Pathophysiology and Therapeutics of Thoracic Aortic Aneurysm in Marfan Syndrome

About 20% of individuals afflicted with thoracic aortic disease have single-gene mutations that predispose the vessel to aneurysm formation and/or acute aortic dissection often without associated syndromic features. One widely studied exception is Marfan syndrome (MFS) in which mutations in the extracellular protein fibrillin-1 cause additional abnormalities in the heart, eyes, and skeleton. Mouse models of MFS have been instrumental in delineating major cellular and molecular determinants of thoracic aortic disease. In spite of research efforts, translating experimental findings from MFS mice into effective drug therapies for MFS patients remains an unfulfilled promise. Here, we describe a series of studies that have implicated endothelial dysfunction and improper angiotensin II and TGFβ signaling in driving thoracic aortic disease in MFS mice. We also discuss how these investigations have influenced the way we conceptualized possible new therapies to slow down or even halt aneurysm progression in this relatively common connective tissue disorder.

Osteopetrosis in a Patient of Systemic Sclerosis Sine Scleroderma: A Rare Association

Systemic sclerosis is a connective tissue disorder of unknown etiology. Although it is a multisystemic disorder, skin thickening is considered as a hallmark of the disease. It usually involves the lungs, gastrointestinal, and musculoskeletal systems. However, a rare subset of systemic sclerosis, systemic sclerosis sine scleroderma, is characterized by internal organ involvement and positive serologic markers with the total or partial absence of cutaneous manifestations. We present a rare association of osteopetrosis in a case of systemic sclerosis sine scleroderma, in a 22-year-old male patient, who presented with pulmonary symptoms as his chief complaints, unreported so far in literature.

Role of Fibroblasts and Myofibroblasts on the Pathogenesis and Treatment of Pelvic Organ Prolapse

Pelvic organ prolapse (POP) is a multifactorial connective tissue disorder caused by damage to the supportive structures of the pelvic floor, leading to the descent of pelvic organs in the vagina. In women with POP, fibroblast function is disturbed or altered, which causes impaired collagen metabolism that affects the mechanical properties of the tissue. Ideal surgical repair, either native tissue repair or POP surgery using an implant, aims to create a functional pelvic floor that is load-bearing, activating fibroblasts to regulate collagen metabolism without creating fibrotic tissue. Fibroblast function plays a crucial role in the pathophysiology of POP by directly affecting the connective tissue quality. On the other hand, fibroblasts determine the success of the POP treatment, as the fibroblast-to-(myo)fibroblast transition is the key event during wound healing and tissue repair. In this review, we aim to resolve the question of “cause and result” for the fibroblasts in the development and treatment of POP. This review may contribute to preventing the development and progress of anatomical abnormalities involved in POP and to optimizing surgical outcomes.

Combination of osteogenesis imperfecta and type 1 diabetes mellitus

Osteogenesis imperfecta (OI) is a hereditary connective tissue disorder accompanied by increased bone fragility. Five types of OI are distinguished on the basis of phenotypic manifestations. OI type 1 is characterized by a reduced amount of normal type 1 collagen and is the mildest form. In addition to the fractures, course of disease can be accompanied by short stature, skeletal deformity and joint hypermobility. Although fracture risk decreases with age, such patients needs regular follow-up with an assessment of bone mineral density (BMD) and, if necessary, correction of therapy to improve the quality of life. Type 1 diabetes mellitus (T1DM) is associated with a decreased BMD, which is mostly attributed to insulin deficiency and hyperglycemia, which also increase the risk of fractures. Achieving and stable maintenance of glycemic targets is often challenging, but it is necessary to exclude hyperglycemia as a factor that further worsens the quality of bone. This paper describes a clinical case of an extremely rare combination of type 1 OI and T1DM, two diseases with a pronounced negative effect on bone tissue. The combination of these pathologies requires special management tactics for such patients to reduce the risk of developing new fractures.

Diagnosis of a Von Willebrand type 2N disease in a patient with a connective tissue disorder close to Ehlers-Danlos syndrome

Ehlers Danlos Syndrome est souvent associé à une tendance accrue aux saignements et il peut être aussi associé à des troubles de l’hémostase qui vont aggraver la tendance hémorragique du patient. Nous rapportons le cas d’un patient suivi pour un trouble autosomale récessif des tissus conjonctifs dont le phénotype dermatologique est proche d’Ehlers Danlos Syndrome. L’exploration de l’hémostase chez ce patient révèle un type 2N de la maladie de Von Willebrand.

Cardiovascular and connective tissue disorder features in FLNA-related PVNH patients: progress towards a refined delineation of this syndrome

Background FLNA Loss-of-Function (LoF) causes periventricular nodular heterotopia type 1 (PVNH1), an acknowledged cause of seizures of various types. Neurological symptoms are inconstant, and cardiovascular (CV) defects or connective tissue disorders (CTD) have regularly been associated. We aimed at refining the description of CV and CTD features in patients with FLNA LoF and depicting the multisystemic nature of this condition. Methods We retrospectively evaluated FLNA variants and clinical presentations in FLNA LoF patient with at least one CV or CTD feature, from three cohorts: ten patients from the French Reference Center for Rare Vascular Diseases, 23 patients from the national reference diagnostic lab for filaminopathies-A, and 59 patients from literature review. Results Half of patients did not present neurological symptoms. Most patients presented a syndromic association combining CV and CTD features. CV anomalies, mostly aortic aneurysm and/or dilation were present in 75% of patients. CTD features were present in 75%. Variants analysis demonstrated an enrichment of coding variants in the CH1 domain of FLNA protein. Conclusion In FLNA LoF patients, the absence of seizures should not be overlooked. When considering a diagnosis of PVNH1, the assessment for CV and CTD anomalies is of major interest as they represent interlinked features. We recommend systematic study of FLNA within CTD genes panels, regardless of the presence of neurological symptoms.

Gonosomal Mosaicism for a Novel COL5A1 Pathogenic Variant in Classic Ehlers-Danlos Syndrome

(1) Background: Classic Ehlers-Danlos syndrome (cEDS) is a heritable connective tissue disorder characterized by joint hypermobility and skin hyperextensibility with atrophic scarring. Many cEDS individuals carry variants in either the COL5A1 or COL5A2 genes. Mosaicism is relatively common in heritable connective tissue disorders but is rare in EDS. In cEDS, a single example of presumed gonosomal mosaicism for a COL5A1 variant has been published to date. (2) Methods: An 8-year-old girl with cEDS was analyzed by next-generation sequencing (NGS). Segregation was performed by Sanger sequencing in her unaffected parents. In the father, the mosaicism of the variant was further analyzed by targeted NGS and droplet digital PCR (ddPCR) in the blood and by Sanger sequencing in other tissues. (3) Results: The NGS analysis revealed the novel germline heterozygous COL5A1 c.1369G>T, p.(Glu457*) variant in the proband. Sanger chromatogram of the father’s blood specimen suggested the presence of a low-level mosaicism for the COL5A1 variant, which was confirmed by NGS and estimated to be 4.8% by ddPCR. The mosaicism was also confirmed by Sanger sequencing in the father’s saliva, hair bulbs and nails. (4) Conclusions: We described the second case of cEDS caused by paternal gonosomal mosaicism in COL5A1. Parental mosaicism could be an issue in cEDS and, therefore, considered for appropriate genetic counseling.

P066 Orthopedic complications of osteogenesis imperfecta

Background Osteogenesis imperfecta (OI) is an inherited connective tissue disorder including various skeletal manifestations. Bone fragility, vertebral body malformation and length lower limbs inequality are often responsible for orthopedic complications. The aim of our study was to determine orthopedic complications of OI and to specify management modalities in rheumatology. Methods We conduct a retrospective study based on the files of children referred to the rheumatology departement over the last 15 years, for treatment of OI. The evaluation was clinical and radiological. Clinical examination included joint and spine assessment. An X-ray of the spine and painful joints associated with a quantitative densitometry were requested. Results Five patients were collected, their mean age was 9 years. All patients had peripheral fracture. Joint assessment revealed a flessum of the elbow and a reduction of the motion of hip in 40% of cases. Scoliosis was noted also in 40% of cases. The average of spine Z –score was -3, 4. All children had benefited from oral calcium and vitamin D supplementation associated with cyclic intravenous bisphosphonates and an adapted rehabilitation protocol. Surgical management was often needed in 2 cases. Discussion and Conclusion Orthopedic complications during OI are essentially the consequence of lower bone mineral density which would cause peripheral or vertebral fracture. Indeed, some other factors like length inequality, pelvic obliquity, ligamentous laxity and inter-vertebral disc abnormalities could be involved in scoliotic progression. The management of these skeletal complications must be early and multidisciplinary in order to improve the prognosis and the quality of life of the patient