Connective Tissue Manifestations Research Articles

Variable clinical expression of a Belgian TGFB3 founder variant suggests the presence of a genetic modifier.

Background: TGFB3 variants cause Loeys-Dietz syndrome type 5, a syndromic form of thoracic aortic aneurysm and dissection. The exact disease phenotype is hard to delineate because of few identified cases and highly variable clinical representation. Methodology: We provide the results of a haplotype analysis and a medical record review of clinical features of 27 individuals from 5 different families, originating from the Campine region in Flanders, carrying the NM_003239.5(TGFB3):c.787G>C p.(Asp263His) likely pathogenic variant, dbSNP:rs796051886, ClinVar:203492. The Asp263 residue is essential for integrin binding to the Arg-Gly-Asp (RGD) motif of the TGFβ3-cytokine. Results: The haplotype analysis revealed a shared haplotype of minimum 1.92Mb and maximum 4.14Mb, suggesting a common founder originating >400years ago. Variable clinical features included connective tissue manifestations, non-aneurysmal cardiovascular problems such as hypertrophic cardiomyopathy, bicuspid aortic valve, mitral valve disease, and septal defects. Remarkably, only in 4 out of the 27 variant-harboring individuals, significant aortic involvement was observed. In one family, a 31-year-old male presented with type A dissection. In another family, the male proband (65years) underwent a Bentall procedure because of bicuspid aortic valve insufficiency combined with sinus of Valsalva of 50mm, while an 80-year-old male relative had an aortic diameter of 43mm. In a third family, the father of the proband (75years) presented with ascending aortic aneurysm (44mm). Conclusion: The low penetrance (15%) of aortic aneurysm/dissection suggests that haploinsufficiency alone by the TGFB3 variant may not result in aneurysm development but that additional factors are required to provoke the aneurysm phenotype.

Emerging mechanisms of elastin transcriptional regulation.

Elastin provides recoil to tissues that stretch such as the lung, blood vessels, and skin. It is deposited in a brief window starting in the prenatal period and extending to adolescence in vertebrates, and then slowly turns over. Elastin insufficiency is seen in conditions such as Williams-Beuren syndrome and elastin-related supravalvar aortic stenosis, which are associated with a range of vascular and connective tissue manifestations. Regulation of the elastin (ELN) gene occurs at multiple levels including promoter activation/inhibition, mRNA stability, interaction with microRNAs, and alternative splicing. However, these mechanisms are incompletely understood. Better understanding of the processes controlling ELN gene expression may improve medicine's ability to intervene in these rare conditions, as well as to replace age-associated losses by re-initiating elastin production. This review describes what is known about the ELN gene promoter structure, transcriptional regulation by cytokines and transcription factors, and posttranscriptional regulation via mRNA stability and micro-RNA and highlights new approaches that may influence regenerative medicine.

Expanding the phenotype of ATP6AP1 deficiency.

Vacuolar ATPases (V-ATPases) are large multisubunit proton pumps conserved among all eukaryotic cells that are involved in diverse functions including acidification of membrane-bound intracellular compartments. The ATP6AP1 gene encodes an accessory subunit of the vacuolar (V)-ATPase protein pump. Pathogenic variants in ATP6AP1 have been described in association with a congenital disorder of glycosylation (CDG), which are highly variable, but often characterized by immunodeficiency, hepatopathy, and neurologic manifestations. Although the most striking and common clinical feature is hepatopathy, the phenotypic and genotypic spectrum of ATP6AP1-CDG continues to expand. Here, we report identical twins who presented with acute liver failure and jaundice. Prenatal features included cystic hygroma, atrial septal defect, and ventriculomegaly. Postnatal features included pectus carinatum, connective tissue abnormalities, and hypospadias. Whole-exome sequencing (WES) revealed a novel de novo in-frame deletion in the ATP6AP1 gene (c.230_232delACT;p.Tyr77del). Although both twins have the commonly reported clinical feature of hepatopathy seen in other individuals with ATP6AP1-CDG-related disorder, they do not have neurological sequelae. This report expands the phenotypic spectrum of ATP6AP1-CDG-related disorder with both probands exhibiting unique prenatal and postnatal features, including fetal ventriculomegaly, umbilical hernia, pectus carinatum, micropenis, and hypospadias. Furthermore, this case affirms that neurological features described in the initial case series on ATP6AP1-CDG do not appear to be central, whereas the prenatal and connective tissue manifestations may be more common than previously thought. This emphasizes the importance of long-term clinical follow-up and variant interpretation using current updated recommendations.

Low penetrance COL5A1 variants in a young patient with intracranial aneurysm and very mild signs of Ehlers-Danlos syndrome

Spontaneous cervical artery dissection (CeAD) is a major cause of ischemic stroke in young adults, whose genetic susceptibility factors are still largely unknown. Nevertheless, subtle ultrastructural connective tissue alterations (especially in the collagen fibril morphology) are recognized in a large proportion of CeAD patients, in which recent genetic investigations reported an enrichment of variants in genes associated with known connective tissue disorders. In this regard, COL5A1 variants have been reported in a small subset of CeAD patients, with or without classical Ehlers-Danlos syndrome (cEDS) features.We investigated a 22-year-old patient with intracranial aneurysm and mild connective tissue manifestations reminiscent of EDS. Whole-exome sequencing identified two COL5A1 missense variants in trans configuration: NM_000093.5:c.[1588G>A];[4135C>T], NP_000084.3:p.[(Gly530Ser)];[(Pro1379Ser)]. Functional assays demonstrated a significant decrease of collagen α1(V) chain expression in both heterozygous parents compared to control cells, and an additive effect of these two variants in the proband. Interestingly, both parents manifested very subtle EDS signs, such as atrophic scars, recurrent bone fractures, colonic diverticulosis, varicose veins, and osteoarthritis.Our findings emphasize the involvement of COL5A1 in the predisposition to vascular phenotypes and provide novel insights on the c.1588G>A variant, whose functional significance has not been definitely established. In fact, it was previously reported as both “disease modifying”, and as a biallelic causative mutation (with heterozygous individuals showing subtle clinical signs of cEDS). We speculated that the c.1588G>A variant might lead to overt phenotype in combination with additional genetic “hits” lowering the collagen α1(V) chain expression below a hypothetical disease threshold.

Rare Co-occurrence of Beta-Thalassemia and Pseudoxanthoma elasticum: Novel Biomolecular Findings.

A number of beta-thalassemia patients, independently from the type of beta-thalassemia (β0 or β+) and blood transfusion requirements, may develop, after puberty, dermal, cardiovascular, and ocular complications associated with an ectopic mineralization phenotype similar to that observed in another rare genetic disorder, namely, Pseudoxanthoma elasticum (PXE). To date, the causes of these alterations in beta-thalassemia patients are not known, but it has been suggested that they could be the consequence of oxidative stress-driven epigenetic regulatory mechanisms producing an ABCC6 down-regulation. Since, in the last years, several genes have been associated to the ectopic mineralization phenotype, this study, for the first time, applied, on beta-thalassemia patients with ectopic mineralization phenotype, a multigene testing strategy. Selection of genes to be analyzed was done on the basis of (i) their genetic involvement in calcification diseases or (ii) their role in calcium-phosphate equilibrium. Although, due to the rarity of these conditions, a limited number of patients was analyzed, the detection of pathogenic variants represents the proof of concept that PXE and beta-thalassemia traits co-occur on a genetic basis and that, in addition to causative mutations, functional polymorphisms may further influence connective tissue manifestations. The use of a multigene-based next-generation sequencing represents a useful time- and cost-effective approach, allowing to identify sequence variants that might improve prognostic assessment and better management of these patients, especially in the current era of precision medicine aiming to identify individual optimal care based on a unique personal profile.

Bilateral Distal Humeral Fracture in a patient with Osteogenesis imperfecta During the Covid Pandemic– A Rare Case Report

Introduction: Osteogenesis imperfecta (OI) is a genetic disorder which is characterised by bone deformity, low bone mass, connective tissue manifestations and brittle bones with history of multiple fractures. Although recurrent fractures are known in patient with OI, the occurrence of bilateral simultaneous fracture of humerus is quite rare. Presenting complaint and investigations: The patient had a fall in the outdoors during a storm during the height of covid pandemic and sustained injury to both arms. Radiographs revealed comminuted fracture of left distal humerus and transverse extraarticular supracondylar fracture of right humerus. Diagnoses, therapeutics interventions, and outcomes: Although, conservative measures were advised as per the guidelines for orthopaedic surgery during the covid pandemic for most of the fractures, the decision to operate was made considering the morbid obesity and hampered mobility due to bilateral above elbow plaster.The patient underwent staged open reduction and internal fixation of both distal humerus with anatomical locking plates in a span of 2 weeks. She recovered uneventfully with a good functional range of movements and resumed her routine activities. Conclusion: The treatment for complex and unusual fractures should be individualised and should take into consideration of patient’s general condition and safety.

Osteogenesis imperfecta: advancements in genetics and treatment.

The purpose of this review is to outline the current understanding of the molecular mechanisms and natural history of osteogenesis imperfecta, and to describe the development of new treatments for this disorder. The introduction of next-generation sequencing technology has led to better understanding of the genetic cause of osteogenesis imperfecta and enabled cost-effective and timely diagnosis via expanded gene panels and exome or genome sequencing. Clinically, despite genetic heterogeneity, different forms of osteogenesis imperfecta share similar features that include connective tissue and systemic manifestations in addition to bone fragility. Thus, the goals of treatment in osteogenesis imperfecta extend beyond decreasing the risk of fracture, to include the maximization of growth and mobility, and the management of extraskeletal complications. The standard of care in pediatric patients is bisphosphonates therapy. Ongoing preclinical studies in osteogenesis imperfecta mouse models and clinical studies in individuals with osteogenesis imperfecta have been instrumental in the development of new and targeted therapeutic approaches, such as sclerostin inhibition and transforming growth factor-β inhibition. Osteogenesis imperfecta is a skeletal dysplasia characterized by bone fragility and extraskeletal manifestations. Better understanding of the mechanisms of osteogenesis imperfecta will enable the development of much needed targeted therapies to improve the outcome in affected individuals.

FLNA mutations in surviving males presenting with connective tissue findings: two new case reports and review of the literature

BackgroundMutations in the X-linked gene filamin A (FLNA), encoding the actin-binding protein FLNA, cause a wide spectrum of connective tissue, skeletal, cardiovascular and/or gastrointestinal manifestations. Males are typically more severely affected than females with common pre- or perinatal death.Case presentationWe provide a genotype- and phenotype-oriented literature overview of FLNA hemizygous mutations and report on two live-born male FLNA mutation carriers. Firstly, we identified a de novo, missense mutation (c.238C > G, p.(Leu80Val)) in a five-year old Indian boy who presented with periventricular nodular heterotopia, increased skin laxity, joint hypermobility, mitral valve prolapse with regurgitation and marked facial features (e.g. a flat face, orbital fullness, upslanting palpebral fissures and low-set ears). Secondly, we identified two cis-located FLNA mutations (c.7921C > G, p.(Pro2641Ala); c.7923delC, p.(Tyr2642Thrfs*63)) in a Bosnian patient with Ehlers-Danlos syndrome-like features such as skin translucency and joint hypermobility. This patient also presented with brain anomalies, pectus excavatum, mitral valve prolapse, pulmonary hypertension and dilatation of the pulmonary arteries. He died from heart failure in his second year of life.ConclusionsThese two new cases expand the list of live-born FLNA mutation-positive males with connective tissue disease from eight to ten, contributing to a better knowledge of the genetic and phenotypic spectrum of FLNA-related disease.

Variantes que mantienen el marco de lectura en el dominio Rod 1 proximal del gen FLNA se asocian con un predominio del fenotipo valvular

Introduction and objectivesX-linked cardiac valvular dysplasia is a rare form of male-specific congenital heart defect mainly characterized by myxomatous degeneration of the atrioventricular valves with variable hemodynamic consequences. It is caused by genetic defects in FLNA-encoded filamin A, a widely expressed actin-binding protein that regulates cytoskeleton organization. Filamin A loss of function has also been associated with often concurring neurologic and connective tissue manifestations, with mutations in the first half of the Rod 1 domain apparently expressing the full cardiac phenotype. We contribute to previous genotype-phenotype correlations with a multidisciplinary approach in a newly-described family. MethodsCardiologic, dysmorphologic, and genetic evaluation of available members were complemented with transcriptional and X-chromosome inactivation studies. ResultsA novel FLNA mutation c.1066-3C>G cosegregated with a male-expressed, apparently isolated, cardiac phenotype with no skewed X-inactivation pattern in female carriers. This variant was shown to result in an in-frame deletion of 8 amino acid residues near the N-terminal region of the protein. ConclusionsA nonimprinted, partial loss of function of filamin A proximal Rod 1 domain seems to be the pathogenetic mechanism of cardiac valvular dysplasia, with some cases occasionally expressing associated extracardiac manifestations.Full English text available from: www.revespcardiol.org/en

In-frame Variants in FLNA Proximal Rod 1 Domain Associate With a Predominant Cardiac Valvular Phenotype

Introduction and objectivesX-linked cardiac valvular dysplasia is a rare form of male-specific congenital heart defect mainly characterized by myxomatous degeneration of the atrioventricular valves with variable hemodynamic consequences. It is caused by genetic defects in FLNA-encoded filamin A, a widely expressed actin-binding protein that regulates cytoskeleton organization. Filamin A loss of function has also been associated with often concurring neurologic and connective tissue manifestations, with mutations in the first half of the Rod 1 domain apparently expressing the full cardiac phenotype. We contribute to previous genotype-phenotype correlations with a multidisciplinary approach in a newly-described family. MethodsCardiologic, dysmorphologic, and genetic evaluation of available members were complemented with transcriptional and X-chromosome inactivation studies. ResultsA novel FLNA mutation c.1066-3C>G cosegregated with a male-expressed, apparently isolated, cardiac phenotype with no skewed X-inactivation pattern in female carriers. This variant was shown to result in an in-frame deletion of 8 amino acid residues near the N-terminal region of the protein. ConclusionsA nonimprinted, partial loss of function of filamin A proximal Rod 1 domain seems to be the pathogenetic mechanism of cardiac valvular dysplasia, with some cases occasionally expressing associated extracardiac manifestations.

Genetic causes and mechanisms of Osteogenesis Imperfecta

Osteogenesis Imperfecta (OI) is a genetic disorder characterized by various clinical features including bone deformities, low bone mass, brittle bones, and connective tissue manifestations. The predominant cause of OI is due to mutations in the two genes that encode type I collagen. However, recent advances in sequencing technology has led to the discovery of novel genes that are implicated in recessive and dominant OI. These include genes that regulate the post-translational modification, secretion and processing of type I collagen as well as those required for osteoblast differentiation and bone mineralization. As such, OI has become a spectrum of genetic disorders informing about the determinants of both bone quantity and quality. Here we summarize the known genetic causes of OI, animal models that recapitulate the human disease and mechanisms that underlie disease pathogenesis. Additionally, we discuss the effects of disrupted collagen networks on extracellular matrix signaling and its impact on disease progression.

Cutaneous and ocular manifestations of neurocutaneous syndromes

Neurocutaneous syndromes are a heterogeneous group of congenital and hereditary disorders with manifestations in the skin and the nervous system, usually together with ocular features that represent diagnostic clues and potential sources of morbidity. Dermatologists and ophthalmologists often need to work together in identifying and managing patients with these conditions; herein, we focus on classic and under-recognized neurocutaneous syndromes. We begin with autosomal dominant genodermatoses characterized by hamartomas and tumors in the skin, eyes, and central nervous system: neurofibromatosis type 1, tuberous sclerosis complex, and PTEN hamartoma-tumor syndrome. This is followed by a discussion of two mosaic disorders, Sturge-Weber syndrome and neurocutaneous melanocytosis. In addition to providing an update on clinical presentations and evaluation of patients with these conditions, we review recent insights into their pathogenesis, drawing attention to relationships among the diseases on a molecular level and implications regarding treatment. We also highlight the major features of other neurocutaneous syndromes that have ocular findings plus pigmentary, vascular, hyperkeratotic, adnexal, connective tissue, photosensitive, and inflammatory manifestations in the skin.

Identification of fibrillin 1 gene mutations in patients with bicuspid aortic valve (BAV) without Marfan syndrome

BackgroundBicuspid aortic valve (BAV) is the most frequent congenital heart disease with frequent involvement in thoracic aortic dilatation, aneurysm and dissection. Although BAV and Marfan syndrome (MFS) share some clinical features, and some MFS patients with BAV display mutations in FBN1, the gene encoding fibrillin-1, the genetic background of isolated BAV is poorly defined.MethodsTen consecutive BAV patients [8 men, age range 24–42 years] without MFS were clinically characterized. BAV phenotype and function, together with evaluation of aortic morphology, were comprehensively assessed by Doppler echocardiography. Direct sequencing of each FBN1 exon with flanking intron sequences was performed on eight patients.ResultsWe detected three FBN1 mutations in two patients (aged 24 and 25 years) displaying aortic root aneurysm ≥50 mm and moderate aortic regurgitation. In particular, one patient had two mutations (p.Arg2726Trp and p.Arg636Gly) one of which has been previously associated with variable Marfanoid phenotypes. The other patient showed a pArg529Gln substitution reported to be associated with an incomplete MFS phenotype.ConclusionsThe present findings enlarge the clinical spectrum of isolated BAV to include patients with BAV without MFS who have involvement of FBN1 gene. These results underscore the importance of accurate phenotyping of BAV aortopathy and of clinical characterization of BAV patients, including investigation of systemic connective tissue manifestations and genetic testing.

Living Donor Liver Transplantation for an Infant with Osteogenesis Imperfecta and Intrahepatic Cholestasis: Report of a Case

Osteogenesis imperfecta (OI) is a group of genetic disorders characterized by bone fragility and connective tissue manifestations. We report a successful liver transplantation (LT) in an 8-month-old boy with OI and cholestatic biliary cirrhosis. After 4 cycles of intravenous pamidronate, LT was performed under intravenous anesthesia using a left lateral section from his mother without mechanical retractors. The operation time was 420 min and estimated blood loss was 520 mL requiring one unit of RBC transfusion. He was discharged without surgical complications. Therefore, LT should be considered for patients with end stage liver disease and OI under organic multidisciplinary cooperation.

Severe eczema and Hyper-IgE in Loeys–Dietz-syndrome — Contribution to new findings of immune dysregulation in connective tissue disorders

Loeys-Dietz syndrome (LDS) is a connective tissue disorder caused by monoallelic mutations in TGFBR1 and TGFBR2, which encode for subunits of the transforming growth factor beta (TGFβ) receptor. Affected patients are identified by vascular aneurysms with tortuosity and distinct morphological presentations similar to Marfan syndrome; however, an additional predisposition towards asthma and allergy has recently been found. We describe two patients with a novel missense mutation in TGFBR1 presenting with highly elevated levels of IgE and severe eczema similar to autosomal-dominant Hyper-IgE syndrome (HIES). Mild allergic manifestations with normal up to moderately increased IgE were observed in 3 out of 6 additional LDS patients. A comparison of this cohort with 4 HIES patients illustrates the significant overlap of both syndromes including eczema and elevated IgE as well as skeletal and connective tissue manifestations.

Diagnostic approach to the hyper-IgE syndromes: Immunologic and clinical key findings to differentiate hyper-IgE syndromes from atopic dermatitis

Hyper-IgE syndromes (HIES) are primary immunodeficiency disorders characterized by Staphylococcus aureus abscesses, recurrent pneumonia, increased serum IgE levels, and eczema. The association of heterozygous signal transducer and activator of transcription 3 (STAT3) mutations with autosomal dominant (AD)-HIES allows the differentiation of AD-HIES from disorders associated with eczema and increased serum IgE levels, such as other primary immunodeficiencies and atopic dermatitis. To facilitate early diagnosis of AD-HIES to initiate appropriate therapy. The clinical phenotype (suggested by a National Institutes of Health [NIH] score of >or=40 points), STAT3 genotype, and T(H)17 cell counts were compared in a cohort of 78 patients suspected of having HIES. Heterozygous STAT3 missense mutations and in-frame deletions were identified in 48 patients, all but 2 with an NIH score >or=40 points. Patients with STAT3 mutations with HIES showed significantly lower T(H)17 cell counts compared with patients with wild-type STAT3 and control subjects. Only 1 patient with wild-type STAT3 had both an NIH score >or=40 points and abnormal T(H)17 cell counts (<or=0.2% of CD4(+) cells), with this exception being identified with a homozygous dedicator of cytogenesis 8 protein (DOCK8) mutation. Pathologic shedding of primary teeth was present in 3 patients with wild-type STAT3 and 33 patients with STAT3 mutations. Internal abscesses and severe infections were exclusively seen in patients with STAT3 mutations, who also had increased pneumatocele formation and skeletal or connective tissue manifestations compared with patients with wild-type STAT3. We expanded the number of STAT3 mutations and validated that the NIH score sensitively identifies patients with HIES. Based on our patient cohort, we propose key findings that, when combined with T(H)17 cell numbers, predict patients with AD-HIES with STAT3 mutations, supporting early diagnosis of AD-HIES.

The Thyrocyte-Fibrocyte Link: Closing the Loop in the Pathogenesis of Graves’ Disease?

Graves’ disease (GD) is an antibody-driven autoimmune process affecting the thyroid gland and extrathyroidal target tissues in roughly 90% of the cases (1). Generation of activating autoantibodies against the TSH receptor (TSHR) leads to excessive thyroid hormone synthesis uniquely in GD (2).However, themechanismsunderlyingextrathyroidal tissue inflammation and remodeling remain uncertain, as does their relationshipwith theprocessesoccurring in the thyroid. Manifestations of GD include thyrotoxicosis and several extrathyroidal signs including Graves’ orbitopathy (GO), dermopathy, and acropachy (3). GO and dermopathy are connective tissue manifestations of GD. Tissue remodeling is a prominent feature of both and is apparently controlled by adaptive T cells. Lymphocytes and other bone marrow-derived cells recruited into the orbit appear to be the major effectors of autoagressive tissue destruction in GO. The most likely sequence of events is that T cells infiltrate the orbital and dermal connective tissue and respond to a depot of orbital/dermal autoantigens that display an identical structure to have epitopes that cross-react with a thyroid autoantigen (1–3). Orbital fibroblasts comprise a heterogeneous population of cells possessing divergent phenotypes and potential for differentiation. They represent a bimodal population of cells with regard to the surface display of the glycoprotein, Thy1. Moreover, they exhibit attributes differing from their nonorbital counterparts that may underlie anatomic-selective involvement of the orbit in GD (4). Thus, orbital fibroblasts exhibit a unique phenotype, including exaggerated responses to proinflammatory cytokines. Cytokines play a key role in the development of the extrathyroidal manifestations of GD. These molecules are produced in the orbit of GO patients by infiltrating inflammatory cells as well as orbital fibroblasts. Cytokines can modulate the immune reaction in GO by increasing major histocompatibility complex class II, adhesion molecules, CD40 (a member of the TNFreceptor superfamily), prostaglandin, and heat shock protein expression in the orbit, thereby having a role in localizing and augmenting the inflammatory response (5). Locally released cytokines, particularly IL-1, TNF, and interferon , stimulate fibroblast proliferation and also activate fibroblasts to secrete the hydrophilic glycosaminoglycans (GAG) that cause edema with consequent proptosis. CD40 engagement leads to substantial increases in GAG synthesis in orbital fibroblasts. Also, CD40 ligand up-regulates the synthesis of IL-1 , and blocking this cytokine with exogenous IL-1 receptor antagonist or with IL-1 neutralizing antibodies partially attenuates the induction of prostaglandin endoperoxide H synthase-2. Thus, the CD40/CD40 ligand bridge represents a potentially important activational pathway for orbital fibroblasts that may underlie their cross-talk within the gateway of B-T-cell communication. Finally, smoking may be linked to GO through the generation of partial hypoxia, which increases GAG synthesis by fibroblasts, and by direct effects of cigarette smoke constituents on fibroblast activation (3). The disordered accumulation of the GAG in orbital and dermal connective tissues leads to the distinctive histological features associated with GD-related GO and dermopathy (6). This often occurs in the context of dramatic inflammation and tissue remodeling, which is a prominent feature of the extrathyroidal manifestations of GD and is apparently driven by activated T cells. GAG take part in extracellular matrix organization, the regulation of cell proliferation and differentiation, and the regulation of diffusion of macromolecules through tissues, growth factor attachment, cell-to-cell interaction, and regulation of IL-1 production in local inflammatory response. Hyaluronic acid (HA) is the largest GAG molecule containing several

Partial 7q11.23 deletions further implicate GTF2I and GTF2IRD1 as the main genes responsible for the Williams–Beuren syndrome neurocognitive profile

BackgroundWilliams–Beuren syndrome (WBS) is a developmental disorder with multisystemic manifestations mainly characterised by vascular stenoses, distinctive craniofacial features, mental retardation with a characteristic neurocognitive profile, and some endocrine and connective...

Arterial tortuosity syndrome in two Italian paediatric patients

BackgroundArterial tortuosity syndrome (ATS) (OMIM #208050) is a rare autosomal recessive connective tissue disorder characterized by tortuosity and elongation of the large and medium-sized arteries, propensity to aneurysms formation, vascular dissection, and pulmonary arteries stenosis. ATS is caused by mutations in SLC2A10 gene, encoding for the facilitative glucose transporter 10 (GLUT10). So far, 17 SLC2A10 mutations have been reported in 32 families, two of which were Italian with a total of five patients. Here we present the clinical and molecular characterization of two novel Italian paediatric ATS patients.MethodsThe exons and intronic flanking regions of SLC2A10 gene were amplified and direct sequencing was performed.ResultsIn both patients, the involvement of major- and medium-sized arteries was characteristic; the nonvascular connective tissue manifestations were mild and not pathognomic of the disorder. Both patients, born from non-consanguineous parents, were heterozygous for two different SLC2A10 mutations, three of which were recurrent and one was novel (p.Arg231Trp). This mutation is localized at the endofacial loop between the transmembrane domains 6 and 7 of GLUT10.ConclusionTwo novel ATS patients were characterized at clinical and molecular level. Overall, four ATS unrelated families are known in Italy so far. Though ATS clinical delineation improved in the last years, further works in the comprehension of disease presentation and complications onset, particularly in paediatric age, and on ATS molecular basis are needed to add new insights for diagnosis and prevention strategies for related complications.

Clinical manifestations, etiology, and pathogenesis of the hyper-IgE syndromes.

Autosomal dominant Hyper-IgE syndrome (AD-HIES) is a rare primary immunodeficiency characterized by eczema, recurrent skin and lung infections, elevated serum IgE, and various connective tissue, skeletal, and vascular abnormalities. Mutations in signal transducer and activator of transcription 3 (STAT3) have recently been found to account for most cases; however, the pathogenesis of the varied features remains poorly defined. A distinct syndrome, known as autosomal recessive HIES (AR-HIES) manifests as severe eczema, recurrent bacterial and viral skin infections, and sinopulmonary infections. As opposed to STAT3 deficient HIES, AR-HIES lacks the connective tissue and skeletal manifestations but has an increase in neurologic abnormalities. In this review, we discuss the clinical presentations, genetic etiologies, and immunologic abnormalities of these two syndromes. In addition, we discuss animal models of STAT3 deficiency that provide insight into the pathogenesis of HIES. Further understanding of how STAT3 results in the diverse manifestations of HIES will allow us to develop more specific therapies for HIES as well as for many of the manifestations, such as scoliosis, recurrent staphylococcal infections, and eczema, which are common in the general population.