhesion, and proliferation. Pseudotime trajectory analysis of Fbn1C1041G/+ SMC/modSMC transcriptomes identified genes activated differentially throughout the course of phenotype modulation. While modSMCs were not present in young Fbn1C1041G/+ mouse aortas despite small aortic aneurysm, multiple early modSMCs marker genes were enriched, suggesting activation of phenotype modulation. modSMCs were not found in nondilated adult Fbn1C1041G/+ descending thoracic aortas. Single-cell RNA sequencing from human MFS aortic root aneurysm tissue confirmed analogous SMC modulation in clinical disease. Enhanced expression of TGF-β (transforming growth factor beta)-responsive genes correlated with SMC modulation in mouse and human data sets.

CONCLUSIONS

Dynamic SMC phenotype modulation promotes extracellular matrix substrate modulation and aortic aneurysm progression in MFS. We characterize the disease-specific signature of modSMCs and provide temporal, transcriptomic context to the current understanding of the role TGF-β plays in MFS aortopathy. Collectively, single-cell RNA sequencing implicates TGF-β signaling and Klf4 overexpression as potential upstream drivers of SMC modulation.