Design and rationale of a prospective, collaborative meta-analysis of all randomized controlled trials of angiotensin receptor antagonists in Marfan syndrome, based on individual patient data: A report from the Marfan Treatment Trialists' Collaboration.

RATIONALE: A number of randomized trials are underway, which will address the effects of angiotensin receptor blockers (ARBs) on aortic root enlargement and a range of other end points in patients with Marfan syndrome. If individual participant data from these trials were to be combined, a meta-analysis of the resulting data, totaling approximately 2,300 patients, would allow estimation across a number of trials of the treatment effects both of ARB therapy and of ß-blockade. Such an analysis would also allow estimation of treatment effects in particular subgroups of patients on a range of end points of interest and would allow a more powerful estimate of the effects of these treatments on a composite end point of several clinical outcomes than would be available from any individual trial. DESIGN: A prospective, collaborative meta-analysis based on individual patient data from all randomized trials in Marfan syndrome of (i) ARBs versus placebo (or open-label control) and (ii) ARBs versus ß-blockers will be performed. A prospective study design, in which the principal hypotheses, trial eligibility criteria, analyses, and methods are specified in advance of the unblinding of the component trials, will help to limit bias owing to data-dependent emphasis on the results of particular trials. The use of individual patient data will allow for analysis of the effects of ARBs in particular patient subgroups and for time-to-event analysis for clinical outcomes. The meta-analysis protocol summarized in this report was written on behalf of the Marfan Treatment Trialists' Collaboration and finalized in late 2012, without foreknowledge of the results of any component trial, and will be made available online (http://www.ctsu.ox.ac.uk/research/meta-trials).

Twenty patients including 7 probands with autosomal dominant cutis laxa confirm clinical and molecular homogeneity.

BACKGROUND: Elastin gene mutations have been associated with a variety of phenotypes. Autosomal dominant cutis laxa (ADCL) is a rare disorder that presents with lax skin, typical facial characteristics, inguinal hernias, aortic root dilatation and pulmonary emphysema. In most patients, frameshift mutations are found in the 3' region of the elastin gene (exons 30-34) which result in a C-terminally extended protein, though exceptions have been reported. METHODS: We clinically and molecularly characterized the thus far largest cohort of ADCL patients, consisting of 19 patients from six families and one sporadic patient. RESULTS: Molecular analysis showed C-terminal frameshift mutations in exon 30, 32, and 34 of the elastin gene and identified a mutational hotspot in exon 32 (c.2262delA). This cohort confirms the previously reported clinical constellation of skin laxity (100%), inguinal hernias (51%), aortic root dilatation (55%) and emphysema (37%). CONCLUSION: ADCL is a clinically and molecularly homogeneous disorder, but intra- and interfamilial variability in the severity of organ involvement needs to be taken into account. Regular cardiovascular and pulmonary evaluations are imperative in the clinical follow-up of these patients.

Osteogenesis Imperfecta: the audiological phenotype lacks correlation with the genotype.

BACKGROUND: Osteogenesis Imperfecta (OI) is a heritable connective tissue disorder mainly caused by mutations in the genes COL1A1 and COL1A2 and is associated with hearing loss in approximately half of the cases. The hearing impairment usually starts between the second and fourth decade of life as a conductive hearing loss, frequently evolving to mixed hearing loss thereafter. A minority of patients develop pure sensorineural hearing loss. The interindividual variability in the audiological characteristics of the hearing loss is unexplained. METHODS: With the purpose of evaluating inter- and intrafamilial variability, hearing was thorougly examined in 184 OI patients (type I: 154; type III: 4; type IV: 26), aged 3-89 years, with a mutation in either COL1A1 or COL1A2 and originating from 89 different families. Due to the adult onset of hearing loss in OI, correlations between the presence and/or characteristics of the hearing loss and the underlying mutation were investigated in a subsample of 114 OI patients from 64 different families who were older than 40 years of age or had developed hearing loss before the age of 40. RESULTS: Hearing loss was diagnosed in 48.4% of the total sample of OI ears with increasing prevalence in the older age groups. The predominant type was a mixed hearing loss (27.5%). A minority presented a pure conductive (8.4%) or pure sensorineural (12.5%) loss. In the subsample of 114 OI subjects, no association was found between the nature of the mutation in COL1A1 or COL1A2 genes and the occurrence, type or severity of hearing loss. Relatives originating from the same family differed in audiological features, which may partially be attributed to their dissimilar age. CONCLUSIONS: Our study confirms that hearing loss in OI shows a strong intrafamilial variability. Additional modifications in other genes are assumed to be responsible for the expression of hearing loss in OI.

The revised Ghent nosology for the Marfan syndrome.

The diagnosis of Marfan syndrome (MFS) relies on defined clinical criteria (Ghent nosology), outlined by international expert opinion to facilitate accurate recognition of this genetic aneurysm syndrome and to improve patient management and counselling. These Ghent criteria, comprising a set of major and minor manifestations in different body systems, have proven to work well since with improving molecular techniques, confirmation of the diagnosis is possible in over 95% of patients. However, concerns with the current nosology are that some of the diagnostic criteria have not been sufficiently validated, are not applicable in children or necessitate expensive and specialised investigations. The recognition of variable clinical expression and the recently extended differential diagnosis further confound accurate diagnostic decision making. Moreover, the diagnosis of MFS--whether or not established correctly--can be stigmatising, hamper career aspirations, restrict life insurance opportunities, and cause psychosocial burden. An international expert panel has established a revised Ghent nosology, which puts more weight on the cardiovascular manifestations and in which aortic root aneurysm and ectopia lentis are the cardinal clinical features. In the absence of any family history, the presence of these two manifestations is sufficient for the unequivocal diagnosis of MFS. In absence of either of these two, the presence of a bonafide FBN1 mutation or a combination of systemic manifestations is required. For the latter a new scoring system has been designed. In this revised nosology, FBN1 testing, although not mandatory, has greater weight in the diagnostic assessment. Special considerations are given to the diagnosis of MFS in children and alternative diagnoses in adults. We anticipate that these new guidelines may delay a definitive diagnosis of MFS but will decrease the risk of premature or misdiagnosis and facilitate worldwide discussion of risk and follow-up/management guidelines.

Altered TGFbeta signaling and cardiovascular manifestations in patients with autosomal recessive cutis laxa type I caused by fibulin-4 deficiency.

Fibulin-4 is a member of the fibulin family, a group of extracellular matrix proteins prominently expressed in medial layers of large veins and arteries. Involvement of the FBLN4 gene in cardiovascular pathology was shown in a murine model and in three patients affected with cutis laxa in association with systemic involvement. To elucidate the contribution of FBLN4 in human disease, we investigated two cohorts of patients. Direct sequencing of 17 patients with cutis laxa revealed no FBLN4 mutations. In a second group of 22 patients presenting with arterial tortuosity, stenosis and aneurysms, FBLN4 mutations were identified in three patients, two homozygous missense mutations (p.Glu126Lys and p.Ala397Thr) and compound heterozygosity for missense mutation p.Glu126Val and frameshift mutation c.577delC. Immunoblotting analysis showed a decreased amount of fibulin-4 protein in the fibroblast culture media of two patients, a finding sustained by diminished fibulin-4 in the extracellular matrix of the aortic wall on immunohistochemistry. pSmad2 and CTGF immunostaining of aortic and lung tissue revealed an increase in transforming growth factor (TGF)beta signaling. This was confirmed by pSmad2 immunoblotting of fibroblast cultures. In conclusion, patients with recessive FBLN4 mutations are predominantly characterized by aortic aneurysms, arterial tortuosity and stenosis. This confirms the important role of fibulin-4 in vascular elastic fiber assembly. Furthermore, we provide the first evidence for the involvement of altered TGFbeta signaling in the pathogenesis of FBLN4 mutations in humans.

Comprehensive clinical and molecular assessment of 32 probands with congenital contractural arachnodactyly: report of 14 novel mutations and review of the literature.

Beals-Hecht syndrome or congenital contractural arachnodactyly (CCA) is a rare, autosomal dominant connective tissue disorder characterized by crumpled ears, arachnodactyly, contractures, and scoliosis. Recent reports also mention aortic root dilatation, a finding previously thought to differentiate the condition from Marfan syndrome (MFS). In many cases, the condition is caused by mutations in the fibrillin 2 gene (FBN2) with 26 mutations reported so far, all located in the middle region of the gene (exons 23-34). We directly sequenced the entire FBN2 gene in 32 probands clinically diagnosed with CCA. In 14 probands, we found 13 new and one previously described FBN2 mutation including a mutation in exon 17, expanding the region in which FBN2 mutations occur in CCA. Review of the literature showed that the phenotype of the FBN2 positive patients was comparable to all previously published FBN2-positive patients. In our FBN2-positive patients, cardiovascular involvement included mitral valve prolapse in two adult patients and aortic root enlargement in three patients. Whereas the dilatation regressed in one proband, it remained marked in a child proband (z-score: 4.09) and his father (z-score: 2.94), warranting echocardiographic follow-up. We confirm paradoxical patellar laxity and report keratoconus, shoulder muscle hypoplasia, and pyeloureteral junction stenosis as new features. In addition, we illustrate large intrafamilial variability. Finally, the FBN2-negative patients in this cohort were clinically indistinguishable from all published FBN2-positive patients harboring a FBN2 mutation, suggesting locus heterogeneity.

Aneurysm syndromes caused by mutations in the TGF-beta receptor.

BACKGROUND: The Loeys-Dietz syndrome is a recently described autosomal dominant aortic-aneurysm syndrome with widespread systemic involvement. The disease is characterized by the triad of arterial tortuosity and aneurysms, hypertelorism, and bifid uvula or cleft palate and is caused by heterozygous mutations in the genes encoding transforming growth factor beta receptors 1 and 2 (TGFBR1 and TGFBR2, respectively). METHODS: We undertook the clinical and molecular characterization of 52 affected families. Forty probands presented with typical manifestations of the Loeys-Dietz syndrome. In view of the phenotypic overlap between this syndrome and vascular Ehlers-Danlos syndrome, we screened an additional cohort of 40 patients who had vascular Ehlers-Danlos syndrome without the characteristic type III collagen abnormalities or the craniofacial features of the Loeys-Dietz syndrome. RESULTS: We found a mutation in TGFBR1 or TGFBR2 in all probands with typical Loeys-Dietz syndrome (type I) and in 12 probands presenting with vascular Ehlers-Danlos syndrome (Loeys-Dietz syndrome type II). The natural history of both types was characterized by aggressive arterial aneurysms (mean age at death, 26.0 years) and a high incidence of pregnancy-related complications (in 6 of 12 women). Patients with Loeys-Dietz syndrome type I, as compared with those with type II, underwent cardiovascular surgery earlier (mean age, 16.9 years vs. 26.9 years) and died earlier (22.6 years vs. 31.8 years). There were 59 vascular surgeries in the cohort, with one death during the procedure. This low rate of intraoperative mortality distinguishes the Loeys-Dietz syndrome from vascular Ehlers-Danlos syndrome. CONCLUSIONS: Mutations in either TGFBR1 or TGFBR2 predispose patients to aggressive and widespread vascular disease. The severity of the clinical presentation is predictive of the outcome. Genotyping of patients presenting with symptoms like those of vascular Ehlers-Danlos syndrome may be used to guide therapy, including the use and timing of prophylactic vascular surgery.

Primary impairment of left ventricular function in Marfan syndrome.

BACKGROUND: Cardiovascular involvement in Marfan syndrome is mainly characterized by progressive dilatation of the proximal aorta. Whether left ventricular dysfunction is present in these patients is not clear at present. OBJECTIVES: Assess left ventricular function in patients with Marfan syndrome, free of significant valvular heart disease, using a combination of MRI and Tissue Doppler imaging (TDI). METHODS AND RESULTS: A total of 26 Marfan patients (mean age=32.0+/-10.9, 12 men) without significant valvular heart disease, and 26 age- and sex-matched controls were studied. Left ventricular volumes and ejection fraction were measured with magnetic resonance imaging. Systolic and diastolic function parameters were assessed using conventional echocardiography and TDI. When compared to controls, Marfan patients showed impairment of left ventricular contractile function as expressed by a reduced ejection fraction (53.5+/-9.0% vs. 59.6+/-6.7%, p=0.009), an increased end-systolic volume (36.0+/-9.5 vs. 29.5+/-6.7 ml/m(2), p=0.007), and reduced peak systolic velocities at the basal septal and lateral myocardial wall (5.2+/-1.4 vs. 6.4+/-1.3 cm/s, p=0.003 and 6.0+/-2.2 vs. 7.5+/-2.3 cm/s, p=0.03, respectively). Diastolic function was impaired with an increased deceleration time of the E wave (171+/-41 ms vs. 141+/-36 ms, p=0.006). Peak early diastolic velocity at the mitral valve annulus was significantly lower (9.6+/-2.4 cm/s vs. 11.9+/-3.3 cm/s, p=0.006). CONCLUSION: These data provide evidence for mild, but significant impairment of left ventricular systolic and diastolic function in Marfan patients, not related to valvular heart disease.

A syndrome of altered cardiovascular, craniofacial, neurocognitive and skeletal development caused by mutations in TGFBR1 or TGFBR2.

We report heterozygous mutations in the genes encoding either type I or type II transforming growth factor beta receptor in ten families with a newly described human phenotype that includes widespread perturbations in cardiovascular, craniofacial, neurocognitive and skeletal development. Despite evidence that receptors derived from selected mutated alleles cannot support TGFbeta signal propagation, cells derived from individuals heterozygous with respect to these mutations did not show altered kinetics of the acute phase response to administered ligand. Furthermore, tissues derived from affected individuals showed increased expression of both collagen and connective tissue growth factor, as well as nuclear enrichment of phosphorylated Smad2, indicative of increased TGFbeta signaling. These data definitively implicate perturbation of TGFbeta signaling in many common human phenotypes, including craniosynostosis, cleft palate, arterial aneurysms, congenital heart disease and mental retardation, and suggest that comprehensive mechanistic insight will require consideration of both primary and compensatory events.