Bi-allelic Variations of SMO in Humans Cause a Broad Spectrum of Developmental Anomalies Due to Abnormal Hedgehog Signaling.

The evolutionarily conserved hedgehog (Hh) pathway is essential for organogenesis and plays critical roles in postnatal tissue maintenance and renewal. A unique feature of the vertebrate Hh pathway is that signal transduction requires the primary cilium (PC) where major pathway components are dynamically enriched. These factors include smoothened (SMO) and patched, which constitute the core reception system for sonic hedgehog (SHH) as well as GLI transcription factors, the key mediators of the pathway. Here, we report bi-allelic loss-of-function variations in SMO in seven individuals from five independent families; these variations cause a wide phenotypic spectrum of developmental anomalies affecting the brain (hypothalamic hamartoma and microcephaly), heart (atrioventricular septal defect), skeleton (postaxial polydactyly, narrow chest, and shortening of long bones), and enteric nervous system (aganglionosis). Cells derived from affected individuals showed normal ciliogenesis but severely altered Hh-signal transduction as a result of either altered PC trafficking or abnormal activation of the pathway downstream of SMO. In addition, Hh-independent GLI2 accumulation at the PC tip in cells from the affected individuals suggests a potential function of SMO in regulating basal ciliary trafficking of GLI2 when the pathway is off. Thus, loss of SMO function results in abnormal PC dynamics of key components of the Hh signaling pathway and leads to a large continuum of malformations in humans.

Pediatric Tumors and Developmental Anomalies: A French Nationwide Cohort Study.

OBJECTIVE: To assess the associations between congenital abnormalities and pediatric malignancies and evaluate the potential underlying molecular basis by collecting information on pediatric patients with cancer and congenital abnormalities. STUDY DESIGN: Tumeur Et Développement is a national, prospective, and retrospective multicenter study recording data of children with cancer and congenital abnormalities. When feasible, blood and tumoral samples are collected for virtual biobanking. RESULTS: From June 2013 to December 2019, 679 associations between pediatric cancers and congenital abnormalities were recorded. The most represented cancers were central nervous system tumors (n = 139; 20%), leukemia and myelodysplastic syndromes (n = 123; 18.1%), and renal tumors (n = 101; 15%). Congenital abnormalities were not related to any known genetic disorder in 66.5% of cases. In this group, the most common anomaly was intellectual disability (22.3%), followed by musculoskeletal (14.2%) and genitourinary anomalies (12.4%). Intellectual disability was mostly associated with hematologic malignancies. Embryonic tumors (neuroblastoma, Wilms tumor, and rhabdomyosarcoma) were associated with consistent abnormalities, sometimes with a close anatomical neighborhood between the abnormality and the neoplasm. CONCLUSIONS: In the first Tumeur Et Développement analysis, 3 major themes have been identified: (1) germline mutations with or without known cancer predisposition, (2) postzygotic events responsible for genomic mosaicism, (3) coincidental associations. New pathways involved in cancer development need to be investigated to improve our understanding of childhood cancers.

Detection and localization of calcium oxalate in kidney using synchrotron deep ultraviolet fluorescence microscopy.

Renal oxalosis is a rare cause of renal failure whose diagnosis can be challenging. Synchrotron deep ultraviolet (UV) fluorescence was assayed to improve oxalosis detection on kidney biopsies spatial resolution and sensitivity compared with the Fourier transform infrared microspectroscopy gold standard. The fluorescence spectrum of synthetic mono-, di- and tri-hydrated calcium oxalate was investigated using a microspectrometer coupled to the synchrotron UV beamline DISCO, Synchrotron SOLEIL, France. The obtained spectra were used to detect oxalocalcic crystals in a case control study of 42 human kidney biopsies including 19 renal oxalosis due to primary (PHO, n = 11) and secondary hyperoxaluria (SHO, n = 8), seven samples from PHO patients who received combined kidney and liver transplants, and 16 controls. For all oxalocalcic hydrates samples, a fluorescence signal is detected at 420 nm. These spectra were used to identify standard oxalocalcic crystals in patients with PHO or SHO. They also revealed micrometric crystallites as well as non-aggregated oxalate accumulation in tubular cells. A nine-points histological score was established for the diagnosis of renal oxalosis with 100% specificity (76-100) and a 73% sensitivity (43-90). Oxalate tubular accumulation and higher histological score were correlated to lower estimated glomerular filtration rate and higher urinary oxalate over creatinine ratio.

Clinical, pathologic, and molecular features of inflammatory myofibroblastic tumors in children and adolescents.

BACKGROUND: Inflammatory myofibroblastic tumors (IMT) are rare, intermediate malignant tumors harboring frequent somatic molecular rearrangements. The management of IMT has not been standardized. METHODS: A retrospective multicenter study was conducted on all pediatric patients treated for IMT between 2000 and 2019. RESULTS: This series included 39 cases of IMT, with a median age at diagnosis of 7 years (range 20 days to 16 years). Tumor location included pelvis-abdomen (n = 16), thorax (n = 14), head and neck (n = 7), and limbs (n = 2). One patient had metastatic disease. Immunochemistry showed 21/39 (54%) anaplastic lymphoma kinase (ALK)-positive tumors. Somatic tyrosine kinase rearrangement was present in 31/36 (86%) of the tumors analyzed: 21 ALK, five ROS1, and five NTRK. Immediate surgery was performed in 24 patients (62%), with adjuvant therapy for three patients. Delayed surgery after neoadjuvant therapy was possible in 10 cases. Exclusive systemic therapy was delivered to four patients; one patient with orbital IMT was managed by watchful waiting. After a median follow-up of 33 months (range 5-124), eight (20%) recurrences/progressions occurred after surgery (seven after primary surgery and one after delayed surgery), after a median interval of 7 months (range 2-21), all in thoracic locations. The 3-year overall and disease-free survivals were 96.8% (95% CI: 79.2%-94.0%) and 77.4% (95% CI: 59.6%-88.1%), respectively. Relapses/progressions were more common in patients with a thoracic primary (p < .001) or after incomplete surgery with no adjuvant therapy (p = .027). CONCLUSION: Surgery is effective in most cases of pediatric IMT. Systematic analysis of tyrosine kinase rearrangement is recommended. When the tumor is deemed only partially resectable to preserve organs and function, neoadjuvant therapy may be proposed to allow adequate conservative surgery.

Lessons from a large nationwide cohort of 350 children with ovarian mature teratoma: A study in favor of ovarian-sparing surgery.

BACKGROUND: Ovarian mature teratoma (OMT) is a common ovarian tumor found in the pediatric population. In 10%-20% of cases, OMT occurs as multiple synchronous or metachronous lesions on ipsi- or contralateral ovaries. Ovarian-sparing surgery (OSS) is recommended to preserve fertility, but total oophorectomy (TO) is still performed. DESIGN: This study reviews the clinical data of patients with OMT, and analyzes risk factors for second events. A national retrospective review of girls under 18 years of age with OMTs was performed. Data on clinical features, imaging, laboratory studies, surgical reports, second events and their management were retrieved. RESULTS: Overall, 350 children were included. Eighteen patients (5%) presented with a synchronous bilateral form at diagnosis. Surgery was performed by laparotomy (85%) and laparoscopy (15%). OSS and TO were performed in 59% and 41% of cases, respectively. Perioperative tumor rupture occurred in 23 cases, independently of the surgical approach. Twenty-nine second events occurred (8.3%) in a median time of 30.5 months from diagnosis (ipsilateral: eight cases including one malignant tumor; contralateral: 18 cases; both ovaries: three cases). A large palpable mass, bilateral forms, at diagnosis and perioperative rupture had a statistical impact on the risk of second event, whereas the type of surgery or approach did not. CONCLUSION: This study is a plea in favor of OSS as the first-choice treatment of OMT when possible. Close follow-up during the first 5 years is mandatory considering the risk of 8.3% of second events, especially in cases with risk factors.

A kidney discard decision strategy based on zero-time histology analysis could lead to an unjustified increase in the organ turndown rate among ECD.

The utility of zero-time kidney biopsies (KB) in deciding to accept expanded criteria donor (ECD) kidneys remains controversial. However, zero-time histology is one of the main causes for discarding kidneys in the United States. In a single-centre study, we examined the utility and impact on outcome of the use of frozen section zero-time KB among ECD. Ninety-two zero-time KB were analysed for accept/discard decision between 2005 and 2015 among ECD. 53% of kidneys were rejected after zero-time KB analysis; there was no difference in individual clinical and biological data between accepted/rejected groups. However, histology of rejected kidneys showed more sclerotic glomeruli (20% vs. 8%; P < 0.001), increased interstitial fibrosis (1.25 ± 0.12 vs. 0.47 ± 0.09; P < 0.0001), more arteriosclerosis (2.14 ± 0.17 vs. 1.71 ± 0.11; P = 0.0032) and arteriolar hyalinosis (2.15 ± 0.12 vs. 1.55 ± 0.11; P = 0.0006). Using propensity score matching, we generated a group of 42 kidney allograft recipients who received a transplant matched for donor zero-time histology and clinical characteristics with donors whose kidneys were rejected. Interestingly, their 1- and 5-year graft survival and function were similar to the global cohort of ECD recipients. In conclusion, when performed, zero-time KB was a decisive element for kidney discard decision. However, adverse zero-time histology was not associated with poorer graft survival and kidney function among ECD.

Beyond 10 years, with or without an intestinal graft: Present and future?

Long-term outcomes in children undergoing intestinal transplantation remain unclear. Seventy-one children underwent intestinal transplantation in our center from 1989 to 2007. We report on 10-year posttransplant outcomes with (group 1, n = 26) and without (group 2, n = 9) a functional graft. Ten-year patient and graft survival rates were 53% and 36%, respectively. Most patients were studying or working, one third having psychiatric disorders. All patients in group 1 were weaned off parenteral nutrition with mostly normal physical growth and subnormal energy absorption. Graft histology from 15 late biopsies showed minimal abnormality. However, micronutrient deficiencies and fat malabsorption were frequent; biliary complications occurred in 4 patients among the 17 who underwent liver transplantation; median renal clearance was 87 mL/min/1.73 m2 . Four patients in group 1 experienced late acute rejection. Among the 9 patients in group 2, 4 died after 10 years and 2 developed significant liver fibrosis. Liver transplantation and the use of a 3-drug regimen including sirolimus or mycophenolate mofetil were associated with improved graft survival. Therefore, intestinal transplantation may enable a satisfactory digestive function in the long term. The prognosis of graft removal without retransplantation is better than expected. Regular monitoring of micronutrients, early psychological assessment, and use of sirolimus are recommended.

Pure pediatric ovarian immature teratomas: The French experience.

OBJECTIVE: To describe characteristics and outcome of pediatric ovarian immature teratomas (IT) to better define the place of chemotherapy. METHODS: Children with ovarian IT enrolled in TGM95 and TGM2013 studies were analyzed. Norris grading and International Federation of Gynecology and Obstetrics staging system were used. RESULTS: Thirty-six cases were identified with a median age of 11 years (range = 1-18): 35 of 36 stage I (17 stage IA, 13 stage IC, and 5 stage IX), including seven patients with gliomatosis peritonei (GP), and 1 stage IIIB (IT peritoneal implants). Centrally reviewed Norris grading was performed in 31 cases: 14 grade I and 17 grade II/III tumors. All patients underwent upfront surgery: 19 unilateral oophorectomy, 14 unilateral adnexectomy, 2 unilateral cystectomy, and 1 bilateral cystectomy. No extensive GP surgery was performed. Six patients received adjuvant vinblastin, bleomycin, and cisplatinum because of tumor rupture (n = 5, including two patients with GP) or stage III (n = 1). After a median follow-up of 39.5 months (range = 6-238), two events occurred 10 and 11 months after diagnosis: one bilateralization (initial stage IX, grade I) and one IT peritoneal relapse (initial stage IA, grade II), respectively. Both were successfully rescued by platinum-based chemotherapy and delayed surgery. No stage IC patients treated without adjuvant chemotherapy relapsed (four grade I and three grade III). None of the seven patients with GP progressed. Five-year event-free survival and overall survival were 94% (95% CI = 81-98%) and 100%. CONCLUSIONS: The current series confirms the excellent prognosis of pediatric ovarian IT, arguing for conservative surgical approach in GP and against systematic adjuvant chemotherapy, even in ruptured tumors.

Cherubism as a systemic skeletal disease: evidence from an aggressive case.

BACKGROUND: Cherubism is a rare autosomal dominant genetic condition caused by mutations in the SH3BP2 gene. This disease is characterized by osteolysis of the jaws, with the bone replaced by soft tissue rich in fibroblasts and multinuclear giant cells. SH3BP2 is a ubiquitous adaptor protein yet the consequences of SH3BP2 mutation have so far been described as impacting only face. Cherubism mouse models have been generated and unlike human patients, the knock-in mice exhibit systemic bone loss together with a systemic inflammation. CASE PRESENTATION: In light of these observations, we decided to search for a systemic cherubism phenotype in a 6-year-old girl with an aggressive cherubism. We report here the first case of cherubism with systemic manifestations. Bone densitometry showed low overall bone density (total body Z-score = - 4.6 SD). Several markers of bone remodelling (CTx, BALP, P1NP) as well as inflammation (TNFα and IL-1) were elevated. A causative second-site mutation in other genes known to influence bone density was ruled out by sequencing a panel of such genes. CONCLUSIONS: If this systemic skeletal cherubism phenotype should be confirmed, it would simplify the treatment of severe cherubism patients and allay reservations about applying a systemic treatment such as those recently published (tacrolimus or imatinib) to a disease heretofore believed to be localised to the jaws.

Pulmonary hypertension after bone marrow transplantation in children.

INTRODUCTION: Pulmonary hypertension is a rare but important cause of mortality after haematopoietic stem cell transplantation (HSCT) in children. This complication is poorly characterised in the literature. We report here a series of children who developed pulmonary hypertension after HSCT. METHODS: Between January 2008 and December 2015, we retrospectively analysed 366 children who underwent HSCT (age range 0.5-252 months; median 20.3 months). During the post-HSCT course, echocardiography scans motivated by respiratory symptoms identified 31 patients with elevated tricuspid regurgitation velocity (>2.8 m·s-1), confirmed when possible by right heart catheterisation (RHC). RESULTS: 22 patients had confirmed pulmonary hypertension with mean±sd pulmonary arterial pressure 40.1±10 mmHg (range 28-62 mmHg) and pulmonary vascular resistance 17.3±9.2 Wood Units (range 8-42 Wood Units). Among the 13 responders at reactivity test, only one patient responded to calcium channel blockers. Seven patients (32%) died. 15 pulmonary hypertension patients were alive after a mean±sd follow-up of 6.5±2.3 years (range 2-10 years). All survivors could be weaned off pulmonary hypertension treatment after a median follow-up of 5 months (range 3-16). The delay between clinical symptoms and initiation of pulmonary hypertension therapy was significantly longer in patients who subsequently died (mean±sd 33.5±23 days; median 30 days) than in survivors (mean±sd 7±3 days) (p<0.001). CONCLUSION: Pulmonary hypertension is a severe complication of HSCT with an underestimated incidence and high mortality. Aggressive and timely up-front combination therapy allowed normalisation of pulmonary pressure and improved survival.

Revisiting the role of the pathological grading in pediatric adrenal cortical tumors: results from a national cohort study with pathological review.

The prognosis of malignant pediatric adrenocortical tumors is closely related to disease stage, which is used to guide perioperative treatment recommendations. However, current scoring systems are inadequate to distinguish between benign and malignant adrenocortical tumors. Robust microscopic prognostic features that could help determine perioperative therapy are also lacking. The aim of this national study was to review the prognostic value of the Wieneke scoring criteria and Ki67 labeling index in unselected pediatric adrenocortical tumors. Using strict definitions previously defined by expert pathologists, a Wieneke score was re-attributed to each tumor after an independent and centralized review. In addition, Ki67 proliferation index was performed and reviewed for each case. A total of 95 cases were selected; all were treated between 2000 and 2018 and had histopathologic material and sufficient outcome-related information available. Localized disease was found in 88% of patients. Among those with advanced disease, 6% had tumor extension into adjacent organs and 5% had metastases at diagnosis. Median follow-up was 5 years and 3 months. The 5-year PFS was 82%, 95% CI [73%-91%]. Tumor stage significantly correlated with PFS (p < 0.0001). Tumor weight up to 200 g, extra-adrenal extension and initial non-complete surgical resection were statistically associated with worse outcomes. No recurrences nor metastases occurred when the Ki67 index was < 15%. Up to two of the following five factors including tumor necrosis, adrenal capsular invasion, venous invasion, mitotic count > 15/20 high-power fields, and Ki67 index > 15%, significantly correlated with worse outcomes. We propose a pathological scoring system incorporating the Ki67 index as part of a two-step approach after disease staging to guide adjuvant treatment in pediatric adrenocortical tumors, especially after incomplete resection. These results should be validated in an independent cohort.

Fulminant arterial vasculitis as an unusual complication of disseminated staphylococcal disease due to the emerging CC1 methicillin-susceptible Staphylococcus aureus clone: a case report.

BACKGROUND: Staphylococcus aureus has emerged as a leading cause of invasive severe diseases with a high rate of morbidity and mortality worldwide. The wide spectrum of clinical manifestations and outcome observed in staphylococcal illness may be a consequence of both microbial factors and variability of the host immune response. CASE PRESENTATION: A 14-years old child developed limb ischemia with gangrene following S. aureus bloodstream infection. Histopathology revealed medium-sized arterial vasculitis. The causing strain belonged to the emerging clone CC1-MSSA and numerous pathogenesis-related genes were identified. Patient's genotyping revealed functional variants associated with severe infections. A combination of virulence and host factors might explain this unique severe form of staphylococcal disease. CONCLUSION: A combination of virulence and genetic host factors might explain this unique severe form of staphylococcal disease.

Prenatal Diagnosis of a Melanotic Neuroectodermal Tumor of Infancy (MNTI): A Case Report With a Favorable Outcome After Chemotherapy Failure and Incomplete Resection.

We present the case of a woman referred to our department at 34 weeks of pregnancy with a fetal ultrasonographic scan showing a mass that had developed within the right maxilla with invasion of the orbit. A retrospective examination showed that this tumor had been present since the 12th week of pregnancy. At 39+4 weeks of gestation, a boy was born. He presented a black firm aspect in the maxilla. A computed tomographic scan and magnetic resonance imaging revealed a soft tissue swelling over the right maxilla, extending into the orbit but without invasion of the globe. Surgical biopsy confirmed a melanotic neuroectodermal tumor of infancy. The pathologic examination did not show any neuroblast-like component on the hematoxylin eosin saffron staining. Because of the extension and the size of the lesion, neoadjuvant chemotherapy was carried out. At day 21, the patient received 1 cycle of low-dose cyclophosphamide and vincristine, 2 cycles of etoposide and carboplatin, and thereafter 1 cycle of cyclophosphamide, adriamycin, and vincristin because the lesion kept growing. After stabilization of the size of the tumor, at 4 months, a maxillectomy and partial resection of the orbital floor and lateral orbital wall was performed on the patient. As a complete resection would have required orbital exenteration, surgery was performed deliberately incomplete leaving a macroscopic residue (R2). At 2.5 years of follow-up, the patient showed complete remission with no lesions evident on magnetic resonance imaging.

No correlation between mtDNA amount and methylation levels at the CpG island of POLG exon 2 in wild-type and mutant human differentiated cells.

BACKGROUND: While mitochondrial DNA (mtDNA) copy number is strictly regulated during differentiation and according to cell type, very little is known regarding the mechanism which accurately controls mtDNA copy number in human. Exon 2 of the human POLG gene, encoding the catalytic subunit of the mitochondrial-specific DNA polymerase gamma, contains a CpG island, highly conserved in mice and human. Changes of DNA methylation at the POLG locus have been shown to modulate mtDNA copy number during cell differentiation in both mouse and human. METHODS: We have investigated the epigenetic modification of the POLG gene, by assessing the methylation level of its exon 2 using deep-Next Generation Sequencing analysis of bisulfite-treated DNA. Analysis were performed on various tissues at either postnatal or prenatal stages, on samples from carriers of mtDNA mutations, patients carrying two loss-of-function POLG mutations and controls. RESULTS: Very high methylation levels at POLG exon 2 were found (94±3%) and no variation was observed according to either developmental stage or tissue of origin, except for sperm samples for which lower methylation levels were found (80%). This high level of methylation was neither correlated with the presence of mtDNA mutations (94±1% of methylated alleles), nor with biallelic POLG mutations (93%±2%), even in tissues where a mtDNA depletion had been observed. CONCLUSIONS: This study suggests that, at variance with mouse and un/de-differentiated human cells, differentiated human cells control mtDNA levels irrespective of POLG methylation. The factors which actually control the mtDNA levels in such cell types remain to be identified.

Molecular analyses of juvenile granulosa cell tumors bearing AKT1 mutations provide insights into tumor biology and therapeutic leads.

Juvenile granulosa cell tumors (JGCTs) of the ovary are pediatric neoplasms representing 5% of all granulosa cell tumors (GCTs). Most GCTs are of adult type (AGCTs) and bear a mutation in the FOXL2 gene. The molecular basis of JGCTs is poorly understood, although mutations in the GNAS gene have been reported. We have detected in-frame duplications within the oncogene AKT1 in >60% of the JGCTs studied. Here, to evaluate the functional impact of these duplications and the existence of potential co-driver alterations, we have sequenced the transcriptome of four JGCTs and compared them with control transcriptomes. A search for gene variants detected only private alterations probably unrelated with tumorigenesis, suggesting that tandem duplications are the best candidates to underlie tumor formation in the absence of GNAS alterations. We previously showed that the duplications were specific to JGCTs. However, the screening of eight AGCTs samples without FOXL2 mutation showed the existence of an AKT1 duplication in one case, also having a stromal luteoma. The analysis of RNA-Seq data pinpointed a series of differentially expressed genes, involved in cytokine and hormone signaling and cell division-related processes. Further analyses pointed to the existence of a possible dedifferentiation process and suggested that most of the transcriptomic dysregulation might be mediated by a limited set of transcription factors perturbed by AKT1 activation. Finally, we show that commercially available AKT inhibitors can modulate the in vitro activity of various mutated forms. These results shed light on the pathogenesis of JGCTs and provide therapeutic leads for a targeted treatment.

Acute Isolated Paraplegia Revealing an Ewing Sarcoma of the Thoracic Spine.

Ewing sarcoma (ES) infrequently affects the spine. Diagnosis is usually made several weeks following growing symptoms. In this report, we present the case of a child with ES localized at the upper thoracic level. ES was revealed by isolated acute complete paraplegia mimicking medullary stroke. The girl was operated for decompressive laminectomy and tumor removal. Afterwards, she received adjuvant therapy. Subsequently, the child showed a slow improvement of her leg sensitivity associated with a partial motor recovery. ES can affect the mobile spine. Acute symptomatology due to intratumoral hemorrhage and sudden spinal cord compression may suggest the diagnosis. Neurological outcomes following ES are generally poor.

Congenital Infantile Fibrosarcoma Associated With a Lipofibromatosis-Like Component: One Train May Be Hiding Another.

Congenital infantile fibrosarcoma (CIFS) is a soft tissue sarcoma of infants mainly involving lower extremities and usually developing during the first year of life. At another end of the spectrum of pediatric fibroblastic lesions, lipofibromatosis is a rare benign infiltrative soft tissue tumor that affects children. The authors report in this study a particular presentation with a CIFS surrounded by lipofibromatosis-like areas. The presence of a surrounding benign tumor confused and delayed CIFS diagnosis.

DCDC2 Mutations Cause Neonatal Sclerosing Cholangitis.

Neonatal sclerosing cholangitis (NSC) is a rare biliary disease leading to liver transplantation in childhood. Patients with NSC and ichtyosis have already been identified with a CLDN1 mutation, encoding a tight-junction protein. However, for the majority of patients, the molecular basis of NSC remains unknown. We identified biallelic missense mutations or in-frame deletion in DCDC2 in four affected children. Mutations involve highly conserved amino acids in the doublecortin domains of the protein. In cholangiocytes, DCDC2 protein is normally located in the cytoplasm and cilia, whereas in patients the mutated protein is accumulated in the cytoplasm, absent from cilia, and associated with ciliogenesis defect. This is the first report of DCDC2 mutations in NSC. This data expands the molecular spectrum of NSC, that can be considered as a ciliopathy and also expands the clinical spectrum of the DCDC2 mutations, previously reported in dyslexia, deafness, and nephronophtisis.