Abstract
Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body. The majority of FMD patients are women. Although ...a variety of genetic, mechanical, and hormonal factors play a role in the pathogenesis of FMD, overall, its cause remains poorly understood. It is probable that the pathogenesis of FMD is linked to a combination of genetic and environmental factors. Extensive studies have correlated the arterial lesions of FMD to histopathological findings of arterial fibrosis, cellular hyperplasia, and distortion of the abnormal architecture of the arterial wall. More recently, the vascular phenotype of lesions associated with FMD has been expanded to include arterial aneurysms, dissections, and tortuosity. However, in the absence of a string-of-beads or focal stenosis, these lesions do not suffice to establish the diagnosis. While FMD most commonly involves renal and cerebrovascular arteries, involvement of most arteries throughout the body has been reported. Increasing evidence highlights that FMD is a systemic arterial disease and that subclinical alterations can be found in non-affected arterial segments. Recent significant progress in FMD-related research has led to improve our understanding of the disease’s clinical manifestations, natural history, epidemiology, and genetics. Ongoing work continues to focus on FMD genetics and proteomics, physiological effects of FMD on cardiovascular structure and function, and novel imaging modalities and blood-based biomarkers that can be used to identify subclinical FMD. It is also hoped that the next decade will bring the development of multi-centred and potentially international clinical trials to provide comparative effectiveness data to inform the optimal management of patients with FMD.
Graphical Abstract
Current understanding of FMD.
Current understanding of FMD.
Skeletal muscle has the ability to achieve rapid repair in response to injury or disease. Many individuals with Marfan syndrome (MFS), caused by a deficiency of extracellular fibrillin-1, exhibit ...myopathy and often are unable to increase muscle mass despite physical exercise. Evidence suggests that selected manifestations of MFS reflect excessive signaling by transforming growth factor (TGF)-β (refs. 2,3). TGF-β is a known inhibitor of terminal differentiation of cultured myoblasts; however, the functional contribution of TGF-β signaling to disease pathogenesis in various inherited myopathic states in vivo remains unknown. Here we show that increased TGF-β activity leads to failed muscle regeneration in fibrillin-1-deficient mice. Systemic antagonism of TGF-β through administration of TGF-β-neutralizing antibody or the angiotensin II type 1 receptor blocker losartan normalizes muscle architecture, repair and function in vivo. Moreover, we show TGF-β-induced failure of muscle regeneration and a similar therapeutic response in a dystrophin-deficient mouse model of Duchenne muscular dystrophy.
NOTE: In the version of this article initially published, the same panels were inadvertently used to show negative pSmad2/3 and periostin staining in muscle of Fbn1C1039G/+ mice treated with TGF-β-neutralizing antibody in both the steady-state (Fig. 1a, right column, second and third rows, respectively) and muscle-regeneration (Fig. 1b, right column, third and fourth rows, respectively) experiments. In reality, these images only relate to the steady-state experiment (Fig. 1a). The intended images for Figure 1b are provided (red, pSmad2/3 staining; green, periostin staining). As both sets of images show negative staining in neutralizing antibody-treated Fbn1C1039G/+ mice, this does not alter any observations or conclusions discussed in the manuscript. The error has been corrected in the HTML and PDF versions of the article.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Background Loeys-Dietz syndrome (LDS) is a recently described genetic aortic aneurysm syndrome resulting from mutations in receptors for the cytokine transforming growth factor-β. Phenotypic features ...include a bifid uvula, hypertelorism, cleft palate, and generalized arterial tortuosity, but risk of thoracic aortic rupture and dissection is the principle focus of management and exceeds that of most known connective tissue disorders. Our surgical experience with LDS was reviewed to assess outcomes and develop guidelines for management of this aggressive disease. Methods We retrospectively reviewed medical records of all LDS patients from two institutions and obtained follow-up data from medical records and patient contacts. Results Clinical criteria and genotyping were used to identify 71 patients. Before surgical intervention, 6 patients (9%) died from aneurysm rupture or dissection, which occurred in several patients with aortic diameters of less than 4.5 cm and as early as 6 months of age. Thoracic aortic aneurysm surgery was performed in 14 children and 7 adults. Operations included valve-sparing root replacement (VSRR) in 13, Bentall procedure in 5, arch replacement in 2, and VSRR with arch replacement in 1. There were no deaths at the primary operation, although 3 patients died 2, 5, and 11 years after surgery from rupture of the descending thoracic (n = 2) or abdominal aorta (n = 1). Conclusions LDS is an aggressive aortic aneurysm disease with a propensity toward rupture and dissection at a younger age and smaller aortic diameters than in other connective tissue disorders, particularly in the ascending aorta. Early recognition of the phenotype, prophylactic intervention, and meticulous surveillance of the distal aorta and vascular tree are warranted for optimal management.
The importance of genetic testing for cardiomyopathies has increased in the last decade. However, in heart transplant patients with former cardiomyopathy, genetic testing in retrospect is not ...routinely performed. We hypothesize that the yield of genetic testing in this population is considerable, and will have a major impact for both patients and relatives.
Patients that underwent heart transplantation (HTx) between 1995 and 2020 and were still in follow-up, were offered genetic testing if the primary etiology was non-ischemic cardiomyopathy. Next generation sequencing (NGS) of known cardiomyopathy genes was performed and variants were classified as variant of unknown significance (class 3), likely pathogenic (class 4) or pathogenic (class 5) variant.
Of the 99 HTx patients in active follow-up, only 6 patients had a genetic diagnosis at the time of HTx. In this study, 31 selected patients with prior non-ischemic cardiomyopathy underwent genetic testing post HTx. 23/31 patients (74.2%) carried a variant that was classified as class 3 or higher. In 12/31 patients a class 4/5 variant (38.7%) was identified, and in 11/31 patients (35.5%) a class 3 variant. Class 5 Variants in TTN were the most prevalent (7/31), followed by class 5 variants in MYBPC3 (2/31). A positive family history was present in 21/31 (67.7%) and a second precipitating factor (e.g., alcohol abuse, pregnancy) was present in 17/31 patients (54.8%). Diagnostic yield of genetic testing was similar between patients with or without familial history and/or second hit. Through cascade screening 48 family members were screened for presence of a class 4/5 variant, of whom 19 (39.6%) were genotype positive, of whom 10 (52.6%) showed a cardiac phenotype. Appropriate follow-up was offered.
Genetic testing for cardiomyopathy genes established a molecular diagnosis in 38.7% of patients post HTx. These results highlight the importance of genetic testing in this population as it is still often overlooked in patients that already underwent HTx in the past. Genetic testing is highly recommended, independent of family history or second precipitating factors, as it might identify relatives at risk.
Thoracic aortic aneurysm (TAA) is a potentially life-threatening disorder with a strong genetic component. The number of genes implicated in TAA has increased exponentially over the last decade. ...Approximately 20% of patients with TAA have a positive family history. As most TAA remain asymptomatic for a long time, screening of at risk relatives is warranted to prevent complications. Existing international guidelines lack detailed instructions regarding genetic evaluation and family screening of TAA patients. We aimed to develop a consensus document to provide medical guidance for all health care professionals involved in the recognition, diagnosis and treatment of patients with thoracic aortic disease and their relatives.
A multidisciplinary panel of experts including cardiologists, cardiothoracic surgeons, clinical geneticists and general practitioners, convened to review and discuss the current literature, guidelines and clinical practice on genetic testing and family screening in TAA.
There is a lack of high-quality evidence in the literature. This consensus statement, based on the available literature and expert opinions, summarizes our recommendations in order to standardize and optimize the cardiogenetic care for patients and families with thoracic aortic disease. In particular, we provide criteria to identify those patients most likely to have a genetic predisposition, and discuss the preferred modality and frequency of screening in their relatives.
Age, family history, aortic size and syndromic features determine who is advised to have genetic testing as well as screening of first-degree relatives. There is a need for more prospective multicenter studies to optimize current recommendations.
A large family is described with gray platelet syndrome due to an autosomal dominant inheritance pattern related to a dominant-negative mutation in
GFI1B
. The mutation leads to a loss in gene ...repression during megakaryocyte development.
Platelets are formed through fragmentation of megakaryocytes that reside in the bone marrow.
1
,
2
Platelet alpha granules, which are by far the most abundant platelet organelles, store proteins that stimulate platelet adhesiveness, hemostasis, and wound healing.
3
,
4
The gray platelet syndrome is an inherited bleeding disorder characterized by defective production of alpha granules.
5
,
6
Patients with this syndrome have reduced numbers of larger-than-normal platelets, and on light microscopy these platelets have a typical gray appearance caused by the lack of alpha granules. For a final diagnosis, the lack of alpha granules must be confirmed by means of electron microscopy.
7
Clinically, . . .
In a large cohort of 373 pediatric patients with Marfan syndrome (MFS) with a severe cardiovascular phenotype, we explored the proportion of patients with MFS with a pathogenic FBN1 variant and ...analyzed whether the type/location of FBN1 variants was associated with specific clinical characteristics and response to treatment. Patients were recruited on the basis of the following criteria: aortic root z-score > 3, age 6 months to 25 years, no prior or planned surgery, and aortic root diameter < 5 cm.
Targeted resequencing and deletion/duplication testing of FBN1 and related genes were performed.
We identified (likely) pathogenic FBN1 variants in 91% of patients. Ectopia lentis was more frequent in patients with dominant-negative (DN) variants (61%) than in those with haploinsufficient variants (27%). For DN FBN1 variants, the prevalence of ectopia lentis was highest in the N-terminal region (84%) and lowest in the C-terminal region (17%). The association with a more severe cardiovascular phenotype was not restricted to DN variants in the neonatal FBN1 region (exon 25-33) but was also seen in the variants in exons 26 to 49. No difference in the therapeutic response was detected between genotypes.
Important novel genotype–phenotype associations involving both cardiovascular and extra-cardiovascular manifestations were identified, and existing ones were confirmed. These findings have implications for prognostic counseling of families with MFS.
Background The Pediatric Heart Network designed a clinical trial to compare aortic root growth and other short-term cardiovascular outcomes in children and young adults with Marfan syndrome ...randomized to receive atenolol or losartan. We report here the characteristics of the screened population and enrolled subjects. Methods and results Between 2007 and 2011, 21 clinical sites randomized 608 subjects, aged 6 months to 25 years who met the original Ghent criteria and had a body surface area–adjusted aortic root diameter z-score >3.0. The mean age at study entry was 11.2 years, 60% were male, and 25% were older teenagers and young adults. The median aortic root diameter z-score was 4.0. Aortic root diameter z-score did not vary with age. Mitral valve prolapse and mitral regurgitation were more common in females. Among those with a positive family history, 56% had a family member with aortic surgery, and 32% had a family member with a history of aortic dissection. Conclusions Baseline demographic, clinical, and anthropometric characteristics of the randomized cohort are representative of patients in this population with moderate to severe aortic root dilation. The high percentage of young subjects with relatives who have had aortic dissection or surgery illustrates the need for more definitive therapy; we expect that the results of the study and the wealth of systematic data collected will make an important contribution to the management of individuals with Marfan syndrome.
Aims In patients with Marfan syndrome and other type-1 fibrillinopathies, genetic testing is becoming more easily available, leading to the identification of mutations early in the course of the ...disease. This study evaluates the cardiovascular (CV) risk associated with the discovery of a fibrillin-1 (FBN1) mutation. Methods and results A total of 1013 probands with pathogenic FBN1 mutations were included, among whom 965 patients median age: 22 years (11–34), male gender 53% had data suitable for analysis. The percentage of patients with an ascending aortic (AA) dilatation increased steadily with increasing age and reached 96% (95% CI: 94–97%) by 60 years. The presence of aortic events (dissection or prophylactic surgery) was rare before 20 years and then increased progressively, reaching 74% (95% CI: 67–81%) by 60 years. Compared with women, men were at higher risk for AA dilatation ≤30 years: 57% (95% CI: 52–63) vs. 50% (95% CI: 45–55), P = 0.0076 and aortic events ≤30 years: 21% (95% CI: 17–26) vs. 11% (95% CI: 8–16), P < 0.0001; adjusted HR: 1.4 (1.1–1.8), P = 0.005. The prevalence of mitral valve (MV) prolapse ≤60 years: 77% (95% CI: 72–82) and MV regurgitation ≤60 years: 61% (95% CI: 53–69) also increased steadily with age, but surgery limited to the MV remained rare ≤60 years: 13% (95% CI: 8–21). No difference between genders was observed (for all P> 0.20). From 1985 to 2005 the prevalence of AA dilatation remained stable (P for trend = 0.88), whereas the percentage of patients with AA dissection significantly decreased (P for trend = 0.01). Conclusion The CV risk remains important in patients with an FBN1 gene mutation and is present throughout life, justifying regular aortic monitoring. Aortic dilatation or dissection should always trigger suspicion of a genetic background leading to thorough examination for extra-aortic features and comprehensive pedigree investigation.
Although historically Marfan syndrome (MFS) has always been considered as a condition caused by the deficiency of a structural extracellular matrix protein, fibrillin-1, the study of Marfan mouse ...models and Marfan-related conditions has shifted our current understanding to a pathogenic model that involves dysregulation of the cytokine-transforming growth factor beta (TGF-β) signaling.
In this review, we focus on the impact of the revised MFS clinical diagnostic criteria. We discuss lessons that have been learned from molecular findings in relevant Marfan-related conditions, such as sporadic thoracic aortic aneurysm/dissection, stiff skin syndrome, acromelic dysplasias and Loeys-Dietz syndrome. We explore the latest insights into the role of the alternative TGF-β signaling pathways in MFS pathogenesis. Finally, we give an update on the current and future treatment strategies.
The recent insights into the pathogenesis of MFS and related disorders have offered a prime example of translational medicine with immediate bridge between molecular findings and therapeutic options.
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