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Purpose: Heterozygous pathogenic/likely pathogenic (P/LP) variants in the ACTA2 gene confer a high risk for thoracic aortic aneurysms and aortic dissections. This retrospective multicenter study elucidates the clinical outcome of ACTA2-related vasculopathies. Methods: Index patients and relatives with a P/LP variant in ACTA2 were included. Data were collected through retrospective review of medical records using a standardized questionnaire. Results: A total of 49 individuals from 28 families participated in our study. In total, 20 different ACTA2 variants were detected. Aortic events occurred in 65% of the cases (78.6% index patients and 47.6% relatives). Male sex and hypertension emerged as significantly associated with aortic events. Of 20 individuals, 5 had an aortic diameter of

Contains fulltext : 291333.pdf (Publisher’s version ) (Open Access) To optimize care for children with Marfan syndrome (MFS) in the Netherlands, Dutch MFS growth charts were constructed. Additionally, we aimed to investigate the effect of FBN1 variant type (haploinsufficiency [HI]/dominant negative [DN]) on growth, and compare MFS-related height increase across populations. Height and weight data of individuals with MFS aged 0-21 years were retrospectively collected. Generalized Additive Models for Location, Scale and Shape (GAMLSS) was used for growth chart modeling. To investigate genotype-phenotype relationships, FBN1 variant type was included as an independent variable in height-for-age and BMI-for-age models. MFS-related height increase was compared with that of previous MFS growth studies from the United States, Korea, and France. Height and weight data of 389 individuals with MFS were included (210 males). Height-for-age, BMI-for-age, and weight-for-height charts reflected the tall and slender MFS habitus throughout childhood. Mean increase in height of individuals with MFS compared with the general Dutch population was significantly lower than in the other three MFS populations compared to their reference populations. FBN1-HI variants were associated with taller height in both sexes, and decreased BMI in females (p-values

Vascular Ehlers-Danlos syndrome (vEDS) is a rare genetic disorder clinically characterized by vascular, intestinal and uterine fragility and caused by heterozygous pathogenic variants in the COL3A1 gene. Management of patients with vEDS is difficult due to the unpredictability of the events and clear recommendations on the care of adults and children with vEDS are lacking. Therefore, we aimed to collect data on the current strategy of surveillance and monitoring of vEDS patients by expert centers in continental Europe and Great Britain, as a first step towards a consensus statement. A survey on the clinical management of vEDS was sent to all members of the Medium Sized Artery (MSA) Working Group of the European Reference Network for Rare Vascular Diseases (VASCERN) and other expert centers. All experts endorse the importance of monitoring patients with vEDS. Despite the absence of evidence based guidelines monitoring is considered in almost all countries, but screening intervals and modalities used for monitoring may differ among centers. There is a need for more prospective multicenter studies to define proper guidelines.

International audience; Disease-causing variants in TGFB3 cause an autosomal dominant connective tissue disorder which is hard to phenotypically delineate because of the small number of identified cases. The purpose of this retrospective cross-sectional multicentre study is to elucidate the genotype and phenotype in an international cohort of TGFB3 patients. Eleven (8 novel) TGFB3 disease-causing variants were identified in 32 patients (17 families). Aortic root dilatation and mitral valve disease represented the most common cardiovascular findings, reported in 29% and 32% of patients, respectively. Dissection involving distal aortic segments occurred in two patients at age 50 and 52 years. A high frequency of systemic features (65% high-arched palate, 63% arachnodactyly, 57% pectus deformity, 52% joint hypermobility) was observed. In familial cases, incomplete penetrance and variable clinical expressivity were noted. Our cohort included the first described homozygous patient, who presented with a more severe phenotype compared to her heterozygous relatives. In conclusion, TGFB3 variants were associated with a high percentage of systemic features and aortic disease (dilatation/dissection) in 35% of patients. No deaths occurred from cardiovascular events or pregnancy-related complications. Nevertheless, homozygosity may be driving a more severe phenotype.

Simultaneous analysis of multiple genes using next‐generation sequencing (NGS) technology has become widely available. Copy‐number variations (CNVs) in disease‐associated genes have emerged as a cause for several hereditary disorders. CNVs are, however, not routinely detected using NGS analysis. The aim of this study was to assess the diagnostic yield and the prevalence of CNVs using our panel of Hereditary Thoracic Aortic Disease (H‐TAD)‐associated genes. Eight hundred ten patients suspected of H‐TAD were analyzed by targeted NGS analysis of 21 H‐TAD associated genes. In addition, the eXome hidden Markov model (XHMM; an algorithm to identify CNVs in targeted NGS data) was used to detect CNVs in these genes. A pathogenic or likely pathogenic variant was found in 66 of 810 patients (8.1%). Of these 66 pathogenic or likely pathogenic variants, six (9.1%) were CNVs not detectable by routine NGS analysis. These CNVs were four intragenic (multi‐)exon deletions in MYLK, TGFB2, SMAD3, and PRKG1, respectively. In addition, a large duplication including NOTCH1 and a large deletion encompassing SCARF2 were detected. As confirmed by additional analyses, both CNVs indicated larger chromosomal abnormalities, which could explain the phenotype in both patients. Given the clinical relevance of the identification of a genetic cause, CNV analysis using a method such as XHMM should be incorporated into the clinical diagnostic care for H‐TAD patients.

Contains fulltext : 169802.pdf (Publisher’s version ) (Closed access) The tenascin-X (TNX) deficient type Ehlers-Danlos syndrome (EDS) is similar to the classical type of EDS. Because of the limited awareness among geneticists and the challenge of the molecular analysis of the TNXB gene, the TNX-deficient type EDS is probably to be under diagnosed. We therefore performed an observational, cross-sectional study. History and physical examination were performed. Results of serum TNX measurements were collected and mutation analysis was performed by a combination of next-generation sequencing (NGS), Sanger sequencing and multiplex ligation-dependent probe amplification (MLPA). Included were 17 patients of 11 families with autosomal recessive inheritance and childhood onset. All patients had hyperextensible skin without atrophic scarring. Hypermobility of the joints was observed in 16 of 17 patients. Deformities of the hands and feet were observed frequently. TNX serum level was tested and absent in 11 patients (seven families). Genetic testing was performed in all families+ADs- 12 different mutations were detected, most of which are suspected to lead to non-sense mRNA mediated decay. In short, patients with the TNX-deficient type EDS typically have generalized joint hypermobility, skin hyperextensibility and easy bruising. In contrast to the classical type, the inheritance pattern is autosomal recessive and atrophic scarring is absent. Molecular analysis of TNXB in a diagnostic setting is challenging.

The natriuretic peptide signaling pathway has been implicated in many cellular processes, including endochondral ossification and bone growth. More precisely, different mutations in the NPR-B receptor and the CNP ligand have been identified in individuals with either short or tall stature. In this study we show that the NPR-C receptor (encoded by NPR3) is also important for the regulation of linear bone growth. We report four individuals, originating from three different families, with a phenotype characterized by tall stature, long digits, and extra epiphyses in the hands and feet. In addition, aortic dilatation was observed in two of these families. In each affected individual, we identified a bi-allelic loss-of-function mutation in NPR3. The missense mutations (c.442T>C [p.Ser148Pro] and c.1088A>T [p.Asp363Val]) resulted in intracellular retention of the NPR-C receptor and absent localization on the plasma membrane, whereas the nonsense mutation (c.1524delC [p.Tyr508*]) resulted in nonsense-mediated mRNA decay. Biochemical analysis of plasma from two affected and unrelated individuals revealed a reduced NTproNP/NP ratio for all ligands and also high cGMP levels. These data strongly suggest a reduced clearance of natriuretic peptides by the defective NPR-C receptor and consequently increased activity of the NPR-A/B receptors. In conclusion, this study demonstrates that loss-of-function mutations in NPR3 result in increased NPR-A/B signaling activity and cause a phenotype marked by enhanced bone growth and cardiovascular abnormalities.

Background: Phelan-McDermid syndrome (PMS), or 22q13.3 deletion syndrome, is a neurodevelopmental disorder with an estimated prevalence of 1 in 10,000 to 20,000 newborns. It usually occurs de novo, but an unexpectedly high recurrence risk is observed in some families. Our aim is to provide an overview of the underlying causes of recurrence in families with PMS and to summarize the available detection methods used to assess increased recurrence risk. Methods: We report clinical and (cyto)genetic data for five families with a high recurrence risk for PMS and provide an overview of Dutch families and cases from literature. We also outline a comprehensive work-up of additional cytogenetic testing to follow initial diagnosis in a proband. Results: Using fluorescent in situ hybridization (FISH), we confirmed a paternal translocation in two and a maternal mosaicism in three of our reported families. Of 34 cytogenetically investigated Dutch families, 16 to 20% have a high recurrence risk based on a parental chromosomal rearrangement. We found 18 additional families in the literature. Conclusions: Parental translocations and mosaicisms are not rare events in families with PMS, making follow-up FISH testing necessary. However, existing methods may still miss low-grade parental mosaicisms, and prenatal testing should always be offered.

Contains fulltext : 87594.pdf (Publisher’s version ) (Closed access) 01 oktober 2010