Constitutional mosaicism in RASA1-related capillary malformation-arteriovenous malformation.

Capillary malformation-arteriovenous malformation (CM-AVM) is caused by germline RASA1 and EPHB4 alterations. RASA1 intralesional second hits have also been reported. Here we report RASA1 constitutional mosaicism, defined here as the presence of a mosaic variant in all cell types of an individual, in two patients with CM-AVM. High-throughput sequencing was used to search for RASA1 pathogenic variants in blood samples from two unrelated patients with CM-AVM. An affected tissue sample from one of the patients was also analyzed. Both patients showed different nonsense RASA1 variants in mosaic, ranging from 7% to 21.5%, in blood samples and in the corresponding affected tissue sample from one of the patients. In conclusion, we report for the first time the presence of RASA1 constitutional mosaicism in CM-AVM. Constitutional mosaicism has implications for accurate molecular diagnosis and recurrence risk and helps to explain the great phenotypic variability in CM-AVM.

CLAPO syndrome: identification of somatic activating PIK3CA mutations and delineation of the natural history and phenotype.

PURPOSE: CLAPO syndrome is a rare vascular disorder characterized by capillary malformation of the lower lip, lymphatic malformation predominant on the face and neck, asymmetry, and partial/generalized overgrowth. Here we tested the hypothesis that, although the genetic cause is not known, the tissue distribution of the clinical manifestations in CLAPO seems to follow a pattern of somatic mosaicism. METHODS: We clinically evaluated a cohort of 13 patients with CLAPO and screened 20 DNA blood/tissue samples from 9 patients using high-throughput, deep sequencing. RESULTS: We identified five activating mutations in the PIK3CA gene in affected tissues from 6 of the 9 patients studied; one of the variants (NM_006218.2:c.248T>C; p.Phe83Ser) has not been previously described in developmental disorders. CONCLUSION: We describe for the first time the presence of somatic activating PIK3CA mutations in patients with CLAPO. We also report an update of the phenotype and natural history of the syndrome.

Invasive lymphatic malformation (gorham-stout) of the pelvis with prominent skin involvement.

Gorham-Stout syndrome is a rare disease characterized by progressive osteolysis leading to disappearance of the bone. Vascular proliferations have been implicated in the pathogenesis of this syndrome. The case of a 7-year-old girl with a prominent invasive lymphatic malformation on the lumbosacral area and massive osteolysis of the pelvic girdle is reported.

Saltmarsh rhizosphere fungal communities vary by sediment type and dominant plant species cover in Nova Scotia, Canada.

We surveyed Spartina saltmarsh sediment rhizosphere fungal communities at three saltmarshes and two timepoints in coastal Nova Scotia. Based on ITS2 Illumina miSeq rDNA data and multivariate analysis, neither sediment zone nor collection period correlated with fungal ASV richness, but collection site did. However, Shannon diversity indicated that sediment zone played a significant role in fungal diversity. For unweighted and weighted UniFrac distance, site was the major factor driving beta-diversity, with sediment zone and collection period having smaller roles. Sediment type and saltmarsh plant species may play important roles in structuring rhizosphere fungal assemblages, here dominated by ascomycetes. To our knowledge, our study is the first to assess fungal sediment communities in saltmarshes in Atlantic Canada using metabarcoding. It provides a biodiversity analysis of sediment fungi in a poorly studied but highly important ecosystem and points to their roles in nutrient cycling, blue carbon, coastal stability and coastal restoration. Our work will inform ongoing saltmarsh restoration in Atlantic Canada.

Macrocephaly-capillary malformation: Analysis of 13 patients and review of the diagnostic criteria.

Macrocephaly-capillary malformation (M-CM) is a genetic syndrome of unknown etiology characterized by an enlarged head circumference and patchy, reticular capillary malformation. We describe the clinical features of 13 cases, report on the genome-wide Copy Number Variation characterization of these patients, analyze the main clinical features of this syndrome and propose a modification of the current diagnostic criteria: the inclusion of both overgrowth/asymmetry and neuroimaging alterations as major criteria.

Congenital hepatic hemangiomas: Clinical, histologic, and genetic correlation.

BACKGROUND: The guide for monitoring and treatment of congenital hepatic hemangiomas (CHH) will depend on the subtype and the postnatal clinical behavior. Our aim is to present a series of CHH and characterize its clinical, histologic and genetic correlation, compared to cutaneous congenital hemangiomas (CCH). MATERIAL AND METHODS: A retrospective review of CHH patients diagnosed between 1991 and 2018 was performed. Clinical, morphological and histological data were analyzed and deep high-throughput sequencing was performed. MAIN RESULTS: Sixteen patients with CHH were included. Five patients were followed up with serial ultrasounds while pharmacological treatment (corticosteroids and propranolol) was decided in five. Surgical resection was performed in five owing to hemorrhage and suspicion of malignancy, and the last patient underwent embolization. Histologic analysis was available in 7 patients and confirmed CHH, showing two different histological patterns that could be associated with the presence of somatic pathogenic variants in GNAQ and/or PIK3CA detected in the genetic testing. Review of 7 samples of CCH revealed some histologic differences compared to CHH. CONCLUSION: CHH resemble its cutaneous homonym with similar clinical behavior. Histologic analysis can differentiate two subgroups while genetic testing can confirm mutations in GNAQ and in PIK3CA in a subset of CHH. TYPE OF STUDY: Treatment study. LEVEL OF EVIDENCE: IV.

Vegetation and soil environment influence the spatial distribution of root-associated fungi in a mature beech-maple forest.

Although the level of diversity of root-associated fungi can be quite high, the effect of plant distribution and soil environment on root-associated fungal communities at fine spatial scales has received little attention. Here, we examine how soil environment and plant distribution affect the occurrence, diversity, and community structure of root-associated fungi at local patch scales within a mature forest. We used terminal restriction fragment length polymorphism and sequence analysis to detect 63 fungal species representing 28 different genera colonizing tree root tips. At least 32 species matched previously identified mycorrhizal fungi, with the remaining fungi including both saprotrophic and parasitic species. Root fungal communities were significantly different between June and September, suggesting a rapid temporal change in root fungal communities. Plant distribution affected root fungal communities, with some root fungi positively correlated with tree diameter and herbaceous-plant coverage. Some aspects of the soil environment were correlated with root fungal community structure, with the abundance of some root fungi positively correlated with soil pH and moisture content in June and with soil phosphorous (P) in September. Fungal distribution and community structure may be governed by plant-soil interactions at fine spatial scales within a mature forest. Soil P may play a role in structuring root fungal communities at certain times of the year.

Somatic activating mutations in PIK3CA cause generalized lymphatic anomaly.

Generalized lymphatic anomaly (GLA) is a vascular disorder characterized by diffuse or multifocal lymphatic malformations (LMs). The etiology of GLA is poorly understood. We identified four distinct somatic PIK3CA variants (Glu542Lys, Gln546Lys, His1047Arg, and His1047Leu) in tissue samples from five out of nine patients with GLA. These same PIK3CA variants occur in PIK3CA-related overgrowth spectrum and cause hyperactivation of the PI3K-AKT-mTOR pathway. We found that the mTOR inhibitor, rapamycin, prevented lymphatic hyperplasia and dysfunction in mice that expressed an active form of PIK3CA (His1047Arg) in their lymphatics. We also found that rapamycin reduced pain in patients with GLA. In conclusion, we report that somatic activating PIK3CA mutations can cause GLA, and we provide preclinical and clinical evidence to support the use of rapamycin for the treatment of this disabling and deadly disease.

Impact of maize mucilage on atrazine mineralization and atzC abundance.

Soil was amended with maize mucilage, a major rhizodeposit, to study its role on the number of culturable soil micro-organisms, the structure of the bacterial community, atrazine mineralization and atzC abundance. The maximal percentage of atrazine mineralization was lower for mucilage-amended than for water-amended soil. Total culturable soil bacteria and 16S rDNA copy number, measured by RT-PCR, presented similar values and were not significantly (P < 0.05) different among treatments. Mucilage applied at a rate of 70 microg C g(-1) dry soil day(-1) over two weeks did not modify the abundance of the total soil microflora. Global structure of soil bacterial communities revealed by RISA analysis was not modified by maize mucilage amendment. Abundance of atzC sequence was only augmented by mucilage addition at the beginning of the experiment. However, this increase was not sustainable in time, as atzC copy number increased in water-amended soil which, in turn, corresponded with the higher percentage of atrazine mineralization observed in this soil. Maize mucilage amendment alone contributed only to minor changes in the atrazine-degrading community in the studied soil.

Current Management of Vascular Tumors in the Neonate.

Neonatal vascular tumours present particular difficulties in their diagnosis and treatment. The special behaviour of neonatal hemangioma and the aggressive but benign nature of kaposiform hemangioendothelioma provide examples of a modern need for a conservative approach. Recent advances in their pharmacological management have dramatically changed the therapeutical scope of this group of tumors with surgery playing a minor role in their treatment. Multidisciplinary teams management involving neonatology, pediatric surgery, dermatology, pathology, genetics and radiology specialists among others remains the best option for an optimal outcome.

Quantification of denitrifying bacteria in soils by nirK gene targeted real-time PCR.

Denitrification, the reduction of nitrate to nitrous oxide or dinitrogen, is the major biological mechanism by which fixed nitrogen returns to the atmosphere from soil and water. Microorganisms capable of denitrification are widely distributed in the environment but little is known about their abundance since quantification is performed using fastidious and time-consuming MPN-based approaches. We used real-time PCR to quantify the denitrifying nitrite reductase gene (nirK), a key enzyme of the denitrifying pathway catalyzing the reduction of soluble nitrogen oxide to gaseous form. The real-time PCR assay was linear over 7 orders of magnitude and sensitive down to 10(2) copies by assay. Real-time PCR analysis of different soil samples showed nirK densities of 9.7x10(4) to 3.9x10(6) copies per gram of soil. Soil real-time PCR products were cloned and sequenced. Analysis of 56 clone sequences revealed that all cloned real-time PCR products exhibited high similarities to previously described nirK. However, phylogenetic analysis showed that most of environmental sequences are not related to nirK from cultivated denitrifiers.

Quantification of a novel group of nitrate-reducing bacteria in the environment by real-time PCR.

Nitrate reduction is performed by phylogenetically diverse bacteria. Analysis of narG (alpha subunit of the membrane bound nitrate reductase) trees constructed using environmental sequences revealed a new cluster that is not related to narG gene from known nitrate-reducing bacteria. In this study, primers targeting this as yet uncultivated nitrate-reducing group were designed and used to develop a real-time SYBR(R) Green PCR assay. The assay was tested with clones from distinct nitrate-reducing groups and applied to various environmental samples. narG copy number was high ranging between 5.08x10(8) and 1.12x10(11) copies per gram of dry weight of environmental sample. Environmental real-time PCR products were cloned and sequenced. Data was used to generate a phylogenetic tree showing that all environmental products belonged to the target group. Moreover, 16S rDNA copy number was quantified in the different environments by real-time PCR using universal primers for Eubacteria. 16S rDNA copy number was similar or slightly higher than that of narG, between 7.12x10(9) and 1.14x10(11) copies per gram of dry weight of environmental sample. Therefore, the yet uncultivated nitrate-reducing group targeted in this study seems to be numerically important in the environment, as revealed by narG high absolute and relative densities across various environments. Further analysis of the density of the nitrate-reducing community as a whole by real-time PCR may provide insights into the correlation between microbial density, diversity and activity.

Chylothorax and chylous ascites: management and pitfalls.

Leakage of lymph from the lymphatic ducts causes chylothorax (CT) or chylous ascitis (CA). This may happen for unknown reasons during fetal life or after birth and may also be caused by trauma after thoracic surgery or by other conditions. Fetal CT and CA may be lethal particularly in cases with fetal hydrops that sometimes benefit of intra-uterine instrumentation. After birth, symptoms are related to the amount of accumulated fluid. Sometimes, severe cardio-respiratory compromise prompts active therapy. Most patients with CT or CA benefit from observation, rest, and supportive measures alone. Drainage of the fluid may be necessary, but then loss of protein, fat, and lymphoid cells introduce new risks and require careful replacement. Low-fat diets with MCT and parenteral nutrition decrease fluid production while allowing adequate nutritional input. If lymph leakage does not stop, secretion inhibitors like somatostatin or octreotide are prescribed, although there is only weak evidence of their benefits. Imaging of the lymphatic system is indicated when the leaks persist, but this is technically demanding in children. Shunting of the lymph from one body space to another by means of valved catheters, embolization of the thoracic duct, and/or ligation of the major lymphatics may occasionally be indicated in cases refractory to all other treatments.

Osteolysis and lymphatic anomalies: a review of 54 consecutive cases.

BACKGROUND: Progressive osteolysis caused by lympathic malformations is a rare condition that should be known by specialists involved in the study of lymphatic disorders because they are necessarily involved in the treatment. The purpose of the present study is to report on a large series of patients to illustrate the multiple clinical pictures and the wide range of therapeutic measures necessary for arresting bone destruction and lymphatic leak. METHODS AND RESULTS: Inclusion criteria were osteolysis associated with lymphatic malformation that required treatment. Diagnosis was based on history, plain X-rays, MRI, and demonstration of the lymphatic nature of the lesions with D2-40 immunohistochemistry. Treatment was based on resection of the bone lytic lesion or soft tissue lymphatic masses, control of chylothorax or chyloperitoneum, interferon, zoledronic acid, and radiotherapy. The study included 54 patients (25 females and 29 males) with a median age of 9 years (range 2 to 65). Eight patients had focal osteolysis without soft tissue lymphatic anomaly, 15 multifocal osteolysis without soft tissue lymphatic anomaly, 7 focal osteolysis associated with soft tissue lymphatic anomaly, and 24 multifocal osteolysis with soft tissue lymphatic anomaly. Among the wide variety of pharmacological therapies provided, only one protocol showed a consistent positive effect (end of ostelytic progression) in 17 patients who received a course of 6 to 15 months of interferon alpha-2B at 1.5 million units/m(2) body surface area/day in association with zoledronic acid at 0.05 mg/kg/month. Thirty-two patients underwent multiple surgical procedures in order to remove the soft tissue involved, correct orthopedic problems, or improve chylothorax, and three were treated with radiotherapy which was successful in one case. CONCLUSIONS: Osteolysis from lymphatic origin is a devastating surgical condition. Therapeutic options have to be considered separately if the disease is active or inactive and according to the targeted organ (skin, bone, or viscera). Total removal of the lymphatic anomaly is rarely possible, but its subtotal excision together with pharmacological antiangiogenic therapy in selected patients under surveillance of a multidisciplinary group familiarized with the disease, minimize the progression of both, lymphatic invasion, osteolysis, and their serious complications.

Major and minor arterial malformations in patients with cutaneous vascular abnormalities.

The association of persistent embryonic arteries and the absence of 1 carotid or vertebral arteries with facial or neck hemangioma or vascular malformation have been frequently described. The abnormalities can involve major or minor vessels. Of 22 patients of our series with this neurocutaneous syndrome, 20 had the origin of both anterior cerebral arteries from the same internal carotid artery. Thirteen patients showed absence or hypoplasia of 1 carotid artery and 10 of 1 vertebral artery; 10 showed persistence of the trigeminal artery; 3 had persistent proatlantal artery; 6 showed the absence of the posterior communicating artery; and 4 had hypoplastic posterior cerebral artery. Other less frequent abnormalities were found in 7 patients. Intellectual level of most patients was either borderline or below normal. Abnormalities in the vascularization and perfusion of the frontal lobes may contribute to the borderline or lower mental level of these patients.

The role of GLUT1 immunostaining in the diagnosis and classification of liver vascular tumors in children.

BACKGROUND/AIM: GLUT1 is an erythrocyte-type glucose transporter protein typically expressed in cutaneous proliferating hemangioma. Immunostaining for GLUT1 is becoming valuable for predicting the outcome of vascular skin tumors. Liver vascular tumors (LVTs) are a serious challenge for pediatric surgeons because of their often severe and sometimes unpredictable clinical course. To improve therapeutic strategies, we designed this study in which we tested in pathology specimens of LVT the hypothesis that GLUT1 expression could be useful to understand and classify LVT. MATERIAL AND METHODS: In the last 10 years, we treated 20 children with LVT. Pathology specimens from biopsy, excision, or autopsy were available in 11 of them. The paraffin sections were immunostained for GLUT1 and also for Ki-67 to assess the proportion of proliferating cells. Patients were divided into 2 groups: GLUT1-positive (n = 4) and GLUT1-negative (n = 7) that were compared for age at diagnosis, survival, and proportion of proliferating cells. Nonparametric and chi 2 tests were used for statistical analysis as appropriate. RESULTS: Mean age at diagnosis was higher in GLUT1-positive group, although not statistically significant in comparison with GLUT1-negative (308 +/- 515 vs 70 +/- 51 days, respectively). Three of 4 children in GLUT1-positive group died versus 1 of 7 in the GLUT1-negative group (not significant). All GLUT1-positive tumors were multicentric hemangiomata without central necrosis and only 1 with large vessels. Among GLUT1-negative tumors, 5 were solitary masses and 2 were multicentric (the value of the last 2 specimens was uncertain), 2 had central necrosis, and 2 had large vessels. Proliferation index was 18% +/- 1.42% and 1.42% +/- 0.97%, respectively, in each group ( P < .05). CONCLUSIONS: GLUT1-positive tumors have significantly higher proliferation rates than negative ones. Mortality tended to be higher in children with GLUT1-positive tumors. Positive GLUT1 immunostaining is likely specific for proliferating hemangioma, and it predicts the typical course of proliferation followed by involution.