Britta Keyser

Blood-based microRNA signatures differentiate various forms of cardiac hypertrophy

BACKGROUND Hypertrophic cardiomyopathy (HCM) is caused by mutations in different structural genes and induces pathological hypertrophy with sudden cardiac death as a possible consequence. HCM can be separated into hypertrophic non-obstructive and obstructive cardiomyopathy (HNCM/HOCM) with different clinical treatment approaches. We here distinguished between HNCM, HOCM, cardiac amyloidosis and aortic stenosis by using microRNA profiling and investigated potential interactions between circulating miRNA levels and the most common mutations in MYH7and MYBPC3 genes. METHODS Our study included 4 different groups: 23 patients with HNCM, 28 patients with HOCM, 47 patients with aortic stenosis and 22 healthy controls. Based on previous findings, 8 different cardiovascular known microRNAs (miR-1, miR-21, miR-29a, miR-29b, miR-29c, miR-133a, miR-155 and miR-499) were studied in serum of all patients and compared with clinically available patient data. RESULTS We found miR-29a levels to be increased in patients with HOCM and correlating markers of cardiac hypertrophy. This was not the case in HNCM patients. In contrast, we identified miR-29c to be upregulated in aortic stenosis but not the other patient groups. ROC curve analysis of miR-29a/c distinguished between HOCM patients and aortic stenosis patients. MiR-29a and miR-155 levels discriminated HNCM patients from patients with senile cardiac amyloidosis. MiR-29a increased mainly in HOCM patients with a mutation in MYH7, whereas miR-155 was decreased in hypertrophic cardiomyopathy patients with a mutation in MYBPC3. CONCLUSION We demonstrated that miR-29a and miR-29c show a specific signature to distinguish between aortic stenosis, hypertrophic non-obstructive and obstructive cardiomyopathies and thus could be developed into clinically useful biomarkers.

Analysis of phenotype and genotype information for the diagnosis of Marfan syndrome.

Sheikhzadeh S, Kade C, Keyser B, Stuhrmann M, Arslan‐Kirchner M, Rybczynski M, Bernhardt AM, Habermann CR, Hillebrand M, Mir T, Robinson PN, Berger J, Detter C, Blankenberg S, Schmidtke J, von Kodolitsch Y. Analysis of phenotype and genotype information for the diagnosis of Marfan syndrome.

Total serum transforming growth factor-β1 is elevated in the entire spectrum of genetic aortic syndromes.

Total serum transforming growth factor‐beta 1 (tsTGF‐β1) is increased in patients with Marfan syndrome (MFS), but it has not been assessed in thoracic aortic aneurysm and dissection (TAAD), Loeys‐Dietz syndrome (LDS), and bicuspid aortic valve disease (BAVD).

Observational Cohort Study of Ventricular Arrhythmia in Adults with Marfan Syndrome Caused by FBN1 Mutations

Background Marfan syndrome is associated with ventricular arrhythmia but risk factors including FBN1 mutation characteristics require elucidation. Methods and Results We performed an observational cohort study of 80 consecutive adults (30 men, 50 women aged 42±15 years) with Marfan syndrome caused by FBN1 mutations. We assessed ventricular arrhythmia on baseline ambulatory electrocardiography as >10 premature ventricular complexes per hour (>10 PVC/h), as ventricular couplets (Couplet), or as non-sustained ventricular tachycardia (nsVT), and during 31±18 months of follow-up as ventricular tachycardia (VT) events (VTE) such as sudden cardiac death (SCD), and sustained ventricular tachycardia (sVT). We identified >10 PVC/h in 28 (35%), Couplet/nsVT in 32 (40%), and VTE in 6 patients (8%), including 3 with SCD (4%). PVC>10/h, Couplet/nsVT, and VTE exhibited increased N-terminal pro–brain natriuretic peptide serum levels(P<.001). All arrhythmias related to increased NT-proBNP (P<.001), where PVC>10/h and Couplet/nsVT also related to increased indexed end-systolic LV diameters (P = .024 and P = .020), to moderate mitral valve regurgitation (P = .018 and P = .003), and to prolonged QTc intervals (P = .001 and P = .006), respectively. Moreover, VTE related to mutations in exons 24–32 (P = .021). Kaplan–Meier analysis corroborated an association of VTE with increased NT-proBNP (P<.001) and with mutations in exons 24–32 (P<.001). Conclusions Marfan syndrome with causative FBN1 mutations is associated with an increased risk for arrhythmia, and affected persons may require life-long monitoring. Ventricular arrhythmia on electrocardiography, signs of myocardial dysfunction and mutations in exons 24–32 may be risk factors of VTE.

Clinical utility gene card for: Hereditary thoracic aortic aneurysm and dissection including next-generation sequencing-based approaches

This CUGC intends to give guidance regarding molecular genetic testing in patients with thoracic aortic aneurysm and dissection (for definition see Loeys et al.1). It includes genes associated with nonsyndromic and syndromic conditions. In cases of a strong clinical suspicion for a particular syndrome, it recommends testing the respective associated genes first. In cases without such suspicion, it recommends either a stepwise approach by Sanger sequencing or, if available, NGS-based procedures according to the ESHG recommendations (Matthijs et al.2) based on ‘core genes’ and ‘additional genes’. The recommendations suggest that core gene lists are to be established by consensus among experts in the field. The ‘list must result in a ‘substantial contribution’ to the quality of life of a patient, and hence the genes must be chosen with care; a two tier system would be acceptable, whereby some genes are scrutinized more in detail (in other words: with a more complete coverage) than others; the list must not inflict with the efficiency of a service, that is, overzealous testing is not helpful; the use of core gene panels must lead to better diagnosis of the group of disorders, if not it lacks clinical utility.’2 Additional genes (those with a lower disease contribution) are optional components of the panel.

Dural ectasia in individuals with Marfan-like features but exclusion of mutations in the genes FBN1, TGFBR1 and TGFBR2

Sheikhzadeh S, Rybczynski M, Habermann CR, Bernhardt AMJ, Arslan‐Kirchner M, Keyser B, Kaemmerer H, Mir TS, Staebler A, Oezdal N, Robinson PN, Berger J, Meinertz T, von Kodolitsch Y. Dural ectasia in individuals with Marfan‐like features but exclusion of mutations in the genes FBN1, TGFBR1 and TGFBR2.

A simple clinical model to estimate the probability of Marfan syndrome

BACKGROUND Marfan syndrome is a heritable connective tissue disease. Definitive diagnosis is complex, and requires sequencing of a large gene, FBN1. AIM We aimed to develop a simple model to estimate the pre-test probability of Marfan syndrome. DESIGN Prospective cross-sectional study. METHODS We applied diagnostic standards for definitive diagnosis or exclusion of Marfan syndrome in 329 consecutive persons. In 208 persons with random assignment to our derivation group, we performed multivariate logistic regression to assess 14 clinical variables for inclusion in a prediction model with derivation of score points from the estimated coefficients. We created cut-offs to classify low, moderate and high probability of Marfan syndrome. For validation, we applied the model to the remaining 121 persons. RESULTS We identified seven variables for inclusion in the final model, where we assigned four score points to ectopia lentis, two points to a family history of Marfan syndrome, and one point to previous thoracic aortic surgery, to pectus excavatum, to a wrist and thumb sign, to previous pneumothorax, and to skin striae. In the derivation group 12, 42 and 92% of persons with low (≤1 point), moderate (>1-3.5 points) or high pre-test probability (>3.5 points) had Marfan syndrome, compared to 12, 57 and 91%, respectively, in the validation group. Positive likelihood ratios were 13.96 and 8.54 in the high probability group of the derivation and validation group, respectively. CONCLUSION A simple prediction model provides evidence for Marfan syndrome. This model can be used to identify patients who require definitive diagnostic work-up.

Comprehensive analysis of dural ectasia in 150 patients with a causative FBN1 mutation.

The purpose of this study was to perform a comprehensive study of dural ectasia (DE) related to FBN1 mutations. We performed a database analysis of two German metropolitan regions of 150 patients (68 men, 82 women; mean age 35 ± 16 years). All patients had a FBN1 mutation and underwent dural magnetic resonance imaging. Age was <16 years in 20, 16–25 in 27, 26–35 in 67, and >35 in 36 patients. Prevalence of dural ectasia was 89% with criteria of Oosterhof and Habermann, 83% with Fattori, 78% with Lundby, and 59% with Ahn. DE was less frequent in patients <16 years with Ahn and Fattori. DE related to skeletal manifestations with all criteria, to aortic Z‐scores and mitral valve prolapse with criteria of Habermann and Lundby, and to age with criteria of Fattori. The Fattori‐grade of DE increased with age, aortic Z‐scores, and skeletal score points. There was no consistent relationship of DE with any type of FBN1 mutation. DE is frequent in patients with FBN1 mutations irrespective of age and its severity increases during life. Criteria of Oosterhof and Habermann yielded most consistent diagnostic results. DE relates to skeletal involvement, aortic Z‐scores, and mitral valve prolapse.

FBN1 gene mutation characteristics and clinical features for the prediction of mitral valve disease progression

BACKGROUND Until today, FBN1 gene mutation characteristics were not compared with clinical features for the prediction of mitral valve disease progression. METHODS Therefore, we conducted a study of 116 patients (53 men, 63 women aged 33 ± 15 years) with a causative FBN1 gene mutation and ≤ moderate mitral valve regurgitation at baseline. RESULTS During 7.4 ± 6.8 years 30 patients developed progression of mitral valve regurgitation ≥ 1 grade (primary endpoint), and 26 patients required mitral valve surgery (secondary endpoint). Cox regression analysis identified an association of atrial fibrillation (hazard ratio (HR)=2.703; 95% confidence interval (CI) 1.013-7.211; P=.047), left ventricular ejection fraction (HR=.970; 95%CI .944-.997; P=.032), indexed end-diastolic left ventricular diameter (HR=15.165; 95%CI 4.498-51.128; P<.001), indexed left atrial diameter (HR=1.107; 95%CI 1.045-1.173; P=.001), tricuspid valve prolapse (HR=2.599; 95%CI 1.243-5.437; P=.011), posterior leaflet prolapse (HR=1.075; 95%CI 1.023-1.130; P=.009), and posterior leaflet thickening (HR=3.368; 95%CI 1.265-8.968; P=.015) with progression of mitral valve disease, whereas none of the FBN1 gene mutation characteristics were associated with progression of mitral valve disease. However, Cox regression analysis identified a marginal relationship of FBN1 gene mutations located both in a transforming-growth-factor beta-binding protein-like (TGFb-BP) domain (HR=3.453; 95%CI .982-12.143; P=.053), and in the calcium-binding epidermal growth factor-like (cbEGF) domain (HR=2.909; 95%CI .957-8.848; P=.060) with mitral valve surgery, a finding that was corroborated by Kaplan-Meier analysis (P=.014; and P=.041, respectively). CONCLUSION Clinical features were better predictors of mitral valve disease progression than FBN1 gene mutation characteristics.

Dural ectasia in Loeys-Dietz syndrome: comprehensive study of 30 patients with a TGFBR1 or TGFBR2 mutation

The purpose of this study was to assess the frequency, severity, and clinical associations of dural ectasia (DE) in Loeys–Dietz syndrome (LDS). Database analysis of three German metropolitan regions identified 30 patients with LDS and TGFBR1 mutation in 6 and a TGFBR2 mutation in 24 individuals (17 men; mean age: 31 ± 19 years), as well as 60 age and sex‐matched control patients with Marfan syndrome carrying a FBN1 mutation. DE was present in 22 patients with LDS (73%), and it related to skeletal score points (p = 0.008), non‐skeletal score points (p < 0.001), and to the presence of ≥7 systemic score points (p = 0.010). Similarly, the severity of DE was related to body height (p = 0.010) and non‐skeletal score points (p = 0.004). Frequency (p = 0.131) and severity of DE (p = 0.567) was similar in LDS and Marfan syndrome. DE is a manifestation of LDS that occurs with similar frequency and severity as in Marfan syndrome. Severity of DE may serve as a marker of the overall connective tissue disease severity. LDS may be considered in patients with DE.