WES/WGS Reporting of Mutations from Cardiovascular "Actionable" Genes in Clinical Practice: A Key Role for UMD Knowledgebases in the Era of Big Databases
International audience; High-throughput next-generation sequencing such as whole-exome and whole-genome sequencing are being rapidly integrated into clinical practice. The use of these techniques leads to the identification of secondary variants for which decisions about the reporting or not to the patient need to be made. The American College of Medical Genetics and Genomics recently published recommendations for the reporting of these variants in clinical practice for 56 "actionable" genes. Among these, seven are involved in Marfan Syndrome And Related Disorders (MSARD) resulting from mutations of the FBN1, TGFBR1 and 2, ACTA2, SMAD3, MYH11 and MYLK genes. Here, we show that mutations col…
Excess of de novo variants in genes involved in chromatin remodelling in patients with marfanoid habitus and intellectual disability.
PurposeMarfanoid habitus (MH) combined with intellectual disability (ID) (MHID) is a clinically and genetically heterogeneous presentation. The combination of array CGH and targeted sequencing of genes responsible for Marfan or Lujan–Fryns syndrome explain no more than 20% of subjects.MethodsTo further decipher the genetic basis of MHID, we performed exome sequencing on a combination of trio-based (33 subjects) or single probands (31 subjects), of which 61 were sporadic.ResultsWe identified eight genes with de novo variants (DNVs) in at least two unrelated individuals (ARID1B, ATP1A1, DLG4, EHMT1, NFIX, NSD1, NUP205 and ZEB2). Using simulation models, we showed that five genes (DLG4, NFIX, …
The revised ghent nosology; reclassifying isolated ectopia lentis
Inherited ectopia lentis (EL) is most commonly caused by Marfan syndrome (MFS), a multisystemic disorder caused by mutations in FBN1. Historically the diagnosis for patients with EL who have no systemic features of MFS is isolated EL (IEL). However, the Ghent nosology for MFS was updated in 2010 and made some important alterations. In particular, patients with EL and a FBN1 mutation are now categorically diagnosed with MFS, if their mutation has previously been described with aortic dilation/dissection. This carries significant systemic implications, as many patients previously diagnosed with IEL are now reclassified. We provide a review of all published cases of IEL caused by FBN1 mutation…
In-Frame Mutations in Exon 1 of SKI Cause Dominant Shprintzen-Goldberg Syndrome
International audience; Shprintzen-Goldberg syndrome (SGS) is characterized by severe marfanoid habitus, intellectual disability, camptodactyly, typical facial dysmorphism, and craniosynostosis. Using family-based exome sequencing, we identified a dominantly inherited heterozygous in-frame deletion in exon 1 of SKI. Direct sequencing of SKI further identified one overlapping heterozygous in-frame deletion and ten heterozygous missense mutations affecting recurrent residues in 18 of the 19 individuals screened for SGS; these individuals included one family affected by somatic mosaicism. All mutations were located in a restricted area of exon 1, within the R-SMAD binding domain of SKI. No mut…
Contribution of molecular analyses in diagnosing Marfan syndrome and type I fibrillinopathies: an international study of 1009 probands.
International audience; BACKGROUND: The diagnosis of Marfan syndrome (MFS) is usually initially based on clinical criteria according to the number of major and minor systems affected following international nosology. The number of FBN1 mutation carriers, at risk of aortic complications who would not be properly diagnosed based only on clinical grounds, is of growing importance owing to the increased availability of molecular screening. The aim of the study was to identify patients who should be considered for FBN1 mutation screening. METHODS: Our international series included 1009 probands with a known FBN1 mutation. Patients were classified as either fulfilling or not fulfilling "clinical"…
Familial hypercholesterolaemia is underdiagnosed and undertreated in the general population: guidance for clinicians to prevent coronary heart disease: Consensus Statement of the European Atherosclerosis Society
AIMS: The first aim was to critically evaluate the extent to which familial hypercholesterolaemia (FH) is underdiagnosed and undertreated. The second aim was to provide guidance for screening and treatment of FH, in order to prevent coronary heart disease (CHD).METHODS AND RESULTS: Of the theoretical estimated prevalence of 1/500 for heterozygous FH, <1% are diagnosed in most countries. Recently, direct screening in a Northern European general population diagnosed approximately 1/200 with heterozygous FH. All reported studies document failure to achieve recommended LDL cholesterol targets in a large proportion of individuals with FH, and up to 13-fold increased risk of CHD. Based on prev…
What do French patients and geneticists think about prenatal and preimplantation diagnoses in Marfan syndrome?
Objectives Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with manifestations mainly involving the skeletal, ocular, and cardiovascular systems. The phenotypic variability observed in MFS makes genetic counselling difficult. Prenatal diagnosis (PND) and preimplantation genetic diagnosis are technically feasible when a causal mutation is identified, but both raise many ethical questions in this condition. Little is known about opinions and practices in such reproductive issues in MFS. The goal of this study was to report on patients' points of view and geneticists' standard practices. Methods Two different questionnaires were produced. Results Fifty geneticists fil…
De novo 15q21.1q21.2 deletion identified through FBN1 MLPA and refined by 244K array-CGH in a female teenager with incomplete Marfan syndrome
International audience; Interstitial deletions involving the 15q21.1 band are very rare. Only 4 of these cases have been studied using molecular cytogenetic techniques in order to confirm the deletion of the whole FBN1 gene. The presence of clinical features of the Marfan syndrome (MFS) spectrum associated with mental retardation has been described in only 2/4 patients. Here we report on a 16-year-old female referred for suspicion of MFS (positive thumb and wrist sign, scoliosis, joint hyperlaxity, high-arched palate with dental crowding, dysmorphism, mitral insufficiency with dystrophic valve, striae). She had therefore 3 minor criteria according to the Ghent nosology. She also had speech …
MFAP5 Loss-of-Function Mutations Underscore the Involvement of Matrix Alteration in the Pathogenesis of Familial Thoracic Aortic Aneurysms and Dissections
Thoracic aortic aneurysm and dissection (TAAD) is an autosomal-dominant disorder with major life-threatening complications. The disease displays great genetic heterogeneity with some forms allelic to Marfan and Loeys-Dietz syndrome, and an important number of cases still remain unexplained at the molecular level. Through whole-exome sequencing of affected members in a large TAAD-affected family, we identified the c.472CT (p.Arg158(∗)) nonsense mutation in MFAP5 encoding the extracellular matrix component MAGP-2. This protein interacts with elastin fibers and the microfibrillar network. Mutation screening of 403 additional probands identified an additional missense mutation of MFAP5 (c.62GT …
The FBN2 gene: new mutations, locus-specific database (Universal Mutation Database FBN2), and genotype-phenotype correlations.
International audience; Congenital contractural arachnodactyly (CCA) is an extremely rare disease, due to mutations in the FBN2 gene encoding fibrillin-2. Another member of the fibrillin family, the FBN1 gene, is involved in a broad phenotypic continuum of connective-tissue disorders including Marfan syndrome. Identifying not only what is in common but also what differentiates these two proteins should enable us to better comprehend their respective functions and better understand the multitude of diseases in which these two genes are involved. In 1995 we created a locus-specific database (LSDB) for FBN1 mutations with the Universal Mutation Database (UMD) tool. To facilitate comparison of …
Homozygous familial hypercholesterolaemia: new insights and guidance for clinicians to improve detection and clinical management. A position paper from the Consensus Panel on Familial Hypercholesterolaemia of the European Atherosclerosis Society
Item does not contain fulltext AIMS: Homozygous familial hypercholesterolaemia (HoFH) is a rare life-threatening condition characterized by markedly elevated circulating levels of low-density lipoprotein cholesterol (LDL-C) and accelerated, premature atherosclerotic cardiovascular disease (ACVD). Given recent insights into the heterogeneity of genetic defects and clinical phenotype of HoFH, and the availability of new therapeutic options, this Consensus Panel on Familial Hypercholesterolaemia of the European Atherosclerosis Society (EAS) critically reviewed available data with the aim of providing clinical guidance for the recognition and management of HoFH. METHODS AND RESULTS: Early diagn…
Exome sequencing in suspected monogenic dyslipidemias.
Background— Exome sequencing is a promising tool for gene mapping in Mendelian disorders. We used this technique in an attempt to identify novel genes underlying monogenic dyslipidemias. Methods and Results— We performed exome sequencing on 213 selected family members from 41 kindreds with suspected Mendelian inheritance of extreme levels of low-density lipoprotein cholesterol (after candidate gene sequencing excluded known genetic causes for high low-density lipoprotein cholesterol families) or high-density lipoprotein cholesterol. We used standard analytic approaches to identify candidate variants and also assigned a polygenic score to each individual to account for their burden of commo…