Temporomandibular disorders among Ehlers-Danlos syndromes: a narrative review

This narrative review aims to demonstrate and summarize the complex relationship between Ehlers-Danlos syndromes (EDS) and temporomandibular disorders (TMD) by reviewing the results of observational studies and case reports. EDS are a set of hereditary connective tissue disorders, where generalized joint hypermobility (GJH), especially in the hypermobile subtype (hEDS), is a key symptom. Mutations have been identified in genes that impact the production or assembly of collagen for all subtypes except hEDS. While the correlation between GJH and TMD has been analysed in various studies, fewer studies have examined TMD in patients with EDS, with most showing an increased prevalence of TMD. In case-control studies, an elevated prevalence of myalgia, arthralgia and disc-related disorders was found in individuals with EDS. Various therapeutic interventions have been reported within the literature in the form of case reports and observational studies, but there are no long-term clinical trials with results on the efficacy of different therapeutic approaches to date. This review demonstrates the high prevalence of different TMDs in different subtypes of EDS, but also shows that little is known about the success of treatment thus far. Further clinical research is necessary to provide adequate guidance on targeted treatment.

Extracellular matrix in skin diseases: The road to new therapies

BACKGROUND

The extracellular matrix (ECM) is a vital structure with a dynamic and complex organization that plays an essential role in tissue homeostasis. In the skin, the ECM is arranged into two types of compartments: interstitial dermal matrix and basement membrane (BM). All evidence in the literature supports the notion that direct dysregulation of the composition, abundance or structure of one of these types of ECM, or indirect modifications in proteins that interact with them is linked to a wide range of human skin pathologies, including hereditary, autoimmune, and neoplastic diseases. Even though the ECM's key role in these pathologies has been widely documented, its potential as a therapeutic target has been overlooked.

AIM OF REVIEW

This review discusses the molecular mechanisms involved in three groups of skin ECM-related diseases - genetic, autoimmune, and neoplastic - and the recent therapeutic progress and opportunities targeting ECM.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This article describes the implications of alterations in ECM components and in BM-associated molecules that are determinant for guaranteeing its function in different skin disorders. Also, ongoing clinical trials on ECM-targeted therapies are discussed together with future opportunities that may open new avenues for treating ECM-associated skin diseases.

Cutis Laxa and the Value of Rhytidectomy: 4 Patients and Years of Follow-Up

The modalities of the esthetic treatment of cutis laxa (CL) patients have rarely been discussed. Here, the authors present 4 CL rhytidectomy cases. The surgery method was designed based on the traditional full-incision face-lift technique combined with lamellar superficial musculoaponeurotic system flap elevation and plication. Temporal, buccal, mandibular, and cervical regions were targeted. The shortest follow-up was 30 months, and the longest was 72. The results were assessed by subjective satisfaction and third-party photo evaluation. The subjective satisfaction was graded into worse than preoperation, no improvement, slight improvement, moderate improvement, and obvious improvement. The satisfaction rate was the sum of moderate and obvious improvement. Eighteen uncorrelated professionals participated in the third-party photo evaluation, in which the preoperative and follow-up photos were presented, and frontal, temporal, mid-face (including jowl), and cervical (including mandibular line) regions were evaluated as improved or nonimproved. The outcome of the subjective satisfaction was graded as no improvement (2/12, 16.7%), slight improvement (3/12, 25%), moderate improvement (4/12, 33.3%), and obvious improvement (3/12, 25%). The satisfaction rate was 58.3%, most investigators denied the frontal and temporal region improvement, 60% observed mid-face improvement, and 80% noticed cervical improvement. Most patients and their parents had positive attitudes towards the treatment results; however, the full expectation was not achieved. The cervical region maintained the best improvement after our treatment and the mid-face ranked second. This surgery method conduces to the esthetic requirement of CL patients; however, skin laxity remains a challenge.

Oral Health-Related Quality of Life in Different Subtypes of Ehlers-Danlos Syndrome

This study assessed differences in the oral health-related quality of life (OHRQoL) between subtypes of Ehlers-Danlos syndrome (EDS). For statistical analysis, participants were divided according to their subtype: classical EDS (cEDS), hypermobile EDS (hEDS), and vascular EDS (vEDS). All other subtypes were descriptively analyzed. Free-text questions and the German short form of the Oral Health Impact Profile (OHIP-14) were used. Finally, 295 questionnaires were included, representing 10 different EDS subtypes. The mean OHIP score of all participants was 19.6 points (standard derivation (SD) ± 12.3). The most predominant subtypes showed similar reduced OHRQoL, with 18.0 (cEDS, ±12.9), 19.5 (hEDS, ±12.0), and 15.2 (vEDS, ±11.6) OHIP points. For all other subtypes, the OHIP values varied. Participants waited an average of 21.8 years (±12.8) for their diagnosis. However, within the predominant subtypes, vEDS patients waited a noticeably shorter period of 13.3 years (±13.0; p = 0.004) compared to participants with hEDS. Additionally, this study showed no difference in OHRQoL for the predominant subtypes regardless of whether a participant was a self-help group member (18.8, ±12.0) or not (19.4, ±12.1; p = 0.327).

Prrx1 marks stem cells for bone, white adipose tissue and dermis in adult mice

Specialized connective tissues, including bone and adipose tissues, control various physiological activities, including mineral and energy homeostasis. However, the identity of stem cells maintaining these tissues throughout adulthood remains elusive. By conducting genetic lineage tracing and cell depletion experiments in newly generated knock-in Cre/CreER^T2 lines, we show here that rare Prrx1-expressing cells act as stem cells for bone, white adipose tissue and dermis in adult mice, which are indispensable for the homeostasis and repair of these tissues. Single-cell profiling reveals the cycling and multipotent nature of Prrx1-expressing cells and the stemness of these cells is further validated by transplantation assays. Moreover, we identify the cell surface markers for Prrx1-expressing stem cells and show that the activities of these stem cells are regulated by Wnt signaling. These findings expand our knowledge of connective tissue homeostasis/regeneration and may help improve stem-cell-based therapies.

Genetic Disorders of the Extracellular Matrix: From Cell and Gene Therapy to Future Applications in Regenerative Medicine

Metazoans have evolved to produce various types of extracellular matrix (ECM) that provide structural support, cell adhesion, cell-cell communication, and regulated exposure to external cues. Epithelial cells produce and adhere to a specialized sheet-like ECM, the basement membrane, that is critical for cellular homeostasis and tissue integrity. Mesenchymal cells, such as chondrocytes in cartilaginous tissues and keratocytes in the corneal stroma, produce a pericellular matrix that presents optimal levels of growth factors, cytokines, chemokines, and nutrients to the cell and regulates mechanosensory signals through specific cytoskeletal and cell surface receptor interactions. Here, we discuss laminins, collagen types IV and VII, and perlecan, which are major components of these two types of ECM. We examine genetic defects in these components that cause basement membrane pathologies such as epidermolysis bullosa, Alport syndrome, rare pericellular matrix-related chondrodysplasias, and corneal keratoconus and discuss recent advances in cell and gene therapies being developed for some of these disorders. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Quantifying Cell-Derived Changes in Collagen Synthesis, Alignment, and Mechanics in a 3D Connective Tissue Model

Dysregulation of extracellular matrix (ECM) synthesis, organization, and mechanics are hallmark features of diseases like fibrosis and cancer. However, most in vitro models fail to recapitulate the three-dimensional (3D) multi-scale hierarchical architecture of collagen-rich tissues and as a result, are unable to mirror native or disease phenotypes. Herein, using primary human fibroblasts seeded into custom fabricated 3D non-adhesive agarose molds, a novel strategy is proposed to direct the morphogenesis of engineered 3D ring-shaped tissue constructs with tensile and histological properties that recapitulate key features of fibrous connective tissue. To characterize the shift from monodispersed cells to a highly-aligned, collagen-rich matrix, a multi-modal approach integrating histology, multiphoton second-harmonic generation, and electron microscopy is employed. Structural changes in collagen synthesis and alignment are then mapped to functional differences in tissue mechanics and total collagen content. Due to the absence of an exogenously added scaffolding material, this model enables the direct quantification of cell-derived changes in 3D matrix synthesis, alignment, and mechanics in response to the addition or removal of relevant biomolecular perturbations. To illustrate this, the effects of nutrient composition, fetal bovine serum, rho-kinase inhibitor, and pro- and anti-fibrotic compounds on ECM synthesis, 3D collagen architecture, and mechanophenotype are quantified.

Rare Genetic Disorders Affecting the Periodontal Supporting Tissues in Adolescence

In adolescents periodontal destruction may be the primary manifestation of an as yet unrecognized rare systemic disease, and it may be up to the periodontist to make the correct tentative diagnosis. Many genetic diseases that present with primary periodontal manifestations in adolescence affect immune function, sometimes with only mild or absent systemic features. They include periodontal Ehlers-Danlos syndrome (lack of attached gingiva, various connective tissue abnormalities), Papillon-Lefèvre syndrome (palmoplantar hyperkeratosis), and plasminogen deficiency (fibrin deposition within mucous membranes). Other immune disorders with severe periodontitis manifesting in adolescence are usually diagnosed in early childhood due to unmistakeable systemic features. They include Cohen syndrome (developmental disorder, truncal obesity, and microcephaly), Hermansky-Pudlak Syndrome (oculocutaneous albinism, bleeding diathesis, and other systemic manifestations), glycogen storage disease type 1b, and Chediak-Higashi syndrome (pyogenic infections, albinism, and neuropathy). The structural integrity of periodontal tissue is affected in genodermatoses such as Kindler syndrome, a type of epidermolysis bullosa. In primary hyperoxaluria, inflammatory periodontal destruction is associated with renal calculi. Breakdown of periodontal tissues independent of dental plaque biofilm-induced periodontitis is found in hypophosphatasia (highly variable skeletal hypomineralization) or isolated odontohypophosphatasia, hypophosphatemic rickets and primary hyperparathyroidism. Finally, alveolar osteolysis mimicking localized periodontitis may be due to neoplastic processes, e.g., in neurofibromatosis type 1 (typical skin features including café au lait macules and neurofibromas), Langerhans cell histiocytosis (locally destructive proliferation of bone marrow-derived immature myeloid dendritic cells), and Gorham-Stout disease (diffuse cystic angiomatosis of bone).

Arterial Tortuosity Syndrome: An Ascorbate Compartmentalization Disorder?

Significance: Cardiovascular disorders are the most important cause of morbidity and mortality in the Western world. Monogenic developmental disorders of the heart and vessels are highly valuable to study the physiological and pathological processes in cardiovascular system homeostasis. The arterial tortuosity syndrome (ATS) is a rare, autosomal recessive connective tissue disorder showing lengthening, tortuosity, and stenosis of the large arteries, with a propensity for aneurysm formation. In histopathology, it associates with fragmentation and disorganization of elastic fibers in several tissues, including the arterial wall. ATS is caused by pathogenic variants in SLC2A10 encoding the facilitative glucose transporter (GLUT)10. Critical Issues: Although several hypotheses have been forwarded, the molecular mechanisms linking disrupted GLUT10 activity with arterial malformations are largely unknown. Recent Advances: The vascular and systemic manifestations and natural history of ATS patients have been largely delineated. GLUT10 was identified as an intracellular transporter of dehydroascorbic acid, which contributes to collagen and elastin cross-linking in the endoplasmic reticulum, redox homeostasis in the mitochondria, and global and gene-specific methylation/hydroxymethylation affecting epigenetic regulation in the nucleus. We revise here the current knowledge on ATS and the role of GLUT10 within the compartmentalization of ascorbate in physiological and diseased states. Future Directions: Centralization of clinical, treatment, and outcome data will enable better management for ATS patients. Establishment of representative animal disease models could facilitate the study of pathomechanisms underlying ATS. This might be relevant for other forms of vascular dysplasia, such as isolated aneurysm formation, hypertensive vasculopathy, and neovascularization. Antioxid. Redox Signal. 34, 875-889.

Correlation between Oral Health-Related Quality of Life and Objectively Measured Oral Health in People with Ehlers-Danlos Syndromes

It is a well-known fact that people with Ehlers–Danlos syndromes (EDS) report a worse oral health-related quality of life (OHRQoL) than the general population. The aim of this study was to examine whether there is a correlation between the subjective OHRQoL and the objectively measured oral health in people with EDS. To determine the subjective OHRQoL, the German version of the 14-item Oral Health Impact Profile (OHIP-14) questionnaire was used. Furthermore, all participants in the study were clinically examined, and the measured parameters were recorded using the Physical Oral Health Index (PhOX). Altogether, records of 46 participants were collected. The median (interquartile range (IQR)) of the OHIP-14 was 17 (23) points and the median of the PhOX was 73 (16) points. However, a statistically significant correlation could not be demonstrated (r = −0.240, p = 0.108). In the observed cohort, for participants who reported having pain often or very often, the OHIP score (median = 24, IQR = 18, p < 0.01) was higher than the score of the group given by participants who never or intermittently experienced pain (median = 8, IQR = 18). In conclusion, patients with EDS showed a reduced OHRQoL, although it was not possible to observe an association between the subjective OHRQoL and the objective oral health. However, participants who often or very often suffer from pain in their tooth, mouth, and jaw areas showed a reduced OHRQoL.

Cutis laxa: A comprehensive overview of clinical characteristics and pathophysiology

Cutis laxa (CL) syndromes comprise a rare group of multisystem disorders that share loose redundant skin folds as hallmark clinical feature. CL results from impaired elastic fiber assembly and homeostasis, and the known underlying gene defects affect different extracellular matrix proteins, intracellular trafficking, or cellular metabolism. Due to the underlying clinical and molecular heterogeneity, the diagnostic work-up of CL patients is often challenging. In this review, we provide a practical approach to the broad differential diagnosis of CL syndromes, provide an overview of the molecular pathogenesis of the different subtypes, and suggest general management guidelines.

Acromelic dysplasias: how rare musculoskeletal disorders reveal biological functions of extracellular matrix proteins

Acromelic dysplasias are a group of rare musculoskeletal disorders that collectively present with short stature, pseudomuscular build, stiff joints, and tight skin. Acromelic dysplasias are caused by mutations in genes (FBN1, ADAMTSL2, ADAMTS10, ADAMTS17, LTBP2, and LTBP3) that encode secreted extracellular matrix proteins, and in SMAD4, an intracellular coregulator of transforming growth factor-β (TGF-β) signaling. The shared musculoskeletal presentations in acromelic dysplasias suggest that these proteins cooperate in a biological pathway, but also fulfill distinct roles in specific tissues that are affected in individual disorders of the acromelic dysplasia group. In addition, most of the affected proteins directly interact with fibrillin microfibrils in the extracellular matrix and have been linked to the regulation of TGF-β signaling. Together with recently developed knockout mouse models targeting the affected genes, novel insights into molecular mechanisms of how these proteins regulate musculoskeletal development and homeostasis have emerged. Here, we summarize the current knowledge highlighting pathogenic mechanisms of the different disorders that compose acromelic dysplasias and provide an overview of the emerging biological roles of the individual proteins that are compromised. Finally, we develop a conceptual model of how these proteins may interact and form an "acromelic dysplasia complex" on fibrillin microfibrils in connective tissues of the musculoskeletal system.

Pyrroline-5-carboxylate synthase senses cellular stress and modulates metabolism by regulating mitochondrial respiration

Pyrroline-5-carboxylate synthase (P5CS) catalyzes the synthesis of pyrroline-5-carboxylate (P5C), a key precursor for the synthesis of proline and ornithine. P5CS malfunction leads to multiple human diseases; however, the molecular mechanism underlying these diseases is unknown. We found that P5CS localizes in mitochondria in rod- and ring-like patterns but diffuses inside the mitochondria upon cellular starvation or exposure to oxidizing agents. Some of the human disease-related mutant forms of P5CS also exhibit diffused distribution. Multimerization (but not the catalytic activity) of P5CS regulates its localization. P5CS mutant cells have a reduced proliferation rate and are sensitive to cellular stresses. Flies lacking P5CS have reduced eclosion rates. Lipid droplets accumulate in the eyes of the newly eclosed P5CS mutant flies, which degenerate with aging. The loss of P5CS in cells leads to abnormal purine metabolism and lipid-droplet accumulation. The reduced lipid-droplet consumption is likely due to decreased expression of the fatty acid transporter, CPT1, and few β-oxidation-related genes following P5CS knockdown. Surprisingly, we found that P5CS is required for mitochondrial respiratory complex organization and that the respiration defects in P5CS knockout cells likely contribute to the metabolic defects in purine synthesis and lipid consumption. This study links amino acid synthesis with mitochondrial respiration and other key metabolic processes, whose imbalance might contribute to P5CS-related disease conditions.

Recognizing genetic disease: A key aspect of pediatric pulmonary care

Advancement in technology has improved recognition of genetic etiologies of disease, which has impacted diagnosis and management of rare disease patients in the pediatric pulmonary clinic. This review provides an overview of genetic conditions that are likely to present with pulmonary features and require extensive care by the pediatric pulmonologist. Increased familiarity with these conditions allows for improved care of these patients by reducing time to diagnosis, tailoring management, and prompting further investigation into these disorders.

Mechanisms of aortic carboxypeptidase-like protein secretion and identification of an intracellularly retained variant associated with Ehlers-Danlos syndrome

Aortic carboxypeptidase-like protein (ACLP) is a collagen-binding extracellular matrix protein that has important roles in wound healing and fibrosis. ACLP contains thrombospondin repeats, a collagen-binding discoidin domain, and a catalytically inactive metallocarboxypeptidase domain. Recently, mutations in the ACLP-encoding gene, AE-binding protein 1 (AEBP1), have been discovered, leading to the identification of a new variant of Ehlers-Danlos syndrome causing connective tissue disruptions in multiple organs. Currently, little is known about the mechanisms of ACLP secretion or the role of post-translational modifications in these processes. We show here that the secreted form of ACLP contains N-linked glycosylation and that inhibition of glycosylation results in its intracellular retention. Using site-directed mutagenesis, we determined that glycosylation of Asn-471 and Asn-1030 is necessary for ACLP secretion and identified a specific N-terminal proteolytic ACLP fragment. To determine the contribution of secreted ACLP to extracellular matrix mechanical properties, we generated and mechanically tested wet-spun collagen ACLP composite fibers, finding that ACLP enhances the modulus (or stiffness), toughness, and tensile strength of the fibers. Some AEBP1 mutations were null alleles, whereas others resulted in expressed proteins. We tested the hypothesis that a recently discovered 40-amino acid mutation and insertion in the ACLP discoidin domain regulates collagen binding and assembly. Interestingly, we found that this protein variant is retained intracellularly and induces endoplasmic reticulum stress identified with an XBP1-based endoplasmic reticulum stress reporter. Our findings highlight the importance of N-linked glycosylation of ACLP for its secretion and contribute to our understanding of ACLP-dependent disease pathologies.

κ-helix and the helical lock and key model: a pivotal way of looking at polyproline II

Motivation

Polyproline II (PPII) is a common conformation, comparable to α-helix and β-sheet. PPII, recently termed with a more generic name—κ-helix, adopts a left-handed structure with 3-fold rotational symmetry. Lately, a new type of binding mechanism—the helical lock and key model was introduced in SH3-domain complexes, where the interaction is characterized by a sliding helical pattern. However, whether this binding mechanism is unique only to SH3 domains is unreported.

Results

Here, we show that the helical binding pattern is a universal feature of the κ-helix conformation, present within all the major target families—SH3, WW, profilin, MHC-II, EVH1 and GYF domains. Based on a geometric analysis of 255 experimentally solved structures, we found that they are characterized by a distinctive rotational angle along the helical axis. Furthermore, we found that the range of helical pitch varies between different protein domains or peptide orientations and that the interaction is also represented by a rotational displacement mimicking helical motion. The discovery of rotational interactions as a mechanism, reveals a new dimension in the realm of protein–protein interactions, which introduces a new layer of information encoded by the helical conformation. Due to the extensive involvement of the conformation in functional interactions, we anticipate our model to expand the current molecular understanding of the relationship between protein structure and function.

Availability and implementation

We have implemented the proposed methods in an R package freely available at https://github.com/Grantlab/bio3d.

Supplementary information

Supplementary data are available at Bioinformatics online.

Urogenital and pelvic complications in the Ehlers-Danlos syndromes and associated hypermobility spectrum disorders: A scoping review

The Ehlers-Danlos syndromes (EDS) and associated hypermobility spectrum disorders (HSD) are a heterogenous group of connective tissue disorders associated with significant morbidity. The urogenital aspects of these disorders are understudied and there is little guidance on the prevalence, types, or outcomes of urogenital complications in EDS/HSD. Our objective was to perform a scoping review to characterize and synthesize the literature reporting urogenital and pelvic complications in EDS/HSD patients. We performed a systematic search of three databases (Medline, CINAHL, Embase) to January 2019. English language, full-text articles reporting on urogenital or pelvic complications in EDS/HSD were included. A total of 105 studies were included (62 case reports/series, 43 observational) involving patients with hypermobile (23%), vascular (20%), classical (12%) EDS, and HSD (24%). Some studies looked at multiple subtypes (11%) or did not report subtype (33%). Reported complications included urinary (41%), gynecological (36%), obstetrical (25%), renal (9%), and men's health problems (7%), with some studies reporting on multiple areas. Urinary and gynecological complications were most prevalent in patients with HSD, while a broad range of complications were reported in EDS. While further research is required, results suggest a higher index of suspicion for urogenital problems is probably warranted in this population.

A Chinese family with periodontal Ehlers-Danlos syndrome associated with missense mutation in the C1R gene

AIM

We report a rare case of the periodontal Ehlers-Danlos syndrome (pEDS) associated with severe periodontitis and tooth loss in a Chinese family.

MATERIAL AND METHODS

The proband complained of gingival bleeding and mobility, which were also reported in his mother, and maternal uncle and his maternal grandmother and great-grandfather in the past. All family members underwent oral, physical, dermatological, and genetic examinations.

RESULTS

Oral manifestation of family members affected with pEDS presented severe periodontitis with multiple or total tooth loss. The proband displayed unique clinical manifestations including a characteristic facial appearance and thin, translucent skin with easily visible venous patterns on feet. Whole-exome sequencing identified missense mutation c.265T>C in C1R in all affected family members tested and frameshift mutation c.1322delG in COL3A1 in the proband alone. None of the unaffected members showed any marked oral, physical, dermatological, or genetic findings.

CONCLUSION

We reported an extremely rare case of pEDS with a missense mutation in C1R in a Chinese family, with coexistence C1R and COL3A1 mutations in the proband who was suspected to suffer from vascular EDS as well. To our knowledge, this is the first case of coexistence of two forms of EDS in a single individual.

A case of Ehlers-Danlos syndrome presenting with widened atrophic scars of forehead, elbow, knee, and pretibial area: A case report

RATIONAL

Ehlers-Danlos syndrome (EDS) is a heritable connective tissue disorder. Currently, the genotype-phenotype correlations of classical EDS (cEDS) are still controversial. Hence, this study reported a case of cEDS with both clinical manifestations and COL5A2 gene mutation.

PATIENT CONCERNS

A 30-year-old female presented to the plastic-surgery clinic with widen atrophic scars on forehead, elbows, knees and pretibial area that had developed since childhood.

DIAGNOSIS

With the skin hyperextensibility, joint hypermobility, papyraceous scar revealed by physical examination, and the heterozygous pathogenic variant c1997G > A (p.P659P) in COL5A2 gene revealed by whole exome sequencing, the diagnosis of the classical Ehlers-Danlos syndrome was made.

INTERVENTIONS

The patient underwent facial scar resection and sutured in minimizing tension and perfect apposition to avoid the post-surgery scar formation.

OUTCOMES

Follow-up 6 months after surgery, the wound remained a fine line scar.

LESSONS

Our findings suggested that COL5A2 gene mutation (c1997G > A p.P659P) may be associated with cEDS but did not reveal other severe complications.

Biomaterials to Mimic and Heal Connective Tissues

Connective tissue is one of the four major types of animal tissue and plays essential roles throughout the human body. Genetic factors, aging, and trauma all contribute to connective tissue dysfunction and motivate the need for strategies to promote healing and regeneration. The goal here is to link a fundamental understanding of connective tissues and their multiscale properties to better inform the design and translation of novel biomaterials to promote their regeneration. Major clinical problems in adipose tissue, cartilage, dermis, and tendon are discussed that inspire the need to replace native connective tissue with biomaterials. Then, multiscale structure-function relationships in native soft connective tissues that may be used to guide material design are detailed. Several biomaterials strategies to improve healing of these tissues that incorporate biologics and are biologic-free are reviewed. Finally, important guidance documents and standards (ASTM, FDA, and EMA) that are important to consider for translating new biomaterials into clinical practice are highligted.

Accuracy of Clinical Diagnostic Criteria for Patients With Vascular Ehlers-Danlos Syndrome in a Tertiary Referral Centre

Background:

Vascular Ehlers-Danlos syndrome is a rare inherited connective tissue disease secondary to mutations within the COL3A1 gene. The diagnosis of vascular Ehlers-Danlos syndrome is challenging, and patient selection for genetic testing relies on diagnostic criteria, which have never been evaluated.

Methods:

All patients seen at a dedicated tertiary referral center for a suspicion of vascular Ehlers-Danlos syndrome between January 2001 and March 2016 were retrospectively included in a diagnostic accuracy study. Major and minor diagnostic criteria of the Villefranche classification were tested for sensitivity, specificity, positive and negative predictive values, according to results of genetic testing.

Results:

N=519 patients were eligible for analysis dividing into n=384 probands and n=135 relatives. A pathogenic COL3A1 variant was identified in n=165 (31.8%) patients. The Villefranche criteria were met for n=248 patients with a sensitivity of 79% (95% CI, 0.72–0.85) and a negative predictive value of 87% (95% CI, 0.83–0.91). Diagnostic accuracy was highest for symptomatic probands (sensitivity 92%; negative predictive value 95%) with limited specificity (60%). Probands ≤25 years had the worst diagnostic performance. The revised diagnostic Criteria (2017) were less accurate than the Villefranche classification (overall diagnostic odds-ratio, 4.17 versus 7.8; probands diagnostic odds-ratio, 4.04 versus 18.1; and probands ≤25 years diagnostic odds-ratio, 2.36 versus 5.1) mainly due to a lack of sensitivity.

Conclusions:

The Villefranche criteria provide accurate detection of symptomatic probands in specialized practice but have limited specificity. The revised diagnostic criteria for vascular Ehlers-Danlos syndrome have increased specificity, but its overall performance is poorer. The early clinical diagnosis of probands without family history is not addressed by both diagnostic classifications.

Next-generation sequencing of 32 genes associated with hereditary aortopathies and related disorders of connective tissue in a cohort of 199 patients

PURPOSE

Heritable factors play an important etiologic role in connective tissue disorders (CTD) with vascular involvement, and a genetic diagnosis is getting increasingly important for gene-tailored, personalized patient management.

METHODS

We analyzed 32 disease-associated genes by using targeted next-generation sequencing and exome sequencing in a clinically relevant cohort of 199 individuals. We classified and refined sequence variants according to their likelihood for pathogenicity.

RESULTS

We identified 1 pathogenic variant (PV; in FBN1 or SMAD3) in 15 patients (7.5%) and ≥1 likely pathogenic variant (LPV; in COL3A1, FBN1, FBN2, LOX, MYH11, SMAD3, TGFBR1, or TGFBR2) in 19 individuals (9.6%), together resulting in 17.1% diagnostic yield. Thirteen PV/LPV were novel. Of PV/LPV-negative patients 47 (23.6%) showed ≥1 variant of uncertain significance (VUS). Twenty-five patients had concomitant variants. In-depth evaluation of reported/calculated variant classes resulted in reclassification of 19.8% of variants.

CONCLUSION

Variant classification and refinement are essential for shaping mutational spectra of disease genes, thereby improving clinical sensitivity. Obligate stringent multigene analysis is a powerful tool for identifying genetic causes of clinically related CTDs. Nonetheless, the relatively high rate of PV/LPV/VUS-negative patients underscores the existence of yet unknown disease loci and/or oligogenic/polygenic inheritance.

Bi-allelic Alterations in AEBP1 Lead to Defective Collagen Assembly and Connective Tissue Structure Resulting in a Variant of Ehlers-Danlos Syndrome

AEBP1 encodes the aortic carboxypeptidase-like protein (ACLP) that associates with collagens in the extracellular matrix (ECM) and has several roles in development, tissue repair, and fibrosis. ACLP is expressed in bone, the vasculature, and dermal tissues and is involved in fibroblast proliferation and mesenchymal stem cell differentiation into collagen-producing cells. Aebp1-/- mice have abnormal, delayed wound repair correlating with defects in fibroblast proliferation. In this study, we describe four individuals from three unrelated families that presented with a unique constellation of clinical findings including joint laxity, redundant and hyperextensible skin, poor wound healing with abnormal scarring, osteoporosis, and other features reminiscent of Ehlers-Danlos syndrome (EDS). Analysis of skin biopsies revealed decreased dermal collagen with abnormal collagen fibrils that were ragged in appearance. Exome sequencing revealed compound heterozygous variants in AEBP1 (c.1470delC [p.Asn490_Met495delins(40)] and c.1743C>A [p.Cys581∗]) in the first individual, a homozygous variant (c.1320_1326del [p.Arg440Serfs∗3]) in the second individual, and a homozygous splice site variant (c.1630+1G>A) in two siblings from the third family. We show that ACLP enhances collagen polymerization and binds to several fibrillar collagens via its discoidin domain. These studies support the conclusion that bi-allelic pathogenic variants in AEBP1 are the cause of this autosomal-recessive EDS subtype.

Multifaced Roles of the αvβ3 Integrin in Ehlers-Danlos and Arterial Tortuosity Syndromes' Dermal Fibroblasts

The αvβ3 integrin, an endothelial cells’ receptor-binding fibronectin (FN) in the extracellular matrix (ECM) of blood vessels, regulates ECM remodeling during migration, invasion, angiogenesis, wound healing and inflammation, and is also involved in the epithelial mesenchymal transition. In vitro-grown human control fibroblasts organize a fibrillar network of FN, which is preferentially bound on the entire cell surface to its canonical α5β1 integrin receptor, whereas the αvβ3 integrin is present only in rare patches in focal contacts. We report on the preferential recruitment of the αvβ3 integrin, due to the lack of FN–ECM and its canonical integrin receptor, in dermal fibroblasts from Ehlers–Danlos syndromes (EDS) and arterial tortuosity syndrome (ATS), which are rare multisystem connective tissue disorders. We review our previous findings that unraveled different biological mechanisms elicited by the αvβ3 integrin in fibroblasts derived from patients affected with classical (cEDS), vascular (vEDS), hypermobile EDS (hEDS), hypermobility spectrum disorders (HSD), and ATS. In cEDS and vEDS, respectively, due to defective type V and type III collagens, αvβ3 rescues patients’ fibroblasts from anoikis through a paxillin-p60Src-mediated cross-talk with the EGF receptor. In hEDS and HSD, without a defined molecular basis, the αvβ3 integrin transduces to the ILK-Snail1-axis inducing a fibroblast-to-myofibroblast-transition. In ATS cells, the deficiency of the dehydroascorbic acid transporter GLUT10 leads to redox imbalance, ECM disarray together with the activation of a non-canonical αvβ3 integrin-TGFBRII signaling, involving p125FAK/p60Src/p38MAPK. The characterization of these different biological functions triggered by αvβ3 provides insights into the multifaced nature of this integrin, at least in cultured dermal fibroblasts, offering future perspectives for research in this field.

Cutis laxa and excessive bone growth due to de novo mutations in PTDSS1

The cutis laxa syndromes are multisystem disorders that share loose redundant inelastic and wrinkled skin as a common hallmark clinical feature. The underlying molecular defects are heterogeneous and 13 different genes have been involved until now, all of them being implicated in elastic fiber assembly. We provide here molecular and clinical characterization of three unrelated patients with a very rare phenotype associating cutis laxa, facial dysmorphism, severe growth retardation, hyperostotic skeletal dysplasia, and intellectual disability. This disorder called Lenz–Majewski syndrome (LMS) is associated with gain of function mutations in PTDSS1, encoding an enzyme involved in phospholipid biosynthesis. This report illustrates that LMS is an unequivocal cutis laxa syndrome and expands the clinical and molecular spectrum of this group of disorders. In the neonatal period, brachydactyly and facial dysmorphism are two early distinctive signs, later followed by intellectual disability and hyperostotic skeletal dysplasia with severe dwarfism allowing differentiation of this condition from other cutis laxa phenotypes. Further studies are needed to understand the link between PTDSS1 and extra cellular matrix assembly.

Imaging in cutis laxa syndrome caused by a dominant negative ALDH18A1 mutation, with hypotheses for intracranial vascular tortuosity and wide perivascular spaces

The autosomal dominant progeroid form of cutis laxa is a recently identified multiple congenital anomaly disorder characterized by thin, wrinkled skin, a progeroid appearance, intra-uterine growth retardation, postnatal growth restriction, psychomotor developmental delay, microcephaly, cataract, hypotonia and contractures. De novo heterozygous mutations in ALDH18A1 have been described in this condition. We present neuroimaging abnormalities in three patients. One patient had intracranial arterial and venous tortuosity, widened ventricular and extra-axial cerebrospinal fluid (CSF) spaces, wide perivascular spaces and increased T2 signal intensity in the cerebral white matter over time. The second patient had vascular tortuosity. The third patient had prominent ventricular and extra-axial cerebrospinal fluid (CSF) spaces on CT. We propose an embryological mechanism for the development of intracranial vascular tortuosity and discuss the anatomical basis of wide perivascular spaces in relation to this syndrome. Although we do not know the clinical implications of these cerebral vascular anomalies, we suggest inclusion of neuroimaging in the baseline evaluation of these patients.

Periodontal manifestations of Ehlers-Danlos syndromes: A systematic review

AIM

Ehlers-Danlos syndromes (EDS) are a group of inherited connective tissue disorders, characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. Periodontal EDS (pEDS) is a specific EDS subtype caused by heterozygous mutations in complement 1 subunit genes C1R and C1S, with early severe periodontitis as predominant clinical feature. We aimed to systematically assess the spectrum of periodontal abnormalities in all EDS subtypes.

MATERIALS AND METHODS

An electronic and manual search was conducted in three databases (Medline, LIVIVO, CENTRAL). Publications of all study designs written in English/German without date restriction evaluating periodontal features in EDS were included.

RESULTS

Thirty articles on pEDS and thirteen articles on other EDS subtypes were analysed. In pEDS, early severe periodontitis (98.4%) and gingival recession (87.1%) are the predominant features. Reports on periodontal manifestations in other EDS subtypes are rare. Described were severe gingival enlargement in dermatosparaxis EDS, and localized periodontal breakdown related to teeth with shortened roots in classical EDS (n = 3, respectively).

CONCLUSION

Early severe periodontitis is the hallmark of pEDS; there is no evidence that it is part of the clinical phenotype of other EDS subtypes. Stringent analyses of periodontal manifestations in most EDS subtypes are missing. Prospero registration number CRD42017056889.

Mutations in ATP6V1E1 or ATP6V1A Cause Autosomal-Recessive Cutis Laxa

Defects of the V-type proton (H⁺) ATPase (V-ATPase) impair acidification and intracellular trafficking of membrane-enclosed compartments, including secretory granules, endosomes, and lysosomes. Whole-exome sequencing in five families affected by mild to severe cutis laxa, dysmorphic facial features, and cardiopulmonary involvement identified biallelic missense mutations in ATP6V1E1 and ATP6V1A, which encode the E1 and A subunits, respectively, of the V₁ domain of the heteromultimeric V-ATPase complex. Structural modeling indicated that all substitutions affect critical residues and inter- or intrasubunit interactions. Furthermore, complexome profiling, a method combining blue-native gel electrophoresis and liquid chromatography tandem mass spectrometry, showed that they disturb either the assembly or the stability of the V-ATPase complex. Protein glycosylation was variably affected. Abnormal vesicular trafficking was evidenced by delayed retrograde transport after brefeldin A treatment and abnormal swelling and fragmentation of the Golgi apparatus. In addition to showing reduced and fragmented elastic fibers, the histopathological hallmark of cutis laxa, transmission electron microscopy of the dermis also showed pronounced changes in the structure and organization of the collagen fibers. Our findings expand the clinical and molecular spectrum of metabolic cutis laxa syndromes and further link defective extracellular matrix assembly to faulty protein processing and cellular trafficking caused by genetic defects in the V-ATPase complex.

Periodontal Ehlers-Danlos Syndrome Is Caused by Mutations in C1R and C1S, which Encode Subcomponents C1r and C1s of Complement

Periodontal Ehlers-Danlos syndrome (pEDS) is an autosomal-dominant disorder characterized by early-onset periodontitis leading to premature loss of teeth, joint hypermobility, and mild skin findings. A locus was mapped to an approximately 5.8 Mb region at 12p13.1 but no candidate gene was identified. In an international consortium we recruited 19 independent families comprising 107 individuals with pEDS to identify the locus, characterize the clinical details in those with defined genetic causes, and try to understand the physiological basis of the condition. In 17 of these families, we identified heterozygous missense or in-frame insertion/deletion mutations in C1R (15 families) or C1S (2 families), contiguous genes in the mapped locus that encode subunits C1r and C1s of the first component of the classical complement pathway. These two proteins form a heterotetramer that then combines with six C1q subunits. Pathogenic variants involve the subunit interfaces or inter-domain hinges of C1r and C1s and are associated with intracellular retention and mild endoplasmic reticulum enlargement. Clinical features of affected individuals in these families include rapidly progressing periodontitis with onset in the teens or childhood, a previously unrecognized lack of attached gingiva, pretibial hyperpigmentation, skin and vascular fragility, easy bruising, and variable musculoskeletal symptoms. Our findings open a connection between the inflammatory classical complement pathway and connective tissue homeostasis.