Electron microscopy in the diagnosis of Ehlers-Danlos syndromes: correlation with clinical and genetic investigations.

BACKGROUND: The Ehlers-Danlos syndromes (EDS) consist of 13 subtypes with overlapping features including joint hypermobility, skin and vascular fragility and generalized connective tissue friability. As DNA analysis has become the gold standard for investigation of EDS, transmission electron microscopy (TEM) in clinical practice is decreasing. However, owing to the use of next-generation sequencing, the frequency of variants of uncertain significance (VUS) identified using DNA analysis is increasing. We hypothesized that TEM can provide evidence for or against pathogenicity of VUS. OBJECTIVES: The aim of this study was to evaluate the role of TEM in the diagnosis of EDS subtypes. METHODS: Data were collected from patients who underwent a skin biopsy between October 2012 and March 2017 at the London EDS National Diagnostic Service. TEM biopsies were categorized as 'normal' or 'abnormal' according to the description and conclusion in the TEM reports. Definitive diagnoses were reached via a combination of clinical features, structural and functional studies and DNA investigations. RESULTS: The analysis included 177 patients, comprising 30 abnormal and 147 normal TEM reports. A definitive diagnosis of monogenic EDS subtypes was made in 24 patients. Overall, 17 of these 24 patients (71%) had an abnormal biopsy report and seven (29%) had a normal biopsy report. No TEM findings were specifically associated with any EDS subtype, although collagen flowers were present in most patients with a genetically confirmed diagnosis of classical EDS. CONCLUSIONS: TEM analysis of collagen structure may have the potential to provide evidence for or against the pathogenicity of a VUS, but more work is needed to establish a clear role for TEM in this process. What's already known about this topic? Collagen fibril abnormalities can be seen in several Ehlers-Danlos syndrome (EDS) subtypes. What does this study add? This study provides clinical data, transmission electron microscopy (TEM) data and molecular data of one of the largest groups of patients suspected to have a monogenetic EDS subtype. No TEM findings were specifically associated with an EDS subtype. There was a higher percentage (71%) of abnormal biopsy findings in patients with a definitive diagnosis of a monogenetic EDS subtype and where a class 4/5 genetic variant was present.

Osteogenesis imperfecta: clinical diagnosis, nomenclature and severity assessment.

Recently, the genetic heterogeneity in osteogenesis imperfecta (OI), proposed in 1979 by Sillence et al., has been confirmed with molecular genetic studies. At present, 17 genetic causes of OI and closely related disorders have been identified and it is expected that more will follow. Unlike most reviews that have been published in the last decade on the genetic causes and biochemical processes leading to OI, this review focuses on the clinical classification of OI and elaborates on the newly proposed OI classification from 2010, which returned to a descriptive and numerical grouping of five OI syndromic groups. The new OI nomenclature and the pre-and postnatal severity assessment introduced in this review, emphasize the importance of phenotyping in order to diagnose, classify, and assess severity of OI. This will provide patients and their families with insight into the probable course of the disorder and it will allow physicians to evaluate the effect of therapy. A careful clinical description in combination with knowledge of the specific molecular genetic cause is the starting point for development and assessment of therapy in patients with heritable disorders including OI. © 2014 The Authors. American Journal of Medical Genetics Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Non-oral manifestations in adults with a clinical and molecularly confirmed diagnosis of periodontal Ehlers-Danlos syndrome.

Introduction: Periodontal Ehlers-Danlos Syndrome (pEDS) is a rare autosomal dominant type of EDS characterised by severe early-onset periodontitis, lack of attached gingiva, pretibial plaques, joint hypermobility and skin hyperextensibility as per the 2017 International EDS Classification. In 2016, deleterious pathogenic heterozygous variants were identified in C1R and C1S, which encode components of the complement system. Materials and Methods: Individuals with a clinical suspicion of pEDS were clinically and molecularly assessed through the National EDS Service in London and Sheffield and in genetic services in Austria, Sweden and Australia. Transmission electron microscopy and fibroblast studies were performed in a small subset of patients. Results: A total of 21 adults from 12 families were clinically and molecularly diagnosed with pEDS, with C1R variants in all families. The age at molecular diagnosis ranged from 21-73 years (mean 45 years), male: female ratio 5:16. Features of easy bruising (90%), pretibial plaques (81%), skin fragility (71%), joint hypermobility (24%) and vocal changes (38%) were identified as well as leukodystrophy in 89% of those imaged. Discussion: This cohort highlights the clinical features of pEDS in adults and contributes several important additional clinical features as well as novel deleterious variants to current knowledge. Hypothetical pathogenic mechanisms which may help to progress understanding and management of pEDS are also discussed.

A de novo mutation in ZMYND11, a candidate gene for 10p15.3 deletion syndrome, is associated with syndromic intellectual disability.

We report a boy with severe syndromic intellectual disability who has a de novo mutation in the ZMYND11 gene. Arguments for pathogenicity of this mutation are found in cases from the literature, especially several with 10p15.3 deletions, harbouring ZMYND11. Additional reports of ZMYND11 mutations in cases with syndromic intellectual disability are needed before the ZMYND11 mutation identified in our case can be considered as definitely pathogenic.

A novel homozygous 5 bp deletion in FKBP10 causes clinically Bruck syndrome in an Indonesian patient.

We report an Indonesian patient with bone fragility and congenital joint contractures. The initial diagnosis was Osteogenesis Imperfecta type III (OI type III) based on clinical and radiological findings. Because of (i) absence of COL1A1/2 mutations, (ii) a consanguineous pedigree with a similarly affected sibling and (iii) the existence of congenital joint contractures with absence of recessive variants in PLOD2, mutation analysis was performed of the FKBP10 gene, recently associated with Bruck syndrome and/or recessive OI. A novel homozygous deletion in FKBP10 was discovered. Our report of the first Indonesian patient with clinically Bruck syndrome, confirms the role of causative recessive FKBP10 mutations in this syndrome.

Solitary median maxillary central incisor and congenital nasal pyriform aperture stenosis combined with asymmetric crying facies and postaxial lower limb reduction defects: a unique combination of features.

We report a boy with asymmetric crying facies and bilateral absence of the 5th ray of the feet. In addition, craniofacial computed tomography showed a solitary median maxillary central incisor in combination with a narrow apertura piriformis. To our knowledge this intriguing combination of congenital abnormalities has not been described before.

Osteogenesis Imperfecta: A Review with Clinical Examples.

Osteogenesis imperfecta (OI) is characterized by susceptibility to bone fractures, with a severity ranging from subtle increase in fracture frequency to prenatal fractures. The first scientific description of OI dates from 1788. Since then, important milestones in OI research and treatment have, among others, been the classification of OI into 4 types (the 'Sillence classification'), the discovery of defects in collagen type I biosynthesis as a cause of most cases of OI and the use of bisphosphonate therapy. Furthermore, in the past 5 years, it has become clear that OI comprises a group of heterogeneous disorders, with an estimated 90% of cases due to a causative variant in the COL1A1 or COL1A2 genes and with the remaining 10% due to causative recessive variants in the 8 genes known so far, or in other currently unknown genes. This review aims to highlight the current knowledge around the history, epidemiology, pathogenesis, clinical/radiological features, management, and future prospects of OI. The text will be illustrated with clinical descriptions, including radiographs and, where possible, photographs of patients with OI.

Classification of Osteogenesis Imperfecta revisited.

In 1979 Sillence proposed a classification of Osteogenesis Imperfecta (OI) in OI types I, II, III and IV. In 2004 and 2007 this classification was expanded with OI types V-VIII because of distinct clinical features and/or different causative gene mutations. We propose a revised classification of OI with exclusion of OI type VII and VIII since these types have been added because of genetic criteria (autosomal recessive inheritance) while the clinical and radiological features are indistinguishable from OI types II-IV. Instead, we propose continued use of the Sillence criteria I, II-A, II-B, II-C, III and IV for clinical and radiological classification of OI with additional mentioning of the causative mutated gene to this classification. OI type V and VI are still part of this revised classification, because of the distinguishing clinical/radiological and/or histological features observed in these types.

Compound-heterozygous Marfan syndrome.

We report two families in which the probands have compound-heterozygous Marfan syndrome (MFS). The proband of family 1 has the R2726W FBN1 mutation associated with isolated skeletal features on one allele and a pathogenic FBN1 mutation on the other allele. The phenotype of the compound-heterozygous probands appears to be more severe than that of their heterozygous family members which underlines the possibility that certain trans-located FBN1 mutations might act as modifiers of phenotype explaining some of the intrafamilial variability in Marfan syndrome.

Rendu-Osler-Weber disease: update of medical and dental considerations.

Rendu-Osler-Weber disease, also known as hereditary hemorrhagic telangiectasia (HHT), is an autosomal dominant inherited disorder characterized by an aberrant vascular development. The reported prevalence is approximately 1 per 5,000-10,000. The clinical manifestations consist of recurrent spontaneous nosebleeds, telangiectasias characteristically at the lips, oral cavity, fingers, and nose, and visceral arteriovenous malformations. Timely recognition of this syndrome makes screening for complications, preventive measurements, and genetic counselling possible. The important role of the dental profession in the recognition of this genetic disease is emphasized. In addition, a brief overview of the current literature is presented.