Publications by authors named "Laurence Boon"

Article Synopsis
  • * Most of these malformations occur sporadically, but some may be inherited, often linked to mutations that activate pathways similar to those found in cancer.
  • * The review discusses new advancements in precision medicine that utilize targeted molecular inhibitors and repurposed cancer drugs to create more effective treatments for both slow-flow and fast-flow vascular malformations.
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  • PIK3CA gene variants are linked to vascular malformations, and this study aimed to analyze their phenotypes, locations within the gene, and frequency in patients with these conditions.
  • Data was collected from 558 patients with vascular malformations between 2008 and 2022, with genetic testing performed on biopsy samples starting in 2020, leading to 89 patients being included by June 2022.
  • The research found 25 PIK3CA variants, predominantly in nonsyndromic (simple/combined) vascular malformations, with notable hotspot and non-hotspot variants and significant differences in variant frequency between syndromic and nonsyndromic cases, highlighting the genetic diversity underlying these conditions.
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  • Blue rubber bleb nevus syndrome (BRBNS) is a rare congenital condition affecting blood vessels, often leading to lesions in the skin, tissues, and various organs, with limited knowledge on its orthopedic complications!* -
  • A case study highlights a patient with BRBNS who experienced severe venous malformation in the hip that caused bone deformities, impacts on muscular development, and significant hip joint issues, leading to the need for total hip arthroplasty at age 18!* -
  • The case illustrates how vascular malformations can cause hip dysplasia and joint instability, emphasizing the importance of tailored surgical planning for optimal outcomes in patients with BRBNS.*
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Vascular malformations, which arise from anomalies in angiogenesis, encompass capillary, lymphatic, venous, arteriovenous, and mixed malformations, each affecting specific vessel types. Historically, therapeutic options such as sclerotherapy and surgery have shown limited efficacy in complicated malformations. Most vascular malformations stem from hereditary or somatic mutations akin to oncogenic alterations, activating the PI3K-AKT-mTOR, RAS-MAPK-ERK, and G-protein coupled receptor pathways.

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Primary lymphedema (PL), characterized by tissue swelling, fat accumulation, and fibrosis, results from defects in lymphatic vessels or valves caused by mutations in genes involved in development, maturation, and function of the lymphatic vascular system. Pathogenic variants in various genes have been identified in about 30% of PL cases. By screening of a cohort of 755 individuals with PL, we identified two TIE1 (tyrosine kinase with immunoglobulin- and epidermal growth factor-like domains 1) missense variants and one truncating variant, all predicted to be pathogenic by bioinformatic algorithms.

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Repurposing anticancer drugs to vascular malformations has significantly improved patient outcomes. Complex Lymphatic Anomalies (CLA) are part of the spectrum of lymphatic malformations (LMs) that share similar oncogenic mutations to cancer. We report the case of a young patient with highly symptomatic CLA who was initially treated with sirolimus, due to the frequent involvement of the PI3K-AKT-mTOR pathway in CLA pathogenesis.

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Background: To assess the impact of propranolol as the first-line treatment of infantile hemangioma (IH) on the need for surgery in the management of IH.

Methods: Retrospective study of 420 patients, with IH, referred to our multidisciplinary center between January 2005 and August 2014. Clinical data including sex, age at first consultation and at treatment initiation, location, size, number, aspect, and complication of IH, as well as the type of treatment were collected.

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Background: Venous malformations (VMs) are commonly associated with localized intravascular coagulopathy leading to elevated D-dimer and risks of hemorrhagic and thromboembolic events, particularly in extensive lesions. While low-molecular-weight heparin (LMWH) has been effective in managing coagulopathy and pain, direct oral anticoagulants (DOACs) emerge as a promising alternative.

Objectives: This study aims to evaluate the efficacy and safety of DOACs in treating VMs associated with localized intravascular coagulopathy, offering a comparative perspective to LMWH.

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Developmental and functional defects in the lymphatic system are responsible for primary lymphoedema (PL). PL is a chronic debilitating disease caused by increased accumulation of interstitial fluid, predisposing to inflammation, infections and fibrosis. There is no cure, only symptomatic treatment is available.

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Article Synopsis
  • Common capillary malformations typically involve mutations in GNAQ or GNA11, but this study found other genetic causes by analyzing 82 lesions for mutations in PIK3R1 and PIK3CA.
  • The researchers identified 9 somatic pathogenic variants that led to a specific phenotype, characterized by pale capillary malformations with visible dilated veins and abnormal signaling pathways related to disease development.
  • Using zebrafish embryos, they demonstrated that these mutations affect vascular development, and highlighted that the elevated Akt signaling caused by the mutations can be countered by specific inhibitors, paving the way for potential targeted treatments.
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Capillary malformations (CMs) are the most common type of vascular anomalies, affecting around 0.3% of newborns. They are usually caused by somatic pathogenic variants in GNAQ or GNA11.

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Article Synopsis
  • Slow-flow vascular malformations often have mutations in the PI3K/AKT/mTOR pathway, prompting the need for effective drug therapies like sirolimus, which has shown promise in prior trials.
  • The VASE trial is a large-scale, ongoing phase III study initiated in 2016, assessing the efficacy and safety of sirolimus over 2 years in both pediatric and adult patients with these conditions.
  • Preliminary results show that 85% of patients experienced clinical improvement, with some adverse effects reported; however, many patients experienced a recurrence of symptoms after treatment ended.
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Unlabelled: To elaborate expert consensus patient pathways to guide patients and physicians toward efficient diagnostics and management of patients with venous malformations.

Methods: VASCERN-VASCA (https://vascern.eu/) is a European network of multidisciplinary centers for Vascular Anomalies.

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Sirolimus, by targeting the mammalian target of rapamycin (mTOR) pathway, has demonstrated efficacy on lymphatic malformations (LMs) in adults and neonates. The current hypothesis is that the earlier the lesion is treated, the better it responds. This has prompted the idea that sirolimus administration might be efficacious to treat fetal LMs as well.

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Background: Primary lymphoedema (PL) is a chronic, debilitating disease caused by developmental and functional defects of the lymphatic system. It is marked by an accumulation of interstitial fluid, fat and tissue fibrosis. There is no cure.

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Objective: In recent years, genotypic characterization of congenital vascular malformations (CVMs) has gained attention; however, the spectrum of clinical phenotype remains difficult to attribute to a genetic cause and is rarely described in the adult population. The aim of this study is to describe a consecutive series of adolescent and adult patients in a tertiary center, where a multimodal phenotypic approach was used for diagnosis.

Methods: We analyzed clinical findings, imaging, and laboratory results at initial presentation, and set a diagnosis according to the International Society for the Study of Vascular Anomalies (ISSVA) classification for all consecutively registered patients older than 14 years of age who were referred to the Center for Vascular Malformations at the University Hospital of Bern between 2008 and 2021.

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Gorham Stout disease is a very rare monostotic or polyostotic osteolysis and physiopathology of the osteolysis is not yet fully understood. Three new cases are reported with their evolution and treatment. Among these 3 cases, two are very rare cases of polyostotic involvement.

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Lymphatic malformations (LMs) are developmental defects of lymphatic vessels. LMs are histologically benign lesions, however, due to localization, size, and unexpected swelling, they may cause serious complications that threaten vital functions such as compression of the airways. A large swelling of the face or neck may also be disfiguring and thus constitute a psychological strain for patients and their families.

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Somatic activating Kirsten rat sarcoma viral oncogene homologue (KRAS) mutations have been reported in patients with arteriovenous malformations. By producing LSL-Kras (G12D); Cdh5 (PAC)-CreERT2 [iEC-Kras (G12D*)] mice, we hoped to activate KRAS within vascular endothelial cells (ECs) to generate an arteriovenous malformation mouse model. Neonatal mice were treated daily with tamoxifen from postnatal (PN) days 1-3.

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Background And Purpose: Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by clinical manifestations involving the brain, eye and skin. SWS is commonly caused by somatic mutations in G protein subunit Alpha Q (GNAQ). Five cases of subunit Alpha 11 (GNA11) mutations have been reported.

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Arteriovenous malformations (AVMs) are fast-flow lesions that may be destructive and are the most difficult-to-treat vascular anomalies. Embolization followed by surgical resection is commonly used; however, complete resection is rarely possible and partial resection often leads to dramatic worsening. Accumulating data implicate abnormal angiogenic activity in the development of AVMs.

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Vascular anomalies are a heterogenous group of vascular lesions that can be divided, according to the International Society for the Study of Vascular Anomalies Classification, into two main groups: vascular tumors and vascular malformations. Vascular malformations can be further subdivided into slow-flow and fast-flow malformations. This clinical and radiological classification allows for a better understanding of vascular anomalies and aims to offer a more precise final diagnosis.

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The European Reference Network on Rare Multisystemic Vascular Diseases (VASCERN), is dedicated to gathering the best expertise in Europe and provide accessible cross-border healthcare to patients with rare vascular diseases. Infantile Hemangiomas (IH) are benign vascular tumors of infancy that rapidly growth in the first weeks of life, followed by stabilization and spontaneous regression. In rare cases the extent, the localization or the number of lesions may cause severe complications that need specific and careful management.

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Central conducting lymphatic anomaly (CCLA), characterized by the dysfunction of core collecting lymphatic vessels including the thoracic duct and cisterna chyli, and presenting as chylothorax, pleural effusions, chylous ascites, and lymphedema, is a severe disorder often resulting in fetal or perinatal demise. Although pathogenic variants in RAS/mitogen activated protein kinase (MAPK) signaling pathway components have been documented in some patients with CCLA, the genetic etiology of the disorder remains uncharacterized in most cases. Here, we identified biallelic pathogenic variants in , encoding the MyoD family inhibitor domain containing protein, in seven individuals with CCLA from six independent families.

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