COL7A1 Mutations Research Articles

Abstract 15123: Adult Human Cardiomyocyte Mechanics in Osteogenesis Imperfecta

Introduction: Osteogenesis imperfecta (OI) is an extracellular matrix (ECM) disorder characterized by defects in collagen 1 transport or synthesis. While reduced collagen in OI hearts have been associated with reduced myocardial stiffness and left ventricular remodeling, its consequences on cardiomyocyte (CM) function have not been studied. Here we explore the tissue-level and CM-level properties of a heart from a deceased organ donor with OI Type I (heterozygous c.1821+1G>A mutation in COL1A1). Methods: The OI heart and non-failing (Control) hearts were obtained at the time of organ donation and arrested using ice-cold cardioplegia. Portions of the left ventricle were flash frozen or fixed for molecular assays. Trabeculae were dissected and passive mechanics assessed. The left anterior descending artery was cannulated and perfused with collagenase to isolate single CMs, which were then cultured on physiologic (10 kPa) or pathologic (50 kPa) stiffness substrates. CM contractility was assessed after 24 or 48 hours of culture. Results: Immunoblot and histology confirmed approximately 50% reduction of collagen 1 in OI vs. Control. Trabecular stretch demonstrated low stiffness at the tissue level. Isolated CMs from the OI heart were hypercontractile relative to non-failing controls after 24 hours of culture regardless of culture stiffness. In response to 48 hours of culture, OI CMs demonstrated an exaggerated stiffness-dependent reduction in contractility (sarcomere shortening on 50 kPa substrate- Controls: 0.10±0.01 μm vs. OI: 0.04±0.07 μm, p<0.01) suggesting that OI CMs may have an impaired stress response. Levels of detyrosinated tubulin, known to be responsive to ECM stiffness, were 30% reduced in OI. Conclusions: These data confirm CM level adaptations to reduced ECM stiffness that extend our understanding of OI in the heart and suggests that CMs adapted to a constitutively low stiffness environment may be less able to respond to increased external loads.

Case Report: A prenatal diagnosis of osteogenesis imperfecta in a patient with a novel pathogenic variant in COL1A2

Osteogenesis imperfecta is considered a rare genetic condition which is characterized by bone fragility. In 85% of cases, it is caused by mutations in COL1A1 and COL1A2 genes which are essential to produce type I collagen. We report the case of a female neonate delivered to a 27-year-old women at San Bartolomé Teaching Hospital with a family history of clavicle fracture. A prenatal control with ultrasound was performed to the mother at 29 weeks. A fetus with altered morphology and multiple fractures was found. Therefore, a prenatal diagnosis of osteogenesis imperfecta was performed. The neonate was born with a respiratory distress syndrome and an acyanotic congenital heart disease. Therefore, she remained in NICU until her death. We highlight the importance of prenatal diagnosis, genetic counseling and a multidisciplinary evaluation in this type of pathologies and report a new probably pathogenic variant in the COL1A2 gene detected by exomic sequencing in amniotic fluid.

Chronic Pediatric Retinal Detachment with Multiple Macrocysts.

To describe a case of chronic pediatric retinal detachment with multiple macrocysts, its surgical management, and a review of the literature. Case report with fundus photography and optical coherence tomography. We describe a case of an asymptomatic, 11-year-old male with a chronic rhegmatogenous retinal detachment with multiple peripheral macrocysts. The patient had count fingers visual acuity upon presentation. The detachment was successfully surgically repaired with scleral buckling, subretinal fluid drainage, cryotherapy, with a SF6 tamponade. At the 12-month follow-up, the retina remained attached with improvement of visual acuity to 20/100 with resolution of the cysts. Optical coherence tomography revealed loss of macular ellipsoid zone. Genetic testing revealed a heterozygous dominant COL11A1 mutation. To the authors' knowledge, this is the first reported case of chronic retinal detachment presenting with multiple peripheral macrocysts in a pediatric patient with Stickler's Syndrome. More research is needed into the cause and significance of retinal macrocysts, particularly in the pediatric population.

Recessive COL17A1 Mutations and a Dominant LAMB3 Mutation Cause Hypoplastic Amelogenesis Imperfecta.

Hereditary conditions that affect tooth enamel in quantity and/or quality are called amelogenesis imperfecta (AI). AI can occur as an isolated condition or as a symptom of a syndrome. An OMIM search with the term "AI" yielded 79 result entries. Mutations in the same gene cause syndromic or non-syndromic AI, depending on the nature of the mutations. In this study, we recruited two AI families and performed mutational analysis using whole-exome sequencing. The proband of family 1, with hypoplastic pitted AI and mild localized atopic dermatitis, had compound heterozygous COL17A1 mutations (paternal NM_000494.4: c.3598G>T, p.Asp1200Tyr and maternal c.1700G>A, p.Gly567Glu). The proband of family 2, with hypoplastic pitted AI and Jervell and Lange-Nielsen syndrome, had a recurrent LAMB3 mutation (NM_000228.3: c.3463_3475del, p.(Glu1155Thrfs*51)) in addition to compound heterozygous mutations in the KCNQ1 gene.

Expanding the genotype–phenotype correlations in Alport syndrome: novel mutations, digenic inheritance, and genetic modifiers

BackgroundAlport syndrome (AS) is the second most prevalent genetic cause of kidney failure, behind autosomal-dominant polycystic kidney disease, affecting at least one in 5000 individuals worldwide. AS is caused by COL4A3, COL4A4, and COL4A5 mutations. It is characterized as three distinct disorders of type IV collagen 3/4/5 based on a genetic evaluation: X-linked, autosomal, and digenic. About two-thirds of AS cases are X-linked (XLAS), 15% are autosomal recessive (ARAS), and 20% are autosomal dominant (ADAS). The spectrum of phenotypes associated with AS ranges from increasing renal disease with extrarenal abnormalities to isolated hematuria. Coinherited genetic mutations contribute significantly to clinical severity and variability.MethodsIn this study, an AS panel (COL4A3/COL4A4/COL4A5) and clinical exome sequencing (CES) were performed on 18 patients.ResultsNineteen specific AS mutations, including 15 novel mutations, were found in these 18 cases, which included 17 Turkish families and 1 Syrian family. Digenic inheritance was observed in one patient, and eight coinherited genetic mutations were discovered.ConclusionsThis research reveals many novel AS mutations and shows robust genotype–phenotype heterogeneity in the disease. The results expand the clinical and molecular scope of AS and clarify the ADAS and digenic AS phenotypes, further enhancing our understanding of the complex nature of AS and its association with genetic modifiers. The data broaden the spectrum of AS-related gene mutations and provide new insights on genotype–phenotype correlations in AS.

A Current Landscape on Alport Syndrome Cases: Characterization, Therapy and Management Perspectives.

Alport syndrome (AS) is a rare genetic disorder categorized by the progressive loss of kidney function, sensorineural hearing loss and eye abnormalities. It occurs due to mutations in three genes that encode for the alpha chains of type IV collagen. Globally, the disease is classified based on the pattern of inheritance into X-linked AS (XLAS), which is caused by pathogenic variants in COL4A5, representing 80% of AS. Autosomal recessive AS (ARAS), caused by mutations in either COL4A3 or COL4A4, represents 15% of AS. Autosomal dominant AS (ADAS) is rare and has been recorded in 5% of all cases due to mutations in COL4A3 or COL4A4. This review provides updated knowledge about AS including its clinical and genetic characteristics in addition to available therapies that only slow the progression of the disease. It also focuses on reported cases in Saudi Arabia and their prevalence. Moreover, we shed light on advances in genetic technologies like gene editing using CRISPR/Cas9 technology, the need for an early diagnosis of AS and managing the progression of the disease. Eventually, we provide a few recommendations for disease management, particularly in regions like Saudi Arabia where consanguineous marriages increase the risk.

Clinical and molecular features in a cohort of Middle Eastern patients with epidermolysis bullosa.

Epidermolysis bullosa (EB) features skin and mucosal fragility due to pathogenic variants in genes encoding components of the cutaneous basement membrane. Based on the level of separation within the dermal-epidermal junction, EB is sub-classified into four major types including EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB), and Kindler EB (KEB) with 16 EB-associated genes reported to date. We ascertained a cohort of 151 EB patients of various Middle Eastern ethnic backgrounds. The cohort was comprised of EBS (64%, 97/151), DEB (21%, 31/151), JEB (12%, 18/151), and KEB (3%, 5/151). KRT14 and KRT5 variants were most common among EBS patients with 43% (42/97) and 46% (45/97) of EBS patients carrying mutations in either of these two genes, respectively. Truncal involvement was more common in KRT14-associated EBS as compared to EBS due to KRT5 mutations (p < .05). Mutations in COL17A1 and laminin 332-encoding genes were identified in 55% (10/18) and 45% (8/18) of JEB patients. Scarring alopecia, caries, and EB nevi were most common among JEB patients carrying COL17A1 mutations as compared to laminin 332-associated JEB (p < .05). Abnormal nails were evident in most DEB and JEB patients while poikiloderma was exclusively observed in KEB (p < .001). EB patients of Middle Eastern origin were found to feature specific phenotype-genotype correlations of relevance to the diagnosis and genetic counseling of patients in this region.

Analysis of miRNAs in Osteogenesis imperfecta Caused by Mutations in COL1A1 and COL1A2: Insights into Molecular Mechanisms and Potential Therapeutic Targets.

Osteogenesis imperfecta (OI) is a group of connective tissue disorders leading to abnormal bone formation, mainly due to mutations in genes encoding collagen type I (Col I). Osteogenesis is regulated by a number of molecules, including microRNAs (miRNAs), indicating their potential as targets for OI therapy. The goal of this study was to identify and analyze the expression profiles of miRNAs involved in bone extracellular matrix (ECM) regulation in patients diagnosed with OI type I caused by mutations in COL1A1 or COL1A2. Primary skin fibroblast cultures were used for DNA purification and sequence analysis, followed by analysis of miRNA expression. Sequencing analysis revealed mutations of the COL1A1 or COL1A2 genes in all OI patients, including four previously unreported. Amongst the 40 miRNAs analyzed, 9 were identified exclusively in OI cells and 26 in both OI patients and the controls. In the latter case, the expression of six miRNAs (hsa-miR-10b-5p, hsa-miR-19a-3p, hsa-miR-19b-3p, has-miR-204-5p, has-miR-216a-5p, and hsa-miR-449a) increased, while four (hsa-miR-129-5p, hsa-miR-199b-5p, hsa-miR-664a-5p, and hsa-miR-30a-5p) decreased significantly in OI cells in comparison to their expression in the control cells. The identified mutations and miRNA expression profiles shed light on the intricate processes governing bone formation and ECM regulation, paving the way for further research and potential therapeutic advancements in OI and other genetic diseases related to bone abnormality management.

Epidermolysis bullosa with col7a1 mutation at Jiangsu university hospital: A Case report and review of the literature

We describe a case of a new born Chinese male baby who was diagnosed with Epidermolysis Bullosa (EB), a rare genetic skin illness that causes particular blisters to appear on the baby's lower limbs immediately after delivery. The flaw results from the skin's reduced ability to adhere to supporting tissue, which makes it brittle. Through carrier mother inheritance, genetic testing identified our case as an EB patient with Aplasia Cutis Congenita after a nucleotide alteration in the COL7A1 gene.

OP-03 Osteogenesis Imperfecta Type 3 with COL1A1 mutation Prenatal diagnosis and management

OP-03 Osteogenesis Imperfecta Type 3 with COL1A1 mutation Prenatal diagnosis and management

IPSC-derived type IV collagen α5-expressing kidney organoids model Alport syndrome

Alport syndrome (AS) is a hereditary glomerulonephritis caused by COL4A3, COL4A4 or COL4A5 gene mutations and characterized by abnormalities of glomerular basement membranes (GBMs). Due to a lack of curative treatments, the condition proceeds to end-stage renal disease even in adolescents. Hampering drug discovery is the absence of effective in vitro methods for testing the restoration of normal GBMs. Here, we aimed to develop kidney organoid models from AS patient iPSCs for this purpose. We established iPSC-derived collagen α5(IV)-expressing kidney organoids and confirmed that kidney organoids from COL4A5 mutation-corrected iPSCs restore collagen α5(IV) protein expression. Importantly, our model recapitulates the differences in collagen composition between iPSC-derived kidney organoids from mild and severe AS cases. Furthermore, we demonstrate that a chemical chaperone, 4-phenyl butyric acid, has the potential to correct GBM abnormalities in kidney organoids showing mild AS phenotypes. This iPSC-derived kidney organoid model will contribute to drug discovery for AS.

Combination of osteogenesis imperfecta and hypophosphatasia in three children with multiple fractures, low bone mass and severe osteomalacia, a challenge for therapeutic management

Osteogenesis imperfecta (OI) and hypophosphatasia (HPP) are rare skeletal disorders caused by mutations in the genes encoding collagen type I (COL1A, COL1A2) and tissue-non-specific isoenzyme of alkaline phosphatase (ALPL), respectively. Both conditions result in skeletal deformities and bone fragility although bone tissue abnormalities differ considerably. Children with OI have low bone mass and hypermineralized matrix, whereas HPP children develop rickets and osteomalacia.We report a family, father and three children, affected with growth retardation, low bone mass and recurrent fractures. None of them had rickets, blue sclera or dentinogenesis imperfecta. ALP serum levels were low and genetics revealed in the four probands heterozygous pathogenic mutations in COL1A2 c.838G > A (p.Gly280Ser) and in ALPL c.1333T > C (p.Ser445Pro). After multidisciplinary meeting, a diagnostic transiliac bone biopsy was indicated for each sibling for therapeutic decision.Bone histology and histomorphometry, as compared to reference values of children with OI type I as well as, to a control pediatric patient harboring the same COL1A2 mutation, revealed similarly decreased trabecular bone volume, increased osteocyte lacunae, but additionally severe osteomalacia. Quantitative backscattered electron imaging demonstrated that bone matrix mineralization was not as decreased as expected for osteomalacia.In summary, we observed within each biopsy samples classical features of OI and classical features of HPP. The apparent nearly normal bone mineralization density distribution results presumably from divergent effects of OI and HPP on matrix mineralization. A combination therapy was initiated with ALP enzyme-replacement and one month later with bisphosphonates. The ongoing treatment led to improved skeletal growth, increased BMD and markedly reduced fracture incidence.

Scoliosis in osteogenesis imperfecta: identifying the genetic and non-genetic factors affecting severity and progression from longitudinal data of 290 patients

BackgroundScoliosis is widely prevalent among osteogenesis imperfecta (OI) patients, and is progressive with age. However, factors affecting scoliosis in OI are not well known.MethodsWe retrospectively retrieved longitudinal radiographic and clinical records of consecutive OI patients seeking treatments at our hospital from 2014 to 2022, graded their pre-operative spinal conditions into four outcome groups, estimated their progression rates, and descriptively and inferentially analyzed the genetic and non-genetic factors that may affect the outcomes and progression rates.ResultsIn all, 290 OI patients met the inclusion criteria, where 221 had genetic records. Of these 221, about 2/3 had mutations in COL1A1 or COL1A2, followed by mutations in WNT1 (9.0%), IFITM5 (9.0%) and other OI risk genes. With an average age of 12.0 years (interquartile range [IQR] 6.9–16.1), 70.7% of the cohort had scoliosis (Cobb angle > 10°), including 106 (36.5%) mild (10°–25°), 40 (13.8%) moderate (25°–50°), and 59 (20.3%) severe (> 50°) scoliosis patients. Patients with either COL1A1 and COL1A2 were strongly biased toward having mild or no scoliosis, whereas patients with mutations in IFITM5, WNT1 and other recessive genes were more evenly distributed among the four outcome grades. Lower-limb discrepancy, bone mineral density (BMD) and age of first drug used were all significantly correlated with severity outcomes. Using multivariate logistic regression, we estimated that each year older adds an odds ratio of 1.13 (95% confidence interval [CI] 1.07–1.2) in progression into advanced stages of scoliosis. We estimated a cohort-wide progression rate of 2.7 degrees per year (95% CI 2.4–3.0). Early-onset patients experienced fast progressions during both infantile and adolescent stages. Twenty-five of the 59 (42.8%) patients with severe scoliosis underwent spinal surgeries, enjoying an average Cobb angle reduction of 33° (IQR 23–40) postoperatively.ConclusionThe severity and progression of scoliosis in osteogenesis imperfecta were affected by genetic factors including genotypes and mutation types, and non-genetic factors including age and BMD. As compared with COL1A1, mutations in COL1A2 were less damaging while those on IFITM5 and other recessive genes conferred damaging effects. Progression rates were the fastest in the adolescent adult age-group.

Inflammation-mediated fibroblast activation and immune dysregulation in collagen VII-deficient skin.

Inflammation is known to play a critical role in all stages of tumorigenesis; however, less is known about how it predisposes the tissue microenvironment preceding tumor formation. Recessive dystrophic epidermolysis bullosa (RDEB), a skin-blistering disease secondary to COL7A1 mutations and associated with chronic wounding, inflammation, fibrosis, and cutaneous squamous cell carcinoma (cSCC), models this dynamic. Here, we used single-cell RNA sequencing (scRNAseq) to analyze gene expression patterns in skin cells from a mouse model of RDEB. We uncovered a complex landscape within the RDEB dermal microenvironment that exhibited altered metabolism, enhanced angiogenesis, hyperproliferative keratinocytes, infiltration and activation of immune cell populations, and inflammatory fibroblast priming. We demonstrated the presence of activated neutrophil and Langerhans cell subpopulations and elevated expression of PD-1 and PD-L1 in T cells and antigen-presenting cells, respectively. Unsupervised clustering within the fibroblast population further revealed two differentiation pathways in RDEB fibroblasts, one toward myofibroblasts and the other toward a phenotype that shares the characteristics of inflammatory fibroblast subsets in other inflammatory diseases as well as the IL-1-induced inflammatory cancer-associated fibroblasts (iCAFs) reported in various cancer types. Quantitation of inflammatory cytokines indicated dynamic waves of IL-1α, TGF-β1, TNF, IL-6, and IFN-γ concentrations, along with dermal NF-κB activation preceding JAK/STAT signaling. We further demonstrated the divergent and overlapping roles of these cytokines in inducing inflammatory phenotypes in RDEB patients as well as RDEB mouse-derived fibroblasts together with their healthy controls. In summary, our data have suggested a potential role of inflammation, driven by the chronic release of inflammatory cytokines such as IL-1, in creating an immune-suppressed dermal microenvironment that underlies RDEB disease progression.

Identification of a novel COL7A1 variant associated with dystrophic epidermolysis bullosa pruriginosa responding effectively to dupilumab.

Variants in COL7A1 cause an extremely rare and clinically heterogeneous syndrome known as dystrophic epidermolysis bullosa pruriginosa (DEB-Pr). Duplilumab, a fully humanized anti-IL-4Ra monoclonal antibody, can inhibit IL-4 and IL-13-driven signaling. Ethical Compliance: Following our Institutional Review Board, genetic testing has been made available after completing a signed informed consent form. This article presents the case study of a DEB-Pr patient who received dupilumab therapy. Genomic DNA was extracted from the peripheral blood of the patient. The findings showed that a unique COL7A1 mutation was discovered in the patient who underwent genetic testing. As a result of the patient receiving dupilumab treatment, the individual reported experiencing significantly less itching and considerably improved erythema, less severe scales, crusts, and flattening of plaques. In conclusion, the current investigation showed that to the best of our knowledge, this is the first DEB-Pr patient with heterozygous COL7A1 (NM_000094.3:c.8110G>A [p. Gly2704Arg]) who responded positively to dupilumab treatment without experiencing any serious side effects.

The UCMD-Causing COL6A1 ( c . 930 + 189 C &gt; T ) Intron Mutation Leads to the Secretion and Aggregation of Single Mutated Collagen VI α1 Chains

Collagen VI is a unique member of the collagen family. Its assembly is a complex multistep process and the vulnerability of the process is manifested in muscular diseases. Mutations in COL6A1, COL6A2, and COL6A3 lead to the severe Ullrich Congenital Muscular Dystrophy (UCMD) and a spectrum of disease of varying severity including the milder Bethlem muscular dystrophy. The recently identified dominant intronic mutation in COL6A1 ( c . 930 + 189 C &gt; T ) leads to the partial in-frame insertion of a pseudoexon between exon 11 and exon 12. The pseudoexon is translated into 24 amino acid residues in the N-terminal region of the triple helix and results in the interruption of the typical G-X-Y motif. This recurrent de novo mutation leads to UCMD with a severe progression within the first decade of life. Here, we demonstrate that a mutation-specific antibody detects the mutant chain colocalizing with wild type collagen VI in the endomysium in patient muscle. Surprisingly, in the cell culture of patient dermal fibroblasts, the mutant chain is secreted as a single α chain, while in parallel, normal collagen VI tetramers are assembled with the wild-type α1 chain. The mutant chain cannot be incorporated into collagen VI tetramers but forms large aggregates in the extracellular matrix that may retain the ability to interact with collagen VI and potentially with other molecules. Also, α1 chain-deficient WI-26 VA4 cells transfected with the mutant α1 chain do not assemble collagen VI tetramers but, instead, form aggregates. Interestingly, both the wild type and the mutant single α1 chains form amorphous aggregates when expressed in HEK293 cells in the absence of α2 and α3 chains. The detection of aggregated, assembly incompetent, mutant collagen VI α1 chains provides novel insights into the disease pathophysiology of UCMD patients with the COL6A1 ( c . 930 + 189 C &gt; T ) mutation.

A novel mutation in COL1A1 causing osteogenesis imperfecta/hearing loss

ObjectivesTo screen the COL1A1 and COL1A2 gene mutation sites in a family with type I osteogenesis imperfecta (OI)/hearing loss and analyze the characteristics and recovery of hearing loss in patients with osteogenesis imperfecta. MethodsThe basic clinical data of OI proband and her parents were collected, and the COL1A1 and COL1A2 genes were detected in peripheral blood by PCR amplification and generation Sanger sequencing. Literature of stapedial surgery in patients with osteogenesis imperfecta was collected. ResultsThe heterozygous mutation of the 26 exon c.1922_1923 ins C in the OI progenitor COL1A1 gene led to the amino acid frameshift mutation of p.Pro 601FS, which was not detected in the phenotypic parents. The homozygous of exon 28 c.1782>G in COL1A2 was detected in the proband and her parents, resulting in changes in the protein p.Pro 549Ala. ConclusionThe clinical symptoms of the OI proband is caused by heterozygous mutation of the 26 exon c.1922_1923 ins C in COL1A1 gene. Stapedial surgery can provide short-term and long-term hearing benefits for OI patients with hearing loss. Level of evidenceLevel 4.

Temporal Progression of Aortic Valve Pathogenesis in a Mouse Model of Osteogenesis Imperfecta.

Organization of extracellular matrix (ECM) components, including collagens, proteoglycans, and elastin, is essential for maintaining the structure and function of heart valves throughout life. Mutations in ECM genes cause connective tissue disorders, including Osteogenesis Imperfecta (OI), and progressive debilitating heart valve dysfunction is common in these patients. Despite this, effective treatment options are limited to end-stage interventions. Mice with a homozygous frameshift mutation in col1a2 serve as a murine model of OI (oim/oim), and therefore, they were used in this study to examine the pathobiology of aortic valve (AoV) disease in this patient population at structural, functional, and molecular levels. Temporal echocardiography of oim/oim mice revealed AoV dysfunction by the late stages of disease in 12-month-old mice. However, structural and proteomic changes were apparent much earlier, at 3 months of age, and were associated with disturbances in ECM homeostasis primarily related to collagen and proteoglycan abnormalities and disorganization. Together, findings from this study provide insights into the underpinnings of late onset AoV dysfunction in connective tissue disease patients that can be used for the development of mechanistic-based therapies administered early to halt progression, thereby avoiding late-stage surgical intervention.

Novel nonsense mutation in COL4A4 associated with Alport syndrome

Mutations are the major cause of genetic disorders. Development of next generation sequencing techniques have played a vital role in the identification of mutations in the patients which help us to relate specific mutations to various disorders. In an effort to identify and correlate mutations to Alport syndrome, whole exome sequencing and Sanger sequencing were carried out in a family having significant family history of Alport syndrome on maternal side. Since mutations in collagen encoding genes, especially COL4A3, COL4A4 and COL4A5 are known to cause Alport syndrome, various in-silico tools were used to screen for deleterious mutations in these genes. Here we report a novel mutation in COL4A4, Lys1688 to stop gain mutation in the patient. Analysis of the mutation using various databases revealed that this mutation occurs in a highly conserved region of COL4A4 protein and also it is predicted to be deleterious. Structural analysis and comparison of the mutant protein with wild type protein using in-silico tools also predict that the mutant protein has loss of function and could lead to the pathophysiology of the Alport syndrome.

Clinical features and morphology of collagen fibrils in patients with vascular Ehlers-Danlos based on electron microscopy.

Background: Vascular-type Ehlers-Danlos syndrome (vEDS) is caused by collagen III deficit resulting from heterogeneous mutations in COL3A1, which occasionally causes sudden death due to arterial/visceral rupture. However, it is difficult to conduct basic research on the pathophysiology of vEDS. Moreover, the number of patients with vEDS is small, limiting the number of available samples. Furthermore, the symptoms of vEDS may vary among family members, even if they share the same mutation. Accordingly, many aspects of the pathology of vEDS remain unknown. Therefore, we investigated the structural abnormalities in collagen fibrils and endoplasmic reticulum (ER) stress in skin samples using electron microscopy as well as their relationship with clinical symptoms in 30 patients with vEDS (vEDS group) and 48 patients without vEDS (disease-negative control group). Methods: Differences between the two groups were evaluated in terms of the sizes of collagen fibrils using coefficient of variation (COV). Results: COV was found to be significantly higher in the vEDS group than in the disease-negative control group, indicating irregularity in the size of collagen fibrils. However, in the vEDS group, some patients had low COV and seldom experienced serious complications and ER stress. Conclusion: ER stress might affect collagen fibril-composing proteins. Moreover, as this stress varies among people based on environmental factors and aging, it may be the underlying cause of varying vEDS symptoms.