Features Of Marfan Syndrome Research Articles

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

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

Genetic mutation and aqueous humor metabolites alterations in a family with Marfan syndrome

This study used four generations of a Chinese family to reveal the genetic etiology and ocular manifestation pathogenesis of Marfan syndrome (MFS) through whole genome sequencing (WGS) and metabolomics analysis. In the study, we explored the pathogenic gene variant and aqueous humor (AH) metabolites alterations of MFS. Using WGS, a novel heterozygous variant (NM_000138: c.G4192A, p.D1398 N) in the fibrilin-1 (FBN1) gene was identified. This variant was co-segregated with the phenotype and considered “deleterious” and highly conserved during evolution. The p.D1398 N variant is located in a cbEGF-like domain and predicted to lead to a new splice site, which might result in structural and functional changes to the FBN1 protein. FBN1 is highly expressed in the mouse cornea, conjunctiva and lens capsule, which highlights the important role of FBN1 in eyeball development. AH metabolomics analysis identified eight differentially expressed metabolites, including 3-hydroxyphenylacetic acid, 4-pyridoxic acid, aminoadipic acid, azelaic acid, chlordiazepoxide, niacinamide, ribose, 1,5-bisphosphate and se-methylselenocysteine, associated with relevant metabolic pathways likely involved in the pathogenesis of ocular symptoms in MFS. Our analysis extends the existing spectrum of disease-causing mutations and reveals metabolites information related to the ophthalmic features of MFS. This may provide a new sight and a basis for the diagnosis and mechanism of MFS.

Pregnancy-related cardiovascular events in marfan syndrome

Abstract Background Some studies have suggested an increased risk of aortic dissection (AoDis) during pregnancy and higher rate of cardiovascular (CV) events on the long-term in Marfan syndrome (MFS) patients. Purpose To analyse the rate of CV events during pregnancy and follow up in our cohort of MFS patients. Methods We prospectively collected data of a cohort of women with MFS that attended our dedicated clinic between the years 2000-2021. This included demographics, clinical characteristics and pregnancy. CV events were defined as AoDis, urgent AoSurg or CV death. Patients with a previous event before the first pregnancy were excluded. Results We identified 148 women with a mean age at last follow up of 40±16 years and a mean follow up of 11 years (IQR 25-75: 4-17 years). Sixty-nine patients fell pregnant (130 pregnancies, median 2, range 1-4 pregnancies, age at delivery 29±5y) and 79 were never pregnant. Amongst the 69 ever pregnant patients, 2 patients had a type A AoDis during pregnancy (one was unaware of the MFS diagnosis; the other was under follow up with a pre-pregnancy aortic root of 34mm/Z-score 1.5 and at third trimester of 36 mm/Z-score 2.2). No maternal deaths were recorded. Pregnancy related rate of CV events was 2.9% and 1.5% in women with known MFS diagnosis before pregnancy. Ever-pregnant patients were older at diagnosis (32±17y vs 20±14y, p<0,001) and at the end of follow up (49±14y vs 33±13, p<0,001) compared to never-pregnant patients. Ectopia lentis was significantly higher in never-pregnant patients (45.3% vs 25%, p=0.03). There were no statistically significant differences in time of follow up or other clinical features of MFS. Only 36% of the ever-pregnant cohort were diagnosed before pregnancy. During follow up, 14 patients from the ever-pregnant group and 16 patients from the never-pregnant group underwent prophylactic AoSurg (p=0,72). Never-pregnant patients were younger at age of elective AoSurg (35±14y vs 45±13y, p=0.031). Eleven (7.4%) patients experienced a CV event (7 type A and 4 type B AoDis), 7 in the ever-pregnant group and 4 in the never pregnant group (p=0.09). Age at CV event was similar in the ever-pregnant and never-pregnant groups (48±11y vs 40±8y, p=0.26) In the ever-pregnant group, 3 patients experienced ³2 CV events during follow up compared to none in the never-pregnant group (p=0.1). Conclusion In our cohort of ever pregnant MFS patients, 2.9% of patients experienced a pregnancy related CV event. On the long term, never-pregnant patients were younger at age of elective AoSurg but there were no differences between the groups in prophylactic AoSurg or CV events.

Abstract 15521: Wnt Signaling Inhibition Prevents Postnatal Inflammation and Disease Progression in Congenital Myxomatous Valve Disease

Introduction: Myxomatous valve disease (MVD) is the most common cause of mitral regurgitation, leading to cardiac dysfunction and heart failure. MVD in a mouse model of Marfan syndrome (MFS) includes valve leaflet thickening and increased immune cell infiltration. However, the underlying mechanisms by which immune cells are recruited in MFS valves remain undefined. Hypothesis: Inhibition of Wnt signaling prevents MVD progression in MFS valves. Methods: Mice with the Fibrillin 1 variant Fbn1 C1039G/+ recapitulate histopathological features of MFS and Wnt signaling activity was detected in TCF/Lef-lacZ reporter mice. Single-cell RNA sequencing was performed from mitral valves of WT and Fbn1 C1039G/+ mice at 1 month-of-age. Inhibition of Wnt signaling was achieved by conditional induction of Wnt inhibitor Dkk1 in valve interstitial cells of Fbn1 C1039G/+ ; Periostin-Cre; tetO-Dkk1; R26-rtTA mice. Dietary doxycycline was administered for 1 month beginning with MVD initiation (1-month-old) or MVD progression (2-month-old). Histological evaluation and immunofluorescence for immune cells were performed. Results: Wnt signaling pathway gene expression is activated early in mitral valve disease progression, prior to immune cell infiltration in Fbn1 C1039G/+ mice. Single cell transcriptomics revealed similar mitral valve cell heterogeneity between WT and Fbn1 C1039G/+ mice at 1 month-of-age. Wnt ligands and responsive genes were predominantly increased in valve interstitial cells and valve endothelial cells of Fbn1 C1039G/+ mice. Inhibition of Wnt signaling by Dkk1 induction at 1 month-of-age prevented the initiation of MVD as indicated by reduced valve leaflet thickness with decreased CD45+ leukocytes and CCR2+ immune cells in Fbn1 C1039G/+ mice. However, later Wnt inhibition starting at 2 months when inflammation and myxomatous changes are occurring did not prevent the progression of MVD. Conclusions: Wnt signaling is involved in the initiation of mitral valve abnormalities and inflammation, but is not responsible for valve disease progression once it has been initiated. Thus, Wnt signaling inhibition prevents initiation of congenital MVD, which provides a promising therapeutic target for the early treatment of congenital MVD.

Abstract P1012: Wnt Signaling Is Required For Myxomatous Valve Disease In A Mouse Model Of Marfan Syndrome

Introduction: Myxomatous valve disease (MVD) is the most common cause of mitral regurgitation, characterized by valve leaflet thickening and progressive valve degeneration, leading to impaired cardiac function and heart failure. MVD in a mouse model of Marfan syndrome (MFS) includes valve leaflet thickening and increased immune cell infiltration. However, the underlying mechanisms by which immune cells are recruited in MFS valves remain undefined. Hypothesis: Inhibition of Wnt signaling prevents immune cell recruitment and MVD progression in MFS valves. Methods: Mice with the mutation of Fibrillin 1 ( Fbn1 C1039G/+ ) recapitulate histopathological features of MFS and Wnt signaling activity was detected in TCF/Lef-lacZ reporter mice. The expression level of C-C motif chemokine ligand 2 (CCL2) was detected in Fbn1 C1039G/+ mice by qPCR and RNAscope. Inhibition of Wnt signaling was achieved by conditional induction of the soluble Wnt inhibitor Dkk1 in periostin-expressing valve interstitial cells of Periostin-Cre; tetO-Dkk1; R26rtTA; TCF/Lef-lacZ; Fbn1 C1039G/+ mice. Dietary doxycycline was administered for one month beginning with MVD initiation (1-month-old) or MVD progression (2-month-old). Histological evaluation and immunofluorescence for immune cells were performed. Results: Wnt signaling as detected by TCF/Lef-lacZ reporters and CCL2 expression were upregulated early in mitral valve disease progression, prior to immune cell infiltration in Fbn1 C1039G/+ mice. Inhibition of Wnt signaling by Dkk1 induction at 1-month of age prevented the induction of myxomatous mitral valve disease, indicated by reduced valve leaflet thickness with decreased CD45+ leukocytes and CCR2+ immune cells in Fbn1 C1039G/+ mice. However, later Wnt inhibition starting at 2 months when inflammation and myxomatous changes are occurring did not prevent the progression of myxomatous mitral valve disease. Conclusions: Wnt signaling is involved in the initiation of mitral valve abnormalities and inflammation, but is not responsible for valve disease progression once it has been initiated.

Pregnancy-associated aortopathy and sudden postpartum death

A 39-year-old woman who had undergone an uncomplicated elective cesarean section for a low-lying placenta collapsed and died the following day. At autopsy, there was dissection of an aneurysmally-dilated thoracic aorta with 400 mls of fluid and clotted blood in the pericardial sac. There were no features of Marfan syndrome or other connective tissue disorders. Histology revealed thinning of the aortic wall with fragmentation of elastic fibers and no inflammation. Vessels elsewhere were normal. This case demonstrates a rare complication of pregnancy that may not present until after delivery with unexpected collapse and sudden death. Predisposing factors include an increased cardiac output, reduction in systemic vascular resistance, an increase in left ventricular muscle mass, and alterations in serum progesterone and estrogen levels which may cause structural changes to the aortic wall. The possibility of syndromic and familial connective tissue disorders should also be considered.

A phenotypic screen of Marfan syndrome iPSC-derived vascular smooth muscle cells uncovers GSK3β as a new target.

Marfan syndrome (MFS) is a rare connective tissue disorder caused by mutations in FBN1. Patients with MFS notably suffer from aortic aneurysm and dissection. Despite considerable effort, animal models have proven to be poorly predictive for therapeutic intervention in human aortic disease. Patient-derived induced pluripotent stem cells can be differentiated into vascular smooth muscle cells (VSMCs) and recapitulate major features of MFS. We have screened 1,022 small molecules in our invitro model, exploiting the highly proteolytic nature of MFS VSMCs, and identified 36 effective compounds. Further analysis identified GSK3β as a recurring target in the compound screen. GSK3β inhibition/knockdown did not ameliorate the proliferation defect in MFS-VSMCs but improved MFS-VSMC proteolysis and apoptosis and partially rescued fibrillin-1 deposition. To conclude, we have identified GSK3β as a novel target for MFS, forming the foundation for future work in MFS and other aortic diseases.

Abstract P1112: Inhibition Of Wnt Signaling Protects Against Myxomatous Valve Disease In A Mouse Model Of Marfan Syndrome

Introduction: Myxomatous valve disease (MVD) is the most common cause of mitral regurgitation, characterized by valve leaflet thickening and progressive valve degeneration, leading to impaired cardiac function and heart failure. MVD in a mouse model of Marfan syndrome (MFS) includes valve leaflet thickening and increased immune cell infiltration. However, the underlying mechanisms by which immune cells are recruited in MFS valves remain undefined. Hypothesis: Inhibition of Wnt signaling prevents immune cell recruitment and MVD progression in MFS valves. Methods: Mice with the mutation of Fibrillin 1 ( Fbn1 C1039G/+ ) recapitulate histopathological features of MFS and Wnt signaling activity was detected in TCF/Lef-lacZ reporter mice. Inhibition of Wnt signaling was achieved by conditional induction of the soluble Wnt inhibitor Dkk1 in periostin-expressing valve interstitial cells of Periostin-Cre; tetO-Dkk1; R26rtTA; TCF/Lef-lacZ; Fbn1 C1039G/+ mice. Dietary doxycycline was administered for one month beginning with MVD initiation (1-month-old) or MVD progression (2-month-old). Histological evaluation and immunofluorescence for immune cells were performed. Results: Wnt signaling as detected by TCF/Lef-reporters is activated early in mitral valve disease progression, prior to immune cell infiltration in Fbn1 C1039G/+ mice. Inhibition of Wnt signaling by Dkk1 induction at 1-month of age reduced valve leaflet thickness with decreased CD45+ leukocytes in Fbn1 C1039G/+ mice. However, later Wnt inhibition starting at 2 months did not alter valve leaflet thickness. Conclusions: Inhibition of early Wnt signaling ameliorates myxomatous valve degeneration and immune cell infiltration previously demonstrated to be required for progression of MVD.

Exome Sequencing Identifies Genetic Variants Associated with Extreme Manifestations of the Cardiovascular Phenotype in Marfan Syndrome.

Marfan Syndrome (MFS) is an autosomal dominant condition caused by variants in the fibrillin-1 (FBN1) gene. Cardinal features of MFS include ectopia lentis (EL), musculoskeletal features and aortic root aneurysm and dissection. Although dissection of the ascending aorta is the main cause of mortality in MFS, the clinical course differs considerably in age of onset and severity, even among individuals who share the same causative variant, suggesting the existence of additional genetic variants that modify the severity of the cardiovascular phenotype in MFS. We recruited MFS patients and classified them into severe (n = 8) or mild aortic phenotype (n = 14) according to age of presentation of the first aorta-related incident. We used Exome Sequencing to identify the genetic variants associated with the severity of aortic manifestations and we performed linkage analysis where suitable. We found five genes associated with severe aortic phenotype and three genes that could be protective for this phenotype in MFS. These genes regulate components of the extracellular matrix, TGFβ pathway and other signaling pathways that are involved in the maintenance of the ECM or angiogenesis. Further studies will be required to understand the functional effect of these variants and explore novel, personalized risk management and, potentially, therapies for these patients.

Abstract 122: Pharmacological Inhibition Of Macrophage Infiltration Prevents Myxomatous Valve Degeneration In Marfan Syndrome

Introduction: Myxomatous valve degeneration (MVD) is the most common cause of mitral regurgitation, characterized by valve leaflet thickening and progressive valve degeneration, leading to impaired cardiac function and heart failure. Currently, there is no medical therapy for the treatment of MVD. MVD in a mouse model of Marfan syndrome (MFS) is characterized leaflet thickening and increased macrophage infiltration, which are reduced with loss of C-C chemokine receptor type 2 (CCR2). However, the specific contributions of macrophages to pathological extracellular matrix (ECM) remodeling and underlying mechanisms are unknown. Hypothesis: Inhibition of macrophage infiltration by a CCR2 inhibitor blocks ECM abnormalities and MVD progression in mitral valves of MFS mice by suppressing the response to cytokine/chemokines. Methods: Mice with the mutation of Fibrillin 1 (Fbn1 C1039G/+ ) recapitulate histopathological features of MFS. Here, we tested the efficacy of a selective CCR2 antagonist RS504393 in the valves of MFS mice in the initiation (1-month-old) and the progression (2-month-old) of MVD, respectively. MFS mice were intraperitoneally injected with RS504393 at 2 mg/kg/d for 30 days. Histological evaluation and immunofluorescence for macrophages and ECM were performed. RNAseq was performed in mitral valves from 2-month old Fbn1 C1039G/+ mice with CCR2 knockout (CCR2 RFP/RFP ). Results: MFS valves revealed ECM abnormalities characterized by collagen fragmentation and proteoglycan accumulation. RS504393 treatment reduced infiltrating macrophages (MHCII+, CCR2+) in myxomatous valves. Remarkably, RS504393 was protective against both the initiation and the progression of MVD, detected by decreased mitral valve thickness and prevention of pathological ECM remodeling in MFS mice. RNAseq data confirmed increased leukocyte activation involved in immune response and abnormal extracellular matrix remodeling in MFS valves. CCR2 deficiency blocked macrophage infiltration and inhibited the response to cytokines in Fbn1 C1039G/+ valves. Conclusions: Our results show that macrophage infiltration is critical for progressive MVD. Moreover, CCR2 inhibition ameliorates MVD progression by preventing immune response. Thus, the CCR2 inhibitor RS504393 is a potential pharmacological candidate to treat MVD in MFS.

CHARACTERISTICS OF THE FOVEAL MICROVASCULATURE IN CHILDREN WITH MARFAN SYNDROME: An Optical Coherence Tomography Angiography Study.

To investigate the characteristics of foveal microvasculature in children with Marfan syndrome (MFS). Ninety eyes from 45 MFS patients and 76 eyes from 38 healthy individuals of age-matched, sex-matched, and axial length-matched were enrolled. Characteristics of the superficial capillary plexus including the vessel density, perfusion density, and foveal avascular zone were analyzed by optical coherence tomography angiography. The vessel density and the circularity index of the foveal avascular zone were significantly decreased in the MFS group compared with the controls (P = 0.017 and P = 0.004 respectively). In MFS group, the central vessel density (P = 0.003) and perfusion density (P = 0.001) were negatively correlated with the best-corrected visual acuity. The foveal avascular zone area was correlated with the aortic diameters (P = 0.001) and the paratemporal perfusion density was correlated with the ejection fraction (P = 0.003). Moreover, the paratemporal perfusion density and the circularity index of foveal avascular zone were found to be correlated with the aortic Z-score (P < 0.001 and P = 0.003 respectively). Retinal microvascular decrease and its correlation with best-corrected visual acuity and cardiac functions were observed in the MFS group. The optical coherence tomography angiography may help to characterize the underlying pathophysiology features of MFS and enable early detection and prevention of vascular changes in MFS.

Marfan syndrome associated with type 1 diabetes and autoimmune thyroiditis in a 27 years old female patient - Case presentation

Abstract Introduction: Marfan syndrome (MFS) is a genetically determined connective tissue disorder caused by a mutation in the FBN1 gene, located on chromosome 1, which regulates the production of the glycoprotein Fibrillin 1. This results in different connective tissue diseases, especially cardiovascular involvement. Objective: The aim of our presentation is the description of a case in which type 1 autoimmune diabetes and thyreoiditis coexists in a previously undiagnosed patient with MFS. Case presentation: A 27-years-old female patient presented to the emergency department with a 6 months long polyuria-polydipsia syndrome, with weight loss of -10kg. The onset of diabetes manifested with severe ketoacidosis (blood glucose=674 mg/dl, pH=7,036, urinary ketone bodies=159 mg/dl). Pathological laboratory findings include C-peptide=212 ng/ml, anti glutamic acid decarboxylase (GAD) = 5,1UI/ml, ATPO=558 UI/ml. Clinical features of MFS could be recognised, like dolicocephalic face with enophthalmus, height: 184 cm, weight: 40 kg with a BMI of 11,81 kg/m2 respectively 50 kg and 14,77 kg/m2 before weight loss; long limbs, arachnodactyly, kyphoscoliosis, mitral systolic murmur. Imaging procedures showed atrial septal defect with a 6 mm bidirectional shunt, the ascending aorta, the trunk and the aortic isthmus were dilated, mitral valve prolapse, tricuspid valve insufficiency and dilatation of the right heart cavities, interatrial septal aneurysm and pulmonary hypertension. The ECG showed a right branch block. Ophthalmologic examination confirms the lens subluxation. Discussion: The etiology of diabetes and thyroiditis has proven to be autoimmune. With the introduction of base-bolus insulin therapy glycemic control was obtained and beta-blocker treatment was started for the cardiac involvement. Summary: This particular case is unique due to the fact that associates two serious lifelong diseases. MFS should be considered on the basis of morphological characteristics, which requires further investigation due to its serious long term complications.

Pharmacological Inhibition of Macrophage Infiltration Prevents Myxomatous Valve Degeneration in Marfan Syndrome

Background Myxomatous valve degeneration (MVD) is the most common cause of mitral regurgitation, characterized by valve leaflet thickening and progressive valve degeneration, leading to impaired cardiac function and heart failure. MVD in a mouse model of Marfan syndrome (MFS) is characterized leaflet thickening and increased macrophage infiltration which are reduced with loss of C-C chemokine receptor type 2 (CCR2). However, the specific contributions of macrophages to pathological extracellular matrix (ECM) remodeling and the underlying mechanisms are unknown. Methods Mice with the mutation of Fibrillin 1 (Fbn1C1039G/+) recapitulate histopathological features of MFS. ECM remodeling in mitral valves was assessed by detecting collagen and proteoglycan in Fbn1C1039G/+; CCR2RFP/RFP mice. Here, we tested the efficacy of a selective CCR2 antagonist RS504393 in the valves of MFS model in the initiation (1-month-old) and the progression (2-month-old) of MVD, respectively. MFS mice were intraperitoneally injected with RS504393 at 2 mg/kg/d for 1 month. Histological evaluation and immunofluorescence for macrophages and ECM were performed. Results MFS valves revealed ECM abnormalities characterized by collagen fragmentation and proteoglycan accumulation. Deficiency of CCR2 inhibited ECM abnormalities in MFS mitral valves. RS504393 treatment reduced infiltrating macrophages (MHCII+, CCR2+) in myxomatous valves. Remarkably, RS504393 was protective against both the initiation and the progression of MVD, detected by decreased mitral valve thickness and prevented pathological ECM remodeling in MFS mice. Conclusion Our results suggest the deficiency of CCR2 inhibits macrophage infiltration and abnormal ECM remodeling. In addition, the CCR2 inhbitor RS504393 is a potential pharmacological candidate to treat MVD in MFS.

Semi-automatic quantification of aortic root progressive dilation by automatic co-registration of computed tomography angiograms: a preliminary comparison with manual assessment in Marfan patients

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Spanish Ministry of Science, Innovation and Universities Instituto de Salud Carlos III Background. Dilation of the aortic root is a key feature of Marfan syndrome and it is related to the occurrence of aortic events and death. On top of maximum diameter, rapid annual growth rate is suggested by guidelines for indication of aortic root replacement. Current gold-standard for aortic root diameter assessment is manual quantification on multiplanar reformatted 3D computed tomography (CT) or magnetic resonance angiogram. However, inter- and intra-observer reproducibility are limited and different measurement methods, i.e. cusp-to-cusp and cusp-to-commissure, may be used in different clinical centres, leading to difficulties in the clinical assessment of progressive dilation. Purpose. We aimed to test whether aortic root growth rate during follow-up can be reliably quantified by semi-automatic co-registration of two CT angiograms. Methods. Seven Marfan syndrome patients, free from previous aortic surgery, with a total of 11 pairs of CT were identified. Manual assessment of six aortic root diameters (right-non coronary -RN- , right-left -RL- and left-non coronary -LN- cusp-to-cusp and R, L and N cusp-to-commissure) was obtained from all CTs by an experienced researcher blind to semi-automatic results. The thoracic aorta and the outflow tract were semi-automatically segmented in the baseline CT and commissure and cusps were manually located. A 10 mm-thick region of interest containing the aortic wall was automatically generated from segmentation boundary. Co-registration was obtained with three, fully-automatic steps. Firstly, baseline and follow-up CT scans were aligned by means of a rigid registration. Then, scans were co-registered with multi-resolution affine followed by b-spline non-rigid registrations based on mutual information metric. The transformation pertaining to the location of baseline commissure and cusps points was used to locate the same points in the follow-up scan (Fig. 1 top). Results. Follow-up duration was 35 ± 22 (range 12-70.3) months. Automatic quantification of diameter growth during the follow-up was obtained in 62 out of 66 (94%) diameter comparisons. High Pearson correlation coefficients (R) and ICC were found between manual and semi-automatic assessment of growth rate, both for cusp-to-cusp and cusp-to-commissure diameters: R = 0.727 and ICC = 0.678 for RN; R = 0.822 and ICC = 0.602 for RL; R = 0.648 and ICC = 0.668 for LN; R = 0.726 and ICC = 0.711 for R; R = 0.911 and ICC = 0.895 for L and R = 0.553 and ICC = 0.482 for N. Scatter and Bland-Altman plots for all growth rates (Fig. 1) confirmed very good correlation (R = 0.810) but a slight tendency (R=-0.270) for underestimation at high growth rate. No correlation was found between follow-up duration and difference between techniques (R = 0.06). Conclusions. Semi-automatic quantification of aortic root growth rate by co-registration of pairs of CT angiograms is feasible for follow-up as short as one year. Larger studies are needed to confirm these preliminary data. Abstract Figure. CT measurements. Automatic vs manual.

Clinically relevant variants in a large cohort of Indian patients with Marfan syndrome and related disorders identified by next-generation sequencing

Marfan syndrome and related disorders are a group of heritable connective tissue disorders and share many clinical features that involve cardiovascular, skeletal, craniofacial, ocular, and cutaneous abnormalities. The majority of affected individuals have aortopathies associated with early mortality and morbidity. Implementation of targeted gene panel next-generation sequencing in these individuals is a powerful tool to obtain a genetic diagnosis. Here, we report on clinical and genetic spectrum of 53 families from India with a total of 83 patients who had a clinical diagnosis suggestive of Marfan syndrome or related disorders. We obtained a molecular diagnosis in 45/53 (85%) index patients, in which 36/53 (68%) had rare variants in FBN1 (Marfan syndrome; 63 patients in total), seven (13.3%) in TGFBR1/TGFBR2 (Loeys–Dietz syndrome; nine patients in total) and two patients (3.7%) in SKI (Shprintzen–Goldberg syndrome). 21 of 41 rare variants (51.2%) were novel. We did not detect a disease-associated variant in 8 (15%) index patients, and none of them met the Ghent Marfan diagnostic criteria. We found the homozygous FBN1 variant p.(Arg954His) in a boy with typical features of Marfan syndrome. Our study is the first reporting on the spectrum of variants in FBN1, TGFBR1, TGFBR2, and SKI in Indian individuals.

Specific miRNA and Gene Deregulation Characterize the Increased Angiogenic Remodeling of Thoracic Aneurysmatic Aortopathy in Marfan Syndrome.

Marfan syndrome (MFS) is a connective tissue disease caused by mutations in the FBN1 gene, leading to alterations in the extracellular matrix microfibril assembly and the early formation of thoracic aorta aneurysms (TAAs). Non-genetic TAAs share many clinico-pathological aspects with MFS and deregulation of some microRNAs (miRNAs) has been demonstrated to be involved in the progression of TAA. In this study, 40 patients undergoing elective ascending aorta surgery were enrolled to compare TAA histomorphological features, miRNA profile and related target genes in order to find specific alterations that may explain the earlier and more severe clinical outcomes in MFS patients. Histomorphological, ultrastructural and in vitro studies were performed in order to compare aortic wall features of MFS and non-MFS TAA. MFS displayed greater glycosaminoglycan accumulation and loss/fragmentation of elastic fibers compared to non-MFS TAA. Immunohistochemistry revealed increased CD133+ angiogenic remodeling, greater MMP-2 expression, inflammation and smooth muscle cell (SMC) turnover in MFS TAA. Cultured SMCs from MFS confirmed higher turnover and α-smooth muscle actin expression compared with non-MFS TAA. Moreover, twenty-five miRNAs, including miR-26a, miR-29, miR-143 and miR-145, were found to be downregulated and only miR-632 was upregulated in MFS TAA in vivo. Bioinformatics analysis revealed that some deregulated miRNAs in MFS TAA are implicated in cell proliferation, extracellular matrix structure/function and TGFβ signaling. Finally, gene analysis showed 28 upregulated and seven downregulated genes in MFS TAA, some of them belonging to the CDH1/APC and CCNA2/TP53 signaling pathways. Specific miRNA and gene deregulation characterized the aortopathy of MFS and this was associated with increased angiogenic remodeling, likely favoring the early and more severe clinical outcomes, compared to non-MFS TAA. Our findings provide new insights concerning the pathogenetic mechanisms of MFS TAA; further investigation is needed to confirm if these newly identified specific deregulated miRNAs may represent potential therapeutic targets to counteract the rapid progression of MFS aortopathy.

Classifying Ectopia Lentis in Marfan Syndrome into Five Grades of Increasing Severity.

Purpose: To describe a five-grade classification of ectopia lentis in Marfan syndrome (MFS) and to evaluate the positive predictive value of the early grades of ectopia lentis. Methods: We prospectively included MFS patients and their healthy relatives. The anterior segment examination was classified into grades 0 to 5, and we studied the sensitivity, specificity, and positive predictive value of ectopia lentis in this classification. Results: Seventy-four MFS patients and thirty-six healthy controls were examined. In the MFS group, grades 1, 2, 3, and 4 were present in 15, 24, 17, and 7 patients, respectively, whereas 11 patients in this group did not present ectopia lentis. In the control group, grades 0 and 1 were observed in 30 and 6 individuals, respectively. Sensitivity to ectopia lentis of at least grade 2 was 64.9%, with 100% specificity, whereas sensitivity to ectopia lentis of at least grade 1 was 85.1%, with 83.3% specificity. The positive predictive value of ectopia lentis that was greater than or equal to grade 2 was 100%, whereas that of ectopia lentis greater than or equal to grade 1 was 91.3%. Conclusions: High positive predictive values s were found to be associated with grades 2 and higher of the five-grade classification of ectopia lentis. This classification should help to harmonize clinical practices for this major feature of MFS.

The natural history of type B aortic dissection in patients with PRKG1 mutation c.530G>A (p.Arg177Gln)

ObjectiveThe c.530G>A (p.Arg177Gln) mutation in PRKG1 has been shown to be associated with thoracic aortic aneurysms and dissections. This rare mutation accounts for an estimated 1% of nonsyndromic heritable thoracic aortic disease. We sought to describe the clinical presentation of type B aortic dissection (TBAD), management, and outcomes in patients with this mutation. MethodsThis is a descriptive multi-institutional retrospective study of patients from six families with the PRKG1 mutation. Patients with TBAD were selected for analysis. Demographics, family histories, TBAD management, and outcomes were reviewed. ResultsOf the 29 individuals diagnosed with the PRKG1 mutation, 12 (41.3%) had TBAD (50% male, TBAD median age: 31 years [range, 16-58 years], median follow-up: 6 years [range, 3-15 years] after TBAD). All had a family history of aortic dissections and none had features of Marfan syndrome. The median size of the descending thoracic aorta (DTA) at TBAD was 4.1 cm (range, 3.8-5 cm). Most cases (9 acute TBAD, 1 incidental TBAD diagnosis during screening) were managed medically. One case had open DTA repair the acute phase. Repair for dissection-related aneurysmal degeneration was performed in seven cases (58.3%) in the chronic phase at a median of 2 years (range, 1-8 years) after TBAD. In four cases (33.3%), the DTA remained stable in size over a range of 1 to 7 years after TBAD. Type A aortic dissection subsequent to TBAD occurred in three cases (25%). There were four (33.3%) deaths in the series, all aortic related at a median age of 24 years (range, 19-43 years). ConclusionsThe PRKG1 (p.Arg177Gln) mutation although rare is associated with nonsyndromic TBAD in young and middle-aged patients. Workup for this gene mutation should be included as part of the workup for TBAD etiology in relatively young patients and those with familial history of aortic dissections. Once diagnosed, testing of first-degree family members is warranted. In all individuals with a PRKG1 mutation, close follow-up for aortic root dilatation and hypertension control is essential to reduce the risk of type A or type B aortic dissection, and in cases of TBAD, to decrease the risk of dissection-related aneurysmal degeneration.

Marfan Syndrome with Varieties of Clinical Features

Marfan Syndrome is an autosomal dominant disorder caused by mutation in the extracellular matrix protein fibrilin-1 gene located on chromosome 15. It has variable range of expression.We describe a case of a 12 year aged girl with positive family history including lean and thin body stature, skin striae, joint hyper mobility, high arched palate, mal occlusion of teeth, pectus excavatum, winging of scapula, scoliosis of back bone, total arm span more than total body height (1.11:1), lower segment greater than upper segment (1.40:1), severe form of mitral valve prolapse and aortic root dilatation. There are a lot of features of Marfan Syndrome in our single patient which is rare in earlier available case reports.J MEDICINE Jan 2018; 19 (1) : 58-62

Differences in manifestations of Marfan syndrome, Ehlers-Danlos syndrome, and Loeys-Dietz syndrome.

Many different heritable connective tissue disorders (HCTD) have been described over the past decades. These syndromes often affect the connective tissue of various organ systems, including heart, blood vessels, skin, joints, bone, eyes, and lungs. The discovery of these HCTD was followed by the identification of mutations in a wide range of genes encoding structural proteins, modifying enzymes, or components of the TGFβ-signaling pathway. Three typical examples of HCTD are Marfan syndrome (MFS), Ehlers-Danlos syndrome (EDS), and Loeys-Dietz syndrome (LDS). These syndromes show some degree of phenotypical overlap of cardiovascular, skeletal, and cutaneous features. MFS is typically characterized by cardiovascular, ocular, and skeletal manifestations and is caused by heterozygous mutations in FBN1, coding for the extracellular matrix (ECM) protein fibrillin-1. The most common cardiovascular phenotype involves aortic aneurysm and dissection at the sinuses of Valsalva. LDS is caused by mutations in TGBR1/2, SMAD2/3, or TGFB2/3, all coding for components of the TGFβ-signaling pathway. LDS can be distinguished from MFS by the unique presence of hypertelorism, bifid uvula or cleft palate, and widespread aortic and arterial aneurysm and tortuosity. Compared to MFS, LDS cardiovascular manifestations tend to be more severe. In contrast, no association is reported between LDS and the presence of ectopia lentis, a key distinguishing feature of MFS. Overlapping features between MFS and LDS include scoliosis, pes planus, anterior chest deformity, spontaneous pneumothorax, and dural ectasia. EDS refers to a group of clinically and genetically heterogeneous connective tissue disorders and all subtypes are characterized by variable abnormalities of skin, ligaments and joints, blood vessels, and internal organs. Typical presenting features include joint hypermobility, skin hyperextensibility, and tissue fragility. Up to one quarter of the EDS patients show aortic aneurysmal disease. The latest EDS nosology distinguishes 13 subtypes. Many phenotypic features show overlap between the different subtypes, which makes the clinical diagnosis rather difficult and highlights the importance of molecular diagnostic confirmation.