Identification of FBN1 gene mutations in Ukrainian Marfan syndrome patients.

Marfan syndrome is an autosomal dominant connective tissue disorder, predominantly affecting the ocular, skeletal and cardiovascular systems. Here, we present the results of the first genetic testing in 40 Ukrainian Marfan (-like) patients and 10 relatives. We applied a targeted next generation sequencing panel comprising FBN1 and 13 thoracic aortic aneurysm genes. We identified 27 causal mutations in FBN1, obtaining a mutation yield of 67·5%. A significant difference in age at aortic surgery between mutation positive and negative patients was observed. Thus, we conclude that genetic testing is important to identify patients at higher risk for developing life-threatening cardiovascular complications.

Performant Mutation Identification Using Targeted Next-Generation Sequencing of 14 Thoracic Aortic Aneurysm Genes.

At least 14 causative genes have been identified for both syndromic and nonsyndromic forms of thoracic aortic aneurysm/dissection (TAA), an important cause of death in the industrialized world. Molecular confirmation of the diagnosis is increasingly important for gene-tailored patient management but consecutive, conventional molecular TAA gene screening is expensive and labor-intensive. To circumvent these problems, we developed a TAA gene panel for next-generation sequencing of 14 TAA genes. After validation, we applied the assay to 100 Marfan patients. We identified 90 FBN1 mutations, 44 of which were novel. In addition, Multiplex ligation-dependent probe amplification identified large deletions in six of the remaining samples, whereas false-negative results were excluded by Sanger sequencing of FBN1, TGFBR1, and TGFBR2 in the last four samples. Subsequently, we screened 55 syndromic and nonsyndromic TAA patients. We identified causal mutations in 15 patients (27%), one in each of the six following genes: ACTA2, COL3A1, TGFBR1, MYLK, SMAD3, SLC2A10 (homozygous), two in NOTCH1, and seven in FBN1. We conclude that our approach for TAA genetic testing overcomes the intrinsic hurdles of consecutive Sanger sequencing of all candidate genes and provides a powerful tool for the elaboration of clinical phenotypes assigned to different genes.

Educational paper. Connective tissue disorders with vascular involvement: from gene to therapy.

Heritable connective tissue diseases comprise a heterogeneous group of multisystemic disorders that are characterized by significant morbidity and mortality. These disorders do not merely result from defects in the amount or structure of one of the components of the extracellular matrix, as the extracellular matrix also serves other functions, including sequestration of cytokines, such as transforming growth factor beta (TGFß). Indeed, disturbed TGFß signaling was demonstrated in several heritable connective tissue diseases, including syndromic forms such as Marfan or Loeys-Dietz syndrome and non-syndromic presentations of thoracic aortic aneurysm/dissection. Because of these findings, new therapeutic targets have been unveiled, leading to the initiation of large clinical trials with angiotensin II type 1 receptor antagonists that also have an inhibiting effect on TGFß signaling. Here, we present an overview of the clinical characteristics, the molecular findings, and the therapeutic strategies for the currently known syndromic and non-syndromic forms of thoracic aortic aneurysm/dissection.

Targeted Next-Generation Sequencing of 51 Genes Involved in Primary Electrical Disease.

Primary electrical disease (PED) is characterized by cardiac arrhythmias, which can lead to sudden cardiac death in the absence of detectable structural heart disease. PED encompasses a diversity of inherited syndromes, predominantly Brugada syndrome, early repolarization syndrome, long QT syndrome, short QT syndrome, arrhythmogenic right ventricular cardiomyopathy, and catecholaminergic polymorphic ventricular tachycardia. To overcome the diagnostic challenges imposed by the clinical and genetic heterogeneity of PED, we developed a targeted gene panel for next-generation sequencing of 51 PED genes. The amplified samples were sequenced on MiSeq. To validate the panel, 20 Human Polymorphism Study Center samples and 19 positive control samples were used, with a total of 1479 variants. An analytical sensitivity and specificity of 100% and 99.9% were obtained. After validation, we applied the assay to 114 PED patients. We identified 107 variants in 36 different genes, 18 of which were classified as pathogenic or likely pathogenic, 54 variants were of unknown significance, and 35 were classified as likely benign. We can conclude that the PED Multiplex Amplification of Specific Targets for Resequencing Plus assay is a proficient and highly reliable test to routinely screen patients experiencing primary arrhythmias.

Intermittent Brugada syndrome in an anorexic adolescent girl.

We report an anorexic adolescent girl with an intermittent Brugada syndrome. A 14-year-old anorexic girl with a body mass index (BMI) of 13.15 kg/m2 was admitted in the acute state of the disease with an ST elevation in V1 and V2, suggestive of Brugada syndrome. After 1 month of re-feeding, a control electrograph (ECG) was normal, but after an 8-month follow-up control with a nearly normal BMI, the ECG was again suggestive of Brugada syndrome. A genetic analysis of the gene SNC5A established a genetic change (p Leu 1582 pro), which provides the final explanation for the Brugada syndrome. Every rhythm problem in the acute state or during the re-feeding procedure deserves a strict follow-up to distinguish iatrogenic from heritable rhythm problems. .