Heritable Disorders Of Connective Tissue Research Articles

Expanding the phenotypic spectrum of Mendelian connective tissue disorders to include prominent kidney phenotypes.

Heritable connective tissue disorders are a group of diseases, each rare, characterized by various combinations of skin, joint, musculoskeletal, organ, and vascular involvement. Although kidney abnormalities have been reported in some connective tissue disorders, they are rarely a presenting feature. Here we present three patients with prominent kidney phenotypes who were found by whole exome sequencing to have variants in established connective tissue genes associated with Loeys-Dietz syndrome and congenital contractural arachnodactyly. These cases highlight the importance of considering connective tissue disease in children presenting with structural kidney disease and also serves to expand the phenotype of Loeys-Dietz syndrome and possibly congenital contractural arachnodactyly to include cystic kidney disease and cystic kidney dysplasia, respectively.

An Overview of Investigational and Experimental Drug Treatment Strategies for Marfan Syndrome.

Marfan syndrome (MFS) is a heritable connective tissue disorder caused by pathogenic variants in the gene coding for the extracellular matrix protein fibrillin-1. While the disease affects multiple organ systems, the most life-threatening manifestations are aortic aneurysms leading to dissection and rupture. Other cardiovascular complications, including mitral valve prolapse, primary cardiomyopathy, and arrhythmia, also occur more frequently in patients with MFS. The standard medical care relies on cardiovascular imaging at regular intervals, along with pharmacological treatment with β-adrenergic receptor blockers aimed at reducing the aortic growth rate. When aortic dilatation reaches a threshold associated with increased risk of dissection, prophylactic surgical aortic replacement is performed. Although current clinical management has significantly improved the life expectancy of patients with MFS, no cure is available and fatal complications still occur, underscoring the need for new treatment options. In recent years, preclinical studies have identified a number of potentially promising therapeutic targets. Nevertheless, the translation of these results into clinical practice has remained challenging. In this review, we present an overview of the currently available knowledge regarding the underlying pathophysiological processes associated with MFS cardiovascular pathology. We then summarize the treatment options that have been developed based on this knowledge and are currently in different stages of preclinical or clinical development, provide a critical review of the limitations of current studies and highlight potential opportunities for future research.

CRISPR/Cas9 in zebrafish: An attractive model for FBN1 genetic defects in humans.

BackgroundMutations in the fibrillin‐1 gene (FBN1) are associated with various heritable connective tissue disorders (HCTD). The most studied HCTD is Marfan syndrome. Ninety percent of Marfan syndrome is caused by mutations in the FBN1 gene. The zebrafish share high genetic similarity to humans, representing an ideal model for genetic research of human diseases. This study aimed to generate and characterize fbn1 +/− mutant zebrafish using the CRISPR/Cas9 gene‐editing technology.MethodsCRISPR/Cas9 was applied to generate an fbn1 frameshift mutation (fbn1 +/−) in zebrafish. F1 fbn1 +/− heterozygotes were crossed with transgenic fluorescent zebrafish to obtain F2 fbn1 +/− zebrafish. Morphological abnormalities were assessed in F2 fbn1 +/− zebrafish by comparing with the Tuebingen (TU) wild‐type controls at different development stages.ResultsWe successfully generated a transgenic line of fbn1 +/− zebrafish. Compared with TU wild‐type zebrafish, F2 fbn1 +/− zebrafish exhibited noticeably decreased pigmentation, increased lengths, slender body shape, and abnormal cardiac blood flow from atrium to ventricle.ConclusionWe generated the first fbn1 +/− zebrafish model using CRISPR/Cas9 gene‐editing approach to mimic FBN1 genetic defects in humans, providing an attractive model of Marfan syndrome and a method to determine the pathogenicity of gene mutation sites.

Clinical and molecular characteristics of 168 probands and 65 relatives with a clinical presentation of classical Ehlers-Danlos syndrome.

Classical Ehlers-Danlos syndrome (cEDS) is a heritable connective tissue disorder mainly caused by pathogenic variants in COL5A1 or COL5A2, encoding type V collagen. Its diagnosis, based on clinical criteria and molecular confirmation, can be challenging. We report the molecular and clinical characteristics of 168 probands (72 clinically evaluated at our center) and 65 relatives with a clinical presentation of cEDS. Type V collagen defects were found in 145 probands, 121 (83.5%) were located in COL5A1 and 24 (16.5%) in COL5A2. Although 85.6% of molecularly confirmed patients presented the two major clinical criteria (generalized joint hypermobility, hyperextensible skin with atrophic scarring), significant inter- and intrafamilial phenotypic variability was noted. COL5A2 variants often caused a more severe phenotype. Vascular complications were rare in individuals with type V collagen defects (1.4%). Among the 72 probands clinically evaluated in our center, the mutation detection rate was 82.0%. The majority (68.1%) harbored COL5A1/COL5A2 defects. Yet, 13.9% harbored a defect in another gene (COL1A1, PLOD1, TNXB, AEBP1) highlighting important clinical overlap and the need for molecular confirmation of the diagnosis as this has implications regarding follow-up and genetic counseling. Eighteen percent of the 72 probands remained molecularly unexplained and a COL5A1 variant of unknown significance was identified in 6.9%.

Loss of zebrafish atp6v1e1b, encoding a subunit of vacuolar ATPase, recapitulates human ARCL type 2C syndrome and identifies multiple pathobiological signatures.

The inability to maintain a strictly regulated endo(lyso)somal acidic pH through the proton-pumping action of the vacuolar-ATPases (v-ATPases) has been associated with various human diseases including heritable connective tissue disorders. Autosomal recessive (AR) cutis laxa (CL) type 2C syndrome is associated with genetic defects in the ATP6V1E1 gene and is characterized by skin wrinkles or loose redundant skin folds with pleiotropic systemic manifestations. The underlying pathological mechanisms leading to the clinical presentations remain largely unknown. Here, we show that loss of atp6v1e1b in zebrafish leads to early mortality, associated with craniofacial dysmorphisms, vascular anomalies, cardiac dysfunction, N-glycosylation defects, hypotonia, and epidermal structural defects. These features are reminiscent of the phenotypic manifestations in ARCL type 2C patients. Our data demonstrates that loss of atp6v1e1b alters endo(lyso)somal protein levels, and interferes with non-canonical v-ATPase pathways in vivo. In order to gain further insights into the processes affected by loss of atp6v1e1b, we performed an untargeted analysis of the transcriptome, metabolome, and lipidome in early atp6v1e1b-deficient larvae. We report multiple affected pathways including but not limited to oxidative phosphorylation, sphingolipid, fatty acid, and energy metabolism together with profound defects on mitochondrial respiration. Taken together, our results identify complex pathobiological effects due to loss of atp6v1e1b in vivo.

Developing a self-management intervention to manage hypermobility spectrum disorders (HSD) and hypermobile Ehlers-Danlos syndrome (hEDS): an analysis informed by behaviour change theory

Purpose Hypermobility Spectrum Disorders (HSD) and Hypermobile Ehlers-Danlos Syndrome (hEDS) are heritable connective tissue disorders associated with joint instability and pain, but with scant guidance for supporting patients. The aim was to determine recommendations for an HSD/hEDS self-management intervention. Materials and methods Barriers to self-management were mapped onto the Theoretical Domains Framework (TDF) and Capability, Opportunity, Motivation-Behaviour (COM-B) model in a behavioural analysis. A modified Nominal Group Technique was used to prioritise behaviour change technique (BCT) interventions (n = 9 women). Results Possible BCTs incorporated: Education Incorporating self-help strategies, education to improve their knowledge of HSD/hEDS, and how to judge information about HSD/hEDS. Training In activity pacing, assertiveness and communication skills, plus what to expect during pregnancy, when symptoms can worsen. Environmental restructuring and enablement Support from occupational therapists to maintain independence at work and home. Modelled behaviour That illustrates how other people with HSD/hEDS have coped with the psychosocial impact. Conclusions This study is the first to apply theoretically-informed approaches to the management of HSD/hEDS. Participants indicated poor access to psychological support, occupational therapy and a lack of knowledge about HSD/hEDS. Future research should evaluate which intervention options would be most acceptable and feasible. Implications for rehabilitation Patients with Hypermobility Spectrum Disorders or Hypermobile Ehlers-Danlos Syndrome can be active partners in the co-design of behaviour change interventions. Behaviour change interventions should target psychological support and patient education, particularly patient information. Additional behaviour change interventions included environmental restructuring and enablement; adaptations to participants’ environment with input from occupational therapy. Participants were keen to suggest opportunities for behavioural modelling; positive fist-person modelling narratives, written by those with HSD/hEDS, which addressed how they coped with the psychosocial impact of their condition.

Heritable Connective Tissue Disorders in Childhood: Increased Fatigue, Pain, Disability and Decreased General Health.

Heritable Connective Tissue Disorders (HCTD) show an overlap in the physical features that can evolve in childhood. It is unclear to what extent children with HCTD experience burden of disease. This study aims to quantify fatigue, pain, disability and general health with standardized validated questionnaires. Methods. This observational, multicenter study included 107 children, aged 4–18 years, with Marfan syndrome (MFS), 58%; Loeys-Dietz syndrome (LDS), 7%; Ehlers-Danlos syndromes (EDS), 8%; and hypermobile Ehlers-Danlos syndrome (hEDS), 27%. The assessments included PROMIS Fatigue Parent–Proxy and Pediatric self-report, pain and general health Visual-Analogue-Scales (VAS) and a Childhood Health Assessment Questionnaire (CHAQ). Results. Compared to normative data, the total HCTD-group showed significantly higher parent-rated fatigue T-scores (M = 53 (SD = 12), p = 0.004, d = 0.3), pain VAS scores (M = 2.8 (SD = 3.1), p < 0.001, d = 1.27), general health VAS scores (M = 2.5 (SD = 1.8), p < 0.001, d = 2.04) and CHAQ disability index scores (M = 0.9 (SD = 0.7), p < 0.001, d = 1.23). HCTD-subgroups showed similar results. The most adverse sequels were reported in children with hEDS, whereas the least were reported in those with MFS. Disability showed significant relationships with fatigue (p < 0.001, rs = 0.68), pain (p < 0.001, rs = 0.64) and general health (p < 0.001, rs = 0.59). Conclusions. Compared to normative data, children and adolescents with HCTD reported increased fatigue, pain, disability and decreased general health, with most differences translating into very large-sized effects. This new knowledge calls for systematic monitoring with standardized validated questionnaires, physical assessments and tailored interventions in clinical care.

Audiologic and Otologic Clinical Manifestations of Loeys-Dietz Syndrome: A Heritable Connective Tissue Disorder.

Loeys-Dietz syndrome (LDS) is a rare genetic connective tissue disorder resulting from TGF-ß signaling pathway defects and characterized by a wide spectrum of aortic aneurysm, arterial tortuosity, and various extravascular abnormalities. This study describes the audiologic, otologic, and craniofacial manifestations of LDS. Consecutive cross-sectional study. Tertiary medical research institute. Audiologic and clinical evaluations were conducted among 36 patients (mean ± SD age, 24 ± 17 years; 54% female) with genetically confirmed LDS. Cases were categorized into genetically based LDS types 1 to 4 (TGFBR1, TGFBR2, SMAD3, TGFB2, respectively). Audiometric characteristics included degree and type of hearing loss: subclinical, conductive, mixed, and sensorineural. LDS types 1 to 4 included 11, 13, 5, and 7 patients, respectively. In LDS-1, 27% had bilateral conductive hearing loss; 9%, unilateral mixed; and 36%, subclinical. In LDS-2, 38% had conductive hearing loss and 38% subclinical. In LDS-3 and LDS-4, 40% and 43% had bilateral sensorineural hearing loss, respectively. Degree of hearing loss ranged from mild to moderate. Bifid uvula was observed only in LDS-1 (55%) and LDS-2 (62%). Submucosal/hard cleft palates were primarily in LDS-1 and LDS-2. Posttympanostomy tympanic membrane perforations occurred in 45% (10/22 ears) of LDS-1 and LDS-2. There were 4 cases of cholesteatoma: 3 middle ear (LDS-1 and LDS-2) and 1 external ear canal (LDS-3). Conductive hearing loss, bifid uvula/cleft palate, and posttympanostomy tympanic membrane perforation are more common in LDS-1 and LDS-2 than LDS-3 and LDS-4, while sensorineural hearing loss was present only in LDS-3 and LDS-4. These LDS-associated key clinical presentations may facilitate an early diagnosis of LDS and thus prompt intervention to prevent related detrimental outcomes.

Impact of Intrinsic Muscle Weakness on Muscle-Bone Crosstalk in Osteogenesis Imperfecta.

Bone and muscle are highly synergistic tissues that communicate extensively via mechanotransduction and biochemical signaling. Osteogenesis imperfecta (OI) is a heritable connective tissue disorder of severe bone fragility and recently recognized skeletal muscle weakness. The presence of impaired bone and muscle in OI leads to a continuous cycle of altered muscle–bone crosstalk with weak muscles further compromising bone and vice versa. Currently, there is no cure for OI and understanding the pathogenesis of the skeletal muscle weakness in relation to the bone pathogenesis of OI in light of the critical role of muscle–bone crosstalk is essential to developing and identifying novel therapeutic targets and strategies for OI. This review will highlight how impaired skeletal muscle function contributes to the pathophysiology of OI and how this phenomenon further perpetuates bone fragility.

Muscle transcriptome in mouse models of osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a heritable connective tissue disorder that is most often caused by mutations in collagen type I encoding genes. Even though bone fragility is the most conspicuous finding in OI, the muscle system is also affected. In the present study we explored the muscle phenotype related to collagen type I mutations on the transcriptome level. RNA sequencing was performed in gastrocnemius muscles of homozygous oim mice and of heterozygous Jrt mice, two models of severe OI. We found that oim and Jrt mice shared 27 differentially expressed genes, of which 11 were concordantly upregulated and 15 concordantly downregulated. Gene Set Enrichment Analysis revealed that in both oim and Jrt mice, genes involved in 'metabolism of lipids' were significantly enriched among upregulated genes. In addition, several genes coding for extracellular matrix components were upregulated in both oim and Jrt mice. Among downregulated genes, genes involved in 'muscle contraction' were enriched in both OI mouse models. These 'muscle contraction' genes coded for slow-twitch type I muscle fiber components. Another shared downregulated gene was Mss51, a metabolic stress-inducible factor that is found in mitochondria. These data show that two mouse models of severe OI share abnormalities in the expression of genes that code for extracellular matrix proteins, lipid and energy metabolism and structural proteins of type I muscle fibers. The muscle disturbances resulting from the collagen type I mutations in these mouse models could be viewed as a mild form of muscle dystrophy.

Skeletal muscle specific mitochondrial dysfunction and altered energy metabolism in a murine model (oim/oim) of severe osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a heritable connective tissue disorder with patients exhibiting bone fragility and muscle weakness. The synergistic biochemical and biomechanical relationship between bone and muscle is a critical potential therapeutic target, such that muscle weakness should not be ignored. Previous studies demonstrated mitochondrial dysfunction in the skeletal muscle of oim/oim mice, which model a severe human type III OI. Here, we further characterize this mitochondrial dysfunction and evaluate several parameters of whole body and skeletal muscle metabolism. We demonstrate reduced mitochondrial respiration in female gastrocnemius muscle, but not in liver or heart mitochondria, suggesting that mitochondrial dysfunction is not global in the oim/oim mouse. Myosin heavy chain fiber type distributions were altered in the oim/oim soleus muscle with a decrease (−33 to 50%) in type I myofibers and an increase (+31%) in type IIa myofibers relative to their wildtype (WT) littermates. Additionally, altered body composition and increased energy expenditure were observed oim/oim mice relative to WT littermates. These results suggest that skeletal muscle mitochondrial dysfunction is linked to whole body metabolic alterations and to skeletal muscle weakness in the oim/oim mouse.

Adaptation of balance reactions following forward perturbations in people with joint hypermobility syndrome

BackgroundJoint Hypermobility Syndrome (JHS) is a Heritable Disorder of Connective tissue characterised by joint laxity and chronic widespread arthralgia. People with JHS exhibit a range of other symptoms including balance problems. To explore balance further, the objective of this study is to compare responses to forward perturbations between three groups; people who are hypermobile with (JHS) and without symptoms and people with normal flexibility.MethodsTwenty-one participants with JHS, 23 participants with Generalised Joint Hypermobility (GJH) and 22 participants who have normal flexibility (NF) stood on a platform that performed 6 sequential, sudden forward perturbations (the platform moved to the anterior to the participant). Electromyographic outcomes (EMG) and kinematics for the lower limbs were recorded using a Vicon motion capture system. Within and between group comparisons were made using Kruskal Wallis tests.ResultsThere were no significant differences between groups in muscle onset latency. At the 1st perturbation the group with JHS had significantly longer time-to-peak amplitude than the NF group in tibialis anterior, vastus medialis, rectus femoris, vastus lateralis, and than the GJH group in the gluteus medius. The JHS group showed significantly higher cumulative joint angle (CA) than the NF group in the hip and knee at the 1st and 2nd and 6th perturbation, and in the ankle at the 2nd perturbation. Participants with JHS had significantly higher CA than the GJH group at the in the hip and knee in the 1st and 2nd perturbation. There were no significant differences in TTR.ConclusionsThe JHS group were able to normalise the timing of their muscular response in relation to control groups. They were less able to normalise joint CA, which may be indicative of impaired balance control and strength, resulting in reduced stability.

Clinically relevant variants in a large cohort of Indian patients with Marfan syndrome and related disorders identified by next-generation sequencing

Marfan syndrome and related disorders are a group of heritable connective tissue disorders and share many clinical features that involve cardiovascular, skeletal, craniofacial, ocular, and cutaneous abnormalities. The majority of affected individuals have aortopathies associated with early mortality and morbidity. Implementation of targeted gene panel next-generation sequencing in these individuals is a powerful tool to obtain a genetic diagnosis. Here, we report on clinical and genetic spectrum of 53 families from India with a total of 83 patients who had a clinical diagnosis suggestive of Marfan syndrome or related disorders. We obtained a molecular diagnosis in 45/53 (85%) index patients, in which 36/53 (68%) had rare variants in FBN1 (Marfan syndrome; 63 patients in total), seven (13.3%) in TGFBR1/TGFBR2 (Loeys–Dietz syndrome; nine patients in total) and two patients (3.7%) in SKI (Shprintzen–Goldberg syndrome). 21 of 41 rare variants (51.2%) were novel. We did not detect a disease-associated variant in 8 (15%) index patients, and none of them met the Ghent Marfan diagnostic criteria. We found the homozygous FBN1 variant p.(Arg954His) in a boy with typical features of Marfan syndrome. Our study is the first reporting on the spectrum of variants in FBN1, TGFBR1, TGFBR2, and SKI in Indian individuals.

Parental mosaicism in Marfan and Ehlers\u2013Danlos syndromes and related disorders

Marfan syndrome (MFS) is a heritable connective tissue disorder (HCTD) caused by pathogenic variants in FBN1 that frequently occur de novo. Although individuals with somatogonadal mosaicisms have been reported with respect to MFS and other HCTD, the overall frequency of parental mosaicism in this pathology is unknown. In an attempt to estimate this frequency, we reviewed all the 333 patients with a disease-causing variant in FBN1. We then used direct sequencing, combined with High Resolution Melting Analysis, to detect mosaicism in their parents, complemented by NGS when a mosaicism was objectivized. We found that (1) the number of apparently de novo events is much higher than the classically admitted number (around 50% of patients and not 25% as expected for FBN1) and (2) around 5% of the FBN1 disease-causing variants were not actually de novo as anticipated, but inherited in a context of somatogonadal mosaicisms revealed in parents from three families. High Resolution Melting Analysis and NGS were more efficient at detecting and evaluating the level of mosaicism compared to direct Sanger sequencing. We also investigated individuals with a causal variant in another gene identified through our “aortic diseases genes” NGS panel and report, for the first time, on an individual with a somatogonadal mosaicism in COL5A1. Our study shows that parental mosaicism is not that rare in Marfan syndrome and should be investigated with appropriate methods given its implications in patient’s management.

Gastrointestinal medication burden among persons with the Ehlers-Danlos syndromes.

The Ehlers-Danlos syndromes (EDSs) are a group of heritable disorders of connective tissue associated with an increased prevalence of both structural and functional GI conditions. We used 10years (2005-2014) of administrative claims data comprised of 4294 people with clinician-diagnosed EDS, aged 5-62years, and compared their frequency of GI drug prescription claims to their age-, sex-, state of residence-, and earliest claim date-matched controls. We categorized the GI medications into the following groups: acid suppressants, anti-emetics, irritable bowel syndrome drugs, and visceral hypersensitivity (VHS) medications. Compared to controls, a significantly higher proportion of persons with EDS had prescription claims for at least one GI drug group, as well as for drugs in each of the four GI drug groups included in our study. By age-group, 25.7% children and 45.1% adults with EDS had prescription claims for at least one GI drug group compared with only 7.4% and 21.0% of controls, respectively (p<0.0001). By gender, 44.0% of women and 25.3% of men with EDS had prescription claims for at least one class of GI drugs compared with 19.2% and 9.6% of controls, respectively (p<0.0001). Predominant medication burden occurs among women with EDS, beginning peri-pubertally for anti-emetics and VHS drugs. High GI medication burden underscores previous evidence that GI dysmotility is common among persons with EDS.

Connective Tissue Disorders and Cardiovascular Complications: The Indomitable Role of Transforming Growth Factor-β Signaling.

Marfan Syndrome (MFS) and Loeys-Dietz Syndrome (LDS) represent heritable connective tissue disorders that segregate with a similar pattern of cardiovascular defects (thoracic aortic aneurysm, mitral valve prolapse/regurgitation, and aortic dilatation with regurgitation). This pattern of cardiovascular defects appears to be expressed along a spectrum of severity in many heritable connective tissue disorders and raises suspicion of a relationship between the normal development of connective tissues and the cardiovascular system. With overwhelming evidence of the involvement of aberrant Transforming Growth Factor-beta (TGF-β) signaling in MFS and LDS, this signaling pathway may represent the common link in the relationship between connective tissue disorders and their associated cardiovascular complications. To further explore this hypothetical link, this chapter will review the TGF-β signaling pathway, the heritable connective tissue syndromes related to aberrant TGF-β signaling, and will discuss the pathogenic contribution of TGF-β to these syndromes with a primary focus on the cardiovascular system.

A review of respiratory manifestations and their management in Ehlers-Danlos syndromes and hypermobility spectrum disorders.

Background:Ehlers-Danlos Syndromes (EDS) and Hypermobility Spectrum Disorders (HSD) are a heterogeneous group of heritable genetic connective tissue disorders with multiple characteristics including joint hypermobility, tissue fragility, and multiple organ dysfunction. Respiratory manifestations have been described in EDS patients, but have not been systematically characterized. A narrative review was undertaken to describe the respiratory presentations and management strategies of individuals with EDS and HSD.Methods:A broad literature search of Medline, Embase, Cochrane Database of Systematic Reviews, and Cochrane CENTRAL was undertaken from inception to November 2020 of all study types, evaluating EDS/ HSD and pulmonary conditions. This narrative review was limited to adult patients and publications in English.Results:Respiratory manifestations have generally been described in hypermobile EDS (hEDS), classical and vascular EDS subtypes. Depending on EDS subtype, they may include but are not limited to dyspnea, dysphonia, asthma, sleep apnea, and reduced respiratory muscle function, with hemothorax and pneumothorax often observed with vascular EDS. Respiratory manifestations in HSD have been less frequently characterized in the literature, but exertional dyspnea is the more common symptom described. Respiratory symptoms in EDS can have an adverse impact on quality of life. The respiratory management of EDS patients has followed standard approaches with thoracotomy tubes and pleurodesis for pleural manifestations, vocal cord strengthening exercises, continuous positive pressure support for sleep apnea, and exercise training. Reduced respiratory muscle function in hEDS patients responds to inspiratory muscle training.Conclusion:Respiratory symptoms and manifestations are described in EDS and HSD, and have generally been managed using conservative non-surgical strategies. Research into the prevalence, incidence and specific respiratory management strategies in EDS and HSD is needed to mitigate some of the associated morbidity.

Oral manifestations and rehabilitation of a patient with osteogenesis imperfecta

Introduction. Osteogenesis imperfecta is a rare heritable connective tissue disorder characterized by increased fragility of the bony tissue. The incidence of orofacial alterations associated with osteogenesis imperfecta is variable and includes dentinogenesis imperfecta, malocclusions, hypoplasia of the jaws, delayed dental development and structural abnormalities of the teeth. Case outline. A 22-year-old female was referred to the Clinic for Pediatric and Preventive Dentistry for dental treatment. Enlarged head, triangular-shaped face, mandibular prognathism with excessive maxillary hypoplasia, lowered vertical occlusal dimension were present features. The intraoral findings included dentinogenesis imperfecta with Kennedy?s class IV in the upper jaw and class II in the lower jaw. Panoramic radiograph revealed abnormalities in the crown and root shape, obliteration of the pulp chamber and severe deficiency of alveolar bone mass. Overall treatment involved five phases: I ? preventive and prophylactic treatment, II ? direct restauration of five teeth with glass ionomer cement, III ? extraction of severely damaged teeth, IV ? prosthodontic rehabilitation with removable partial dentures, V ? maintenance and follow-up phase. Conclusion. Low prevalence and wide variety of signs and symptoms make dental treatment of osteogenesis imperfecta overly complex and challenging. Nevertheless, it is essential to improve craniofacial and dental function along with facial aesthetic.

The Roles of Tenascins in Cardiovascular, Inflammatory, and Heritable Connective Tissue Diseases.

Tenascins are a family of multifunctional extracellular matrix (ECM) glycoproteins with time- and tissue specific expression patterns during development, tissue homeostasis, and diseases. There are four family members (tenascin-C, -R, -X, -W) in vertebrates. Among them, tenascin-X (TNX) and tenascin-C (TNC) play important roles in human pathologies. TNX is expressed widely in loose connective tissues. TNX contributes to the stability and maintenance of the collagen network, and its absence causes classical-like Ehlers-Danlos syndrome (clEDS), a heritable connective tissue disorder. In contrast, TNC is specifically and transiently expressed upon pathological conditions such as inflammation, fibrosis, and cancer. There is growing evidence that TNC is involved in inflammatory processes with proinflammatory or anti-inflammatory activity in a context-dependent manner. In this review, we summarize the roles of these two tenascins, TNX and TNC, in cardiovascular and inflammatory diseases and in clEDS, and we discuss the functional consequences of the expression of these tenascins for tissue homeostasis.

Bone Mass, Density, Geometry, and Stress-Strain Index in Adults With Osteogenesis Imperfecta Type I and Their Associations With Physical Activity and Muscle Function Parameters.

Osteogenesis imperfecta (OI) is a clinically and genetically heterogeneous heritable connective tissue disorder mainly characterized by bone fragility and increased fracture risk. This study investigated bone parameters in adults with OI type I and their relationship with physical activity and muscle function parameters in comparison with controls. A total of 27 (15 women, 12 men) adults with OI type I and 27 healthy age- and sex-matched controls, with mean age 45 years (range 18-72 years), were included. Peripheral quantitative computed tomography was performed at the lower leg and forearm to assess muscle density, muscle and fat cross-sectional area (CSA) (66% site), and trabecular (4% site) and cortical bone parameters (66% site) at radius and tibia. Physical activity (step count and moderate-to-vigorous physical activity [MVPA]) was assessed by accelerometry, muscle function parameters by Leonardo mechanography (single two-legged jump - peak power), and hand grip dynamometry (maximal hand grip strength). Overall, the OI type I group had significantly lower muscle CSA at the lower leg and forearm, lower trabecular and cortical bone mineral content, lower polar stress-strain index (SSIp), and smaller cortices but higher cortical bone mineral density and lower step count and MVPA in comparison with controls. Maximal hand grip strength was positively associated with SSIp at radius (p=0.012) in the control group but not in the OI type I group (p=0.338) (difference in associations: p=0.012). No other significantly different associations between bone and muscle function parameters or physical activity (step count or MVPA) were found in the OI type I versus control group. We conclude that adults with OI type I have smaller bones, lower trabecular bone mass, lower estimates of bone strength, and higher cortical density in comparison with controls and that there are some indications of a disturbed biomechanical muscle-bone relationship in adults with OI type I. © 2022 American Society for Bone and Mineral Research (ASBMR).