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supplemental legend

Supplemental Table 2. Patient and tumor characteristics at time of diagnosis.

Supplemental Figure 2 CD171 tissue expression in rhesus shown by TMA.

Supplemental Table 1. Release criteria.

Supplemental Figure 1 CD171 tissue expression in human shown by TMA.

Purpose: The identification and vetting of cell surface tumor-restricted epitopes for chimeric antigen receptor (CAR)–redirected T-cell immunotherapy is the subject of intensive investigation. We have focused on CD171 (L1-CAM), an abundant cell surface molecule on neuroblastomas and, specifically, on the glycosylation-dependent tumor-specific epitope recognized by the CE7 monoclonal antibody.Experimental Design: CD171 expression was assessed by IHC using CE7 mAb in tumor microarrays of primary, metastatic, and recurrent neuroblastoma, as well as human and rhesus macaque tissue arrays. The safety of targeting the CE7 epitope of CD171 with CE7-CAR T cells was evaluated in a preclinical rhesus macaque trial on the basis of CD171 homology and CE7 cross reactivity. The feasibility of generating bioactive CAR T cells from heavily pretreated pediatric patients with recurrent/refractory disease was assessed.Results: CD171 is uniformly and abundantly expressed by neuroblastoma tumor specimens obtained at diagnoses and relapse independent of patient clinical risk group. CD171 expression in normal tissues is similar in humans and rhesus macaques. Infusion of up to 1 × 108/kg CE7-CAR+ CTLs in rhesus macaques revealed no signs of specific on-target off-tumor toxicity. Manufacturing of lentivirally transduced CD4+ and CD8+ CE7-CAR T-cell products under GMP was successful in 4 out of 5 consecutively enrolled neuroblastoma patients in a phase I study. All four CE7-CAR T-cell products demonstrated in vitro and in vivo antitumor activity.Conclusions: Our preclinical assessment of the CE7 epitope on CD171 supports its utility and safety as a CAR T-cell target for neuroblastoma immunotherapy. Clin Cancer Res; 23(2); 466–77. ©2016 AACR.

Supplemental Figure 4 Phenotypic analysis of initial and final patient products.

Supplemental Figure 3 Monitoring of NHPs after CAR T cell infusion.

Kaposiform hemangioendothelioma is classified as a locally aggressive vascular tumor of childhood resulting from abnormal angiogenesis and lymphangiogenesis. Most commonly, KHE presents as a single tissue mass, ranging from an erythematous papule to a violaceous indurated tumor. Definitive diagnosis requires tissue sampling with the demonstration of ill-defined nodules and fascicles of spindle-shaped D2-40 positive endothelial cells, forming slit-like vascular channels. This newborn presented with multifocal cutaneous Kaposiform hemangioendothelioma associated with Kasabach-Merritt phenomenon confirmed on histopathology with immunostaining.

Locoregional delivery of chimeric antigen receptor (CAR) T cells has resulted in objective responses in adults with glioblastoma, but the feasibility and tolerability of this approach is yet to be evaluated for pediatric central nervous system (CNS) tumors. Here we show that engineering of a medium-length CAR spacer enhances the therapeutic efficacy of human erb-b2 receptor tyrosine kinase 2 (HER2)-specific CAR T cells in an orthotopic xenograft medulloblastoma model. We translated these findings into BrainChild-01 ( NCT03500991 ), an ongoing phase 1 clinical trial at Seattle Children’s evaluating repetitive locoregional dosing of these HER2-specific CAR T cells to children and young adults with recurrent/refractory CNS tumors, including diffuse midline glioma. Primary objectives are assessing feasibility, safety and tolerability; secondary objectives include assessing CAR T cell distribution and disease response. In the outpatient setting, patients receive infusions via CNS catheter into either the tumor cavity or the ventricular system. The initial three patients experienced no dose-limiting toxicity and exhibited clinical, as well as correlative laboratory, evidence of local CNS immune activation, including high concentrations of CXCL10 and CCL2 in the cerebrospinal fluid. This interim report supports the feasibility of generating HER2-specific CAR T cells for repeated dosing regimens and suggests that their repeated intra-CNS delivery might be well tolerated and activate a localized immune response in pediatric and young adult patients. In an interim analysis of a phase 1 trial, repeated intracranial infusions of HER2-specific CAR T cells were well tolerated with no observed dose-limiting toxicities in three young adult patients with CNS tumors.

Objectives To determine significant histologic findings in tonsils and categorize clinical settings in which they occur to identify cases benefiting from histopathologic examination using a computer-based natural language search (NLS) applied to the electronic medical record. Methods The pathology database was queried for tonsillectomy cases accessioned between 2002 and 2018. Tonsils with microscopic examination were reviewed, and indication for examination and diagnoses were tallied. Clinical risk of malignancy was correlated with findings. A NLS was used to interrogate preoperative clinical records of the same group of patients. The search identified cases at risk of significant histologic findings and was implemented as part of standard practice. Results Of the 18,733 bilateral tonsillectomies identified in the pathology database, 494 were palatine tonsils that underwent microscopic examination, 134 had indications concerning for malignancy, and 14 had significant findings on histologic examination. When the NLS was applied to the medical record of the same group, 223 cases were identified as having risk of malignancy, including all flagged by surgeons and pathologists and 89 additional cases. Clinical implementation resulted in identification of all cases benefiting from examination. Conclusions A NLS applied to the electronic medical record to select tonsils for examination was superior to relying on surgeons and pathologists.

We report a patient without known preexisting liver disease who presented with hepatopulmonary syndrome (HPS) due to aberrant intrahepatic portal venous development leading to portosystemic shunting. Liver transplantation resulted in resolution of portal hypertension and HPS and sildenafil was safely tolerated in the treatment of persistent fatigue and hypoxemia. Twelve months later, patient has normal allograft function and has returned to normal activity.

Acute kidney injury (AKI) is seen in one-fifth of pediatric patients with COVID-19 requiring hospital admission, and is associated with increased morbidity, mortality, and residual kidney impairment. The majority of kidney pathology data in patients with COVID-19 is derived from adult case series and there is an overall lack of histologic data for most pediatric patients with COVID-19.We assembled a multi-institutional cohort of five unvaccinated pediatric patients with COVID-19 and associated kidney dysfunction with available histology.Three complex patients with current or prior SARS-CoV-2 infection had multifactorial thrombotic microangiopathy with clinical features of hemolytic uremic syndrome (in two) or disseminated intravascular coagulation (in one); one died and another developed chronic kidney disease stage 5. Two with recently preceding SARS-CoV-2 infection presented with nephrotic syndrome; one had IgA vasculitis and one had minimal change disease. Within a short follow-up time, none has returned to baseline kidney function.Although uncommon, COVID-19-associated kidney injury can have significant morbidity in the unvaccinated pediatric and adolescent population. A higher resolution version of the Graphical abstract is available as Supplementary information.

Disorganized morphogenesis of arteries, veins, capillaries, and lymphatic vessels results in vascular malformations. Most individuals with isolated vascular malformations have postzygotic (mosaic), activating pathogenic variants in a handful of oncogenes within the PI3K–RAS–MAPK pathway (Padia et al., Laryngoscope Investig Otolaryngol 4: 170–173 [2019]). Activating pathogenic variants in the gene PIK3CA, which encodes for the catalytic subunit of phosphatidylinositol 3-kinase, are present in both lymphatic and venous malformations as well as arteriovenous malformations in other complex disorders such as CLOVES syndrome (congenital, lipomatous, overgrowth, vascular malformations, epidermal anevi, scoliosis) (Luks et al., Pediatr Dev Pathol 16: 51 [2013]; Luks et al., J Pediatr 166: 1048–1054.e1–5 [2015]; Al-Olabi et al., J Clin Invest 128: 1496–1508 [2018]). These vascular malformations are part of the PIK3CA-related overgrowth spectrum, a spectrum of entities that have regionalized disordered growth due to the presence of tissue-restricted postzygotic PIK3CA pathogenic variants (Keppler-Noreuil et al., Am J Med Genet A 167A: 287–295 [2015]). Cerebrofacial vascular metameric syndrome (CVMS; also described as cerebrofacial arteriovenous metameric syndrome, Bonnet–Dechaume–Blanc syndrome, and Wyburn–Mason syndrome) is the association of retinal, facial, and cerebral vascular malformations (Bhattacharya et al., Interv Neuroradiol 7: 5–17 [2001]; Krings et al., Neuroimaging Clin N Am 17: 245–258 [2007]). The segmental distribution, the presence of tissue overgrowth, and the absence of familial recurrence are all consistent with CVMS being caused by a postzygotic mutation, which has been hypothesized by previous authors (Brinjiki et al., Am J Neuroradiol 39: 2103–2107 [2018]). However, the genetic cause of CVMS has not yet been described. Here, we present three individuals with CVMS and mosaic activating pathogenic variants within the gene PIK3CA. We propose that CVMS be recognized as part of the PIK3CA-related overgrowth spectrum, providing justification for future trials using pharmacologic PIK3CA inhibitors (e.g., alpelisib) for these difficult-to-treat patients.

Germline stop-gain variants in SAMD9L encode truncated gain-of-function proteins that result in a multisystem human disorder with autoinflammatory features. The interferon-inducible dominant proteins interfere with global protein synthesis via inhibition of translational elongation., SAMD9L is an interferon-induced tumor suppressor implicated in a spectrum of multisystem disorders, including risk for myeloid malignancies and immune deficiency. We identified a heterozygous de novo frameshift variant in SAMD9L in an infant with B cell aplasia and clinical autoinflammatory features who died from respiratory failure with chronic rhinovirus infection. Autopsy demonstrated absent bone marrow and peripheral B cells as well as selective loss of Langerhans and Purkinje cells. The frameshift variant led to expression of a truncated protein with interferon treatment. This protein exhibited a gain-of-function phenotype, resulting in interference in global protein synthesis via inhibition of translational elongation. Using a mutational scan, we identified a region within SAMD9L where stop-gain variants trigger a similar translational arrest. SAMD9L variants that globally suppress translation had no effect or increased mRNA transcription. The complex-reported phenotype likely reflects lineage-dominant sensitivities to this translation block. Taken together, our findings indicate that interferon-triggered SAMD9L gain-of-function variants globally suppress translation.

Locoregional delivery of chimeric antigen receptor (CAR) T cells has resulted in objective responses in adults with glioblastoma, but the feasibility and tolerability of this approach is yet to be evaluated for pediatric central nervous system (CNS) tumors. Here we show that engineering of a medium-length CAR spacer enhances the therapeutic efficacy of human erb-b2 receptor tyrosine kinase 2 (HER2)-specific CAR T cells in an orthotopic xenograft medulloblastoma model. We translated these findings into BrainChild-01 ( NCT03500991 ), an ongoing phase 1 clinical trial at Seattle Children's evaluating repetitive locoregional dosing of these HER2-specific CAR T cells to children and young adults with recurrent/refractory CNS tumors, including diffuse midline glioma. Primary objectives are assessing feasibility, safety and tolerability; secondary objectives include assessing CAR T cell distribution and disease response. In the outpatient setting, patients receive infusions via CNS catheter into either the tumor cavity or the ventricular system. The initial three patients experienced no dose-limiting toxicity and exhibited clinical, as well as correlative laboratory, evidence of local CNS immune activation, including high concentrations of CXCL10 and CCL2 in the cerebrospinal fluid. This interim report supports the feasibility of generating HER2-specific CAR T cells for repeated dosing regimens and suggests that their repeated intra-CNS delivery might be well tolerated and activate a localized immune response in pediatric and young adult patients.

BACKGROUND. Undifferentiated systemic autoinflammatory diseases (USAIDs) present diagnostic and therapeutic challenges. Chronic interferon (IFN) signaling and cytokine dysregulation may identify diseases with available targeted treatments. METHODS. Sixty-six consecutively referred USAID patients underwent underwent screening for the presence of an interferon signature using a standardized type-I IFN-response-gene score (IRG-S), cytokine profiling, and genetic evaluation by next-generation sequencing. RESULTS. Thirty-six USAID patients (55%) had elevated IRG-S. Neutrophilic panniculitis (40% vs. 0%), basal ganglia calcifications (46% vs. 0%), interstitial lung disease (47% vs. 5%), and myositis (60% vs. 10%) were more prevalent in patients with elevated IRG-S. Moderate IRG-S elevation and highly elevated serum IL-18 distinguished 8 patients with pulmonary alveolar proteinosis (PAP) and recurrent macrophage activation syndrome (MAS). Among patients with panniculitis and progressive cytopenias, 2 patients were compound heterozygous for potentially novel LRBA mutations, 4 patients harbored potentially novel splice variants in IKBKG (which encodes NF-κB essential modulator [NEMO]), and 6 patients had de novo frameshift mutations in SAMD9L. Of additional 12 patients with elevated IRG-S and CANDLE-, SAVI- or Aicardi-Goutières syndrome-like (AGS-like) phenotypes, 5 patients carried mutations in either SAMHD1, TREX1, PSMB8, or PSMG2. Two patients had anti-MDA5 autoantibody-positive juvenile dermatomyositis, and 7 could not be classified. Patients with LRBA, IKBKG, and SAMD9L mutations showed a pattern of IRG elevation that suggests prominent NF-κB activation different from the canonical interferonopathies CANDLE, SAVI, and AGS. CONCLUSIONS. In patients with elevated IRG-S, we identified characteristic clinical features and 3 additional autoinflammatory diseases: IL-18-mediated PAP and recurrent MAS (IL-18PAP-MAS), NEMO deleted exon 5-autoinflammatory syndrome (NEMO-NDAS), and SAMD9L-associated autoinflammatory disease (SAMD9L-SAAD). The IRG-S expands the diagnostic armamentarium in evaluating USAIDs and points to different pathways regulating IRG expression. Fil: de Jesus, Adriana A.. National Institute Of Allergy And Infectious Diseases; Estados Unidos Fil: Hou, Yangfeng. Shandong University; China Fil: Brooks, Stephen. National Institute Of Arthritis And Musculoskeletal And Skin Diseases; Estados Unidos Fil: Malle, Louise. cahn School of Medicine at Mount Sinai; Estados Unidos Fil: Biancotto, Angelique. No especifíca; Fil: Huang, Yan. National Institute Of Allergy And Infectious Diseases; Estados Unidos Fil: Calvo, Katherine R.. National Institutes of Health; Estados Unidos Fil: Marrero, Bernadette. No especifíca; Fil: Moir, Susan. No especifíca; Fil: Oler, Andrew J.. National Institute Of Allergy And Infectious Diseases ; Estados Unidos Fil: Deng, Zuoming. National Institute Of Arthritis And Musculoskeletal And Skin Diseases; Estados Unidos Fil: Montealegre Sanchez, Gina A.. National Institute Of Allergy And Infectious Diseases ; Estados Unidos Fil: Ahmed, Amina. No especifíca; Fil: Allenspach, Eric. Washington State University; Estados Unidos Fil: Arabshahi, Bita. Virginia Commonwealth University; Estados Unidos Fil: Behrens, Edward. University of Pennsylvania; Estados Unidos Fil: Benseler, Susanne. University of Calgary; Canadá Fil: Bezrodnik, Liliana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Bout Tabaku, Sharon. No especifíca; Fil: Brescia, AnneMarie C.. No especifíca; Fil: Brown, Diane. No especifíca; Fil: Burnham, Jon M.. University of Pennsylvania; Estados Unidos Fil: Caldirola, Maria Soledad. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Gobierno de la Ciudad de Buenos Aires. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas; Argentina Fil: Carrasco, Ruy. No especifíca; Fil: Chan, Alice Y.. University of California; Estados Unidos Fil: Cimaz, Rolando. Università degli Studi di Milano; Italia Fil: Dancey, Paul. Janeway Children's Hospital And Rehabilitation Centre; Canadá Fil: Dare, Jason. University of Arkansas for Medical Sciences; Estados Unidos Fil: DeGuzman, Marietta. Baylor College Of Medicine; Estados Unidos Fil: Dimitriades, Victoria. No especifíca; Fil: Ferguson, Ian. University of Yale. School of Medicine; Estados Unidos Fil: Ferguson, Polly. University of Iowa; Estados Unidos Fil: Finn, Laura. University of Washington; Estados Unidos Fil: Gattorno, Marco. No especifíca; Fil: Grom, Alexei A.. No especifíca; Fil: Hanson, Eric P.. No especifíca; Fil: Hashkes, Philip J.. No especifíca; Fil: Hedrich, Christian M.. University of Liverpool; Reino Unido Fil: Herzog, Ronit. University of New York; Estados Unidos Fil: Horneff, Gerd. Universitat zu Köln; Alemania Fil: Jerath, Rita. Augusta University; Estados Unidos Fil: Kessler, Elizabeth. University of Missouri; Estados Unidos Fil: Kim, Hanna. No especifíca; Fil: Kingsbury, Daniel J.. No especifíca; Fil: Laxer, Ronald M.. University Of Toronto. Hospital For Sick Children; Canadá Fil: Lee, Pui Y.. Children's Hospital Boston; Estados Unidos Fil: Lee Kirsch, Min Ae. Technische Universität Dresden; Alemania Fil: Lewandowski, Laura. No especifíca; Fil: Li, Suzanne. Hackensack University Medical Center; Estados Unidos Fil: Lilleby, Vibke. Oslo University Hospital; Noruega Fil: Mammadova, Vafa. Azerbaijan Medical University; Azerbaiyán Fil: Moorthy, Lakshmi N.. Robert Wood Johnson Medical School; Estados Unidos Fil: Nasrullayeva, Gulnara. Azerbaijan Medical University; Azerbaiyán Fil: O'Neil, Kathleen M.. Riley Hospital for Children; Estados Unidos Fil: Onel, Karen. Hospital for Special Surgery; Estados Unidos Fil: Ozen, Seza. Hacettepe University; Turquía Fil: Pan, Nancy. Hospital for Special Surgery; Estados Unidos Fil: Pillet, Pascal. Children Hospital Pellegrin-Enfants; Francia Fil: Piotto, Daniela G.P.. Universidade Federal de Sao Paulo; Brasil Fil: Punaro, Marilynn G.. University of Texas; Estados Unidos Fil: Reiff, Andreas. University of Nebraska; Estados Unidos Fil: Reinhardt, Adam. University of Nebraska; Estados Unidos Fil: Rider, Lisa G.. No especifíca; Fil: Rivas Chacon, Rafael. Nicklaus Children’s Hospital; Estados Unidos Fil: Ronis, Tova. Children’s National Health System; Estados Unidos Fil: Rösen Wolff, Angela. Technische Universität Dresden; Alemania Fil: Roth, Johannes. Children’s Hospital of Eastern Ontario; Canadá Fil: Mckerran Ruth, Natasha. Medical University of South Carolina; Estados Unidos Fil: Rygg, Marite. Norwegian University of Science and Technology; Noruega Fil: Schmeling, Heinrike. University of Calgary; Canadá Fil: Schulert, Grant. Children’s Hospital Medical Center; Estados Unidos Fil: Scott, Christiaan. University of Cape Town; Sudáfrica Fil: Seminario, Gisella. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina Fil: Shulman, Andrew. University of California at Irvine; Estados Unidos Fil: Sivaraman, Vidya. Nationwide Children’s Hospital; Estados Unidos Fil: Son, Mary Beth. Boston Children’s Hospital; Estados Unidos Fil: Stepanovskiy, Yuriy. Shupyk National Medical Academy for Postgraduate Education; Ucrania Fil: Stringer, Elizabeth. Dalhousie University Halifax; Canadá Fil: Taber, Sara. Hospital for Special Surgery; Estados Unidos Fil: Terreri, Maria Teresa. Universidade Federal de Sao Paulo; Brasil Fil: Tifft, Cynthia. No especifíca; Fil: Torgerson, Troy. University of Washington; Estados Unidos Fil: Tosi, Laura. Children’s National Health System; Estados Unidos Fil: van Royen Kerkhof, Annet. Wilhelmina Children’s Hospital Utrech; Países Bajos Fil: Wampler Muskardin, Theresa. New York University School of Medicine; Estados Unidos Fil: Canna, Scott W.. University of Pittsburgh; Estados Unidos Fil: Goldbach Mansky, Raphaela. National Institute Of Allergy And Infectious Diseases ; Estados Unidos

Published histologic studies of the hilar plate or entire biliary remnant at the time of Kasai portoenterostomy (KHPE) have not provided deep insight into the pathogenesis of biliary atresia, relation to age at surgery, prognosis or the basis for successful drainage. We report detailed histologic findings in 172 centrally reviewed biliary remnants with an average of 6 sections per subject. Active lesions were classified as either necroinflammatory (rare/clustered in a few subjects) or active concentric fibroplasia with or without inflammation (common). Inactive lesions showed bland replacement by collagen and fibrous cords with little or no inflammation. Heterogeneity was common within a given remnant; however, relatively homogenous histologic patterns, defined as 3 or more inactive or active levels in the hepatic ducts levels, characterized most remnants. Homogeneity did not correlate with age at KHPE, presence/absence of congenital anomalies at laparotomy indicative of heterotaxy and outcome. Remnants from youngest subjects were more likely than older subjects to be homogenously inactive suggesting significantly earlier onset in the youngest subset. Conversely remnants from the oldest subjects were often homogenously active suggesting later onset or slower progression. More data are needed in remnants from subjects

The development of de novo donor-specific antibodies (dnDSA) has been associated with rejection and graft loss in kidney transplantation, and DSA screening is now recommended in all kidney transplant recipients. However, the clinical significance of dnDSA detected by screening patients with a stable creatinine remains unclear.One hundred three patients younger than 18years receiving a first, kidney alone transplant between December 1, 2007, and December 31, 2013, underwent DSA screening every 3months for 2years posttransplant, with additional testing as clinically indicated. No treatment was given for DSAs in the absence of biopsy-proven rejection.Twenty (19%) patients had dnDSA first detected on a screening test, and 13 (13%) patients had dnDSA first detected on a for-cause test. Mean follow-up time posttransplant was 4.4years. Screening-detected dnDSA was associated with an increased risk of rejection within 3years, microvascular inflammation, and C4d staining on a 2-year protocol biopsy. In a Cox proportional hazards regression, screening-detected dnDSA was not associated with time to 30% decline in estimated glomerular filtration rate (adjusted hazard ratio, 0.88; 95% confidence interval [CI], 0.30-2.00; P=0.598) or graft loss. dnDSA first detected on for-cause testing was associated with a 2.8 times increased risk of decline in graft function (95% CI, 1.08-7.27; P=0.034) and a 7.34 times increased risk of graft loss (95% CI, 1.37-39.23 P=0.020) compared with those who did not develop dnDSA.The clinical setting in which dnDSA is first detected impacts the association between dnDSA and graft function. Further research is needed to clarify the role of dnDSA screening in pediatric kidney transplantation.

Background Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of CKD. The discovery of monogenic causes of SRNS has revealed specific pathogenetic pathways, but these monogenic causes do not explain all cases of SRNS. Methods To identify novel monogenic causes of SRNS, we screened 665 patients by whole-exome sequencing. We then evaluated the in vitro functional significance of two genes and the mutations therein that we discovered through this sequencing and conducted complementary studies in podocyte-like Drosophila nephrocytes. Results We identified conserved, homozygous missense mutations of GAPVD1 in two families with early-onset NS and a homozygous missense mutation of ANKFY1 in two siblings with SRNS. GAPVD1 and ANKFY1 interact with the endosomal regulator RAB5. Coimmunoprecipitation assays indicated interaction between GAPVD1 and ANKFY1 proteins, which also colocalized when expressed in HEK293T cells. Silencing either protein diminished the podocyte migration rate. Compared with wild-type GAPVD1 and ANKFY1, the mutated proteins produced upon ectopic expression of GAPVD1 or ANKFY1 bearing the patient-derived mutations exhibited altered binding affinity for active RAB5 and reduced ability to rescue the knockout-induced defect in podocyte migration. Coimmunoprecipitation assays further demonstrated a physical interaction between nephrin and GAPVD1, and immunofluorescence revealed partial colocalization of these proteins in rat glomeruli. The patient-derived GAPVD1 mutations reduced nephrin-GAPVD1 binding affinity. In Drosophila , silencing Gapvd1 impaired endocytosis and caused mistrafficking of the nephrin ortholog. Conclusions Mutations in GAPVD1 and probably in ANKFY1 are novel monogenic causes of NS. The discovery of these genes implicates RAB5 regulation in the pathogenesis of human NS.

BACKGROUND: Nephrotic syndrome can be caused by a subgroup of mitochondrial diseases classified as primary coenzyme Q(10) (CoQ(10)) deficiency. Pathogenic COQ2 variants are a cause of primary CoQ(10) deficiency and present with phenotypes ranging from isolated nephrotic syndrome to fatal multisystem disease. CASE REPORT: We report three pediatric patients with COQ2 variants presenting with nephrotic syndrome. Two of these patients had normal leukocyte CoQ(10) levels prior to treatment. Pathologic findings varied from mesangial sclerosis to focal segmental glomerulosclerosis, with all patients having abnormal appearing mitochondria on kidney biopsy. In two of three patients treated with CoQ(10) supplementation, the nephrotic syndrome resolved and at follow-up both have normal renal function and stable proteinuria. CONCLUSIONS: COQ2 nephropathy should be suspected in patients presenting with nephrotic syndrome, although less common than disease due to mutations in NPHS1, NPHS2, and WT1. The index of suspicion should remain high and we suggest that providers consider genetic evaluation even in patients with normal leukocyte CoQ(10) levels, as levels may be within normal range even with significant clinical disease. Early molecular diagnosis and specific treatment are essential in the management of this severe yet treatable condition.

Tissue mimics are of great interest in understanding diseases. Here, organoids were developed that resemble polycystic kidney disease cysts and it was demonstrated how material environment and adhesion can affect cystogenesis and disease progression. Polycystic kidney disease (PKD) is a life-threatening disorder, commonly caused by defects in polycystin-1 (PC1) or polycystin-2 (PC2), in which tubular epithelia form fluid-filled cysts1,2. A major barrier to understanding PKD is the absence of human cellular models that accurately and efficiently recapitulate cystogenesis3,4. Previously, we have generated a genetic model of PKD using human pluripotent stem cells and derived kidney organoids5,6. Here we show that systematic substitution of physical components can dramatically increase or decrease cyst formation, unveiling a critical role for microenvironment in PKD. Removal of adherent cues increases cystogenesis 10-fold, producing cysts phenotypically resembling PKD that expand massively to 1-centimetre diameters. Removal of stroma enables outgrowth of PKD cell lines, which exhibit defects in PC1 expression and collagen compaction. Cyclic adenosine monophosphate (cAMP), when added, induces cysts in both PKD organoids and controls. These biomaterials establish a highly efficient model of PKD cystogenesis that directly implicates the microenvironment at the earliest stages of the disease.

Chimeric antigen receptor (CAR) T cell therapy provides a broadly applicable, targeted, yet pathway-independent, intervention for pediatric central nervous system (CNS) tumors. We have optimized the efficacy and specificity of a HER2-targeted CAR with an extracellular target-specific scFv domain derived from trastuzumab (a HER2 targeting antibody), a co-expressed truncated EGFR (EGFRt) to evaluate transduction efficacy and as a potential suicide mechanism with cetuximab treatment, and a medium-length spacer coupled to an intracellular 4-1BBζ domain. In vitro studies revealed antigen specific cytotoxicity and cytokine release against HER2-positive CNS tumors; and the HER2CAR significantly improved survival (p=0.003) in vivo at 90 days in a xenograft CNS model relative to Mock-treated controls. BrainChild-01 is a first-in-human trial evaluating locoregional infusion of HER2CAR T cells for children and young adults with HER2-positive progressive or recurrent CNS tumors. Autologous T cells are apheresed, engineered to express the second-generation HER2CAR, and expanded ex vivo. They are delivered via indwelling CNS catheter into either the tumor cavity (Arm A) or ventricular system (Arm B) using an intra-patient dose-escalation regimen with weekly dosing for 3 of every 4 weeks per course. The study period is two courses though subjects may receive up to six. Subject 001, a 19-year-old female with a parietal lobe hypermutated HER2-positive anaplastic astrocytoma (WHO grade III), enrolled on Arm A following third progression, underwent apheresis and successful production of 1.9 x 10(9) HER2CAR T cells. She tolerated the study-prescribed six CAR T cell doses over two courses at doses of 1 x 10(7) to 2.5 x 10(7) without dose limiting toxicity. Acute local inflammation and CRP elevation followed each dose. MRI brain/spine obtained after Course 2 revealed increased enhancement and T2/FLAIR hyperintensity surrounding the tumor cavity with mildly increased mass effect, indeterminate for treatment-related inflammatory changes/pseudoprogression versus tumor progression. Enrollment is ongoing.

Purpose: The identification and vetting of cell surface tumor-restricted epitopes for chimeric antigen receptor (CAR)–redirected T-cell immunotherapy is the subject of intensive investigation. We have focused on CD171 (L1-CAM), an abundant cell surface molecule on neuroblastomas and, specifically, on the glycosylation-dependent tumor-specific epitope recognized by the CE7 monoclonal antibody. Experimental Design: CD171 expression was assessed by IHC using CE7 mAb in tumor microarrays of primary, metastatic, and recurrent neuroblastoma, as well as human and rhesus macaque tissue arrays. The safety of targeting the CE7 epitope of CD171 with CE7-CAR T cells was evaluated in a preclinical rhesus macaque trial on the basis of CD171 homology and CE7 cross reactivity. The feasibility of generating bioactive CAR T cells from heavily pretreated pediatric patients with recurrent/refractory disease was assessed. Results: CD171 is uniformly and abundantly expressed by neuroblastoma tumor specimens obtained at diagnoses and relapse independent of patient clinical risk group. CD171 expression in normal tissues is similar in humans and rhesus macaques. Infusion of up to 1 × 108/kg CE7-CAR+ CTLs in rhesus macaques revealed no signs of specific on-target off-tumor toxicity. Manufacturing of lentivirally transduced CD4+ and CD8+ CE7-CAR T-cell products under GMP was successful in 4 out of 5 consecutively enrolled neuroblastoma patients in a phase I study. All four CE7-CAR T-cell products demonstrated in vitro and in vivo antitumor activity. Conclusions: Our preclinical assessment of the CE7 epitope on CD171 supports its utility and safety as a CAR T-cell target for neuroblastoma immunotherapy. Clin Cancer Res; 23(2); 466–77. ©2016 AACR.

Introduction: While many data have been emerging regarding the outcomes of cancer patients infected with SARS-CoV-2 and their increased risk of mortality, emphasis on patients with hematologic malignancies and how they have been affected during this pandemic is lacking. Louisiana, particularly New Orleans, one of the pandemic epicenters, has a higher-than-average cancer diagnosis rate of multiple myeloma as well as cancer-related deaths. Ochsner Cancer Institute was fortunately prepared for the crisis, which allowed our center to continue taking care of both inpatients and outpatients as needed during the pandemic. Hence, we accumulated ample data among cancer patients and the effects of COVID-19. Here we provide novel initial mortality data on multiple myeloma patients infected with SARS-CoV-2. Methods: Our retrospective, electronic medical record review included 15 patients with a history of multiple myeloma who tested positive for SARS-CoV-2 PCR from March 1st to April 30th, 2020. Medical records were reviewed for inpatient/outpatient status of infection, outcome of infection, multiple myeloma disease and treatment history, and history of autologous stem cell transplant. Results: Out of the 15 patients infected, there were 6 deaths (40%). A total of 11 patients were on active treatment, including all 6 patients who died (54.5%), though active treatment did not appear to be a significant risk factor when compared to off-therapy patients (p=.103). Patients older than 65 years seem to be at increased risk of death when compared to patients less than 65 years of age (p=.011). Hospitalized patients were more likely to succumb to infection compared to non-hospitalized patients (p=.044). Of the 15 patients, 4 had a history of autologous stem cell transplant and this was not found to affect mortality (p=.103). Chronic kidney disease was present in 7 patients and did not appear to impact mortality (p=.315). Of these (n=9), 7 patients had hypogammaglobulinemia and 5 of these patients died (71.4%). Overall, 5 of the 6 patients who died were found to have hypogammaglobulinemia (the 6th death did not have immunoglobulins eligible for review). However, the presence of hypogammaglobulinemia did not appear to increase mortality overall (p=.167). Conclusion: Patients older than 65 years of age with a history of multiple myeloma seem to be at risk of death from COVID-19. Interestingly, a history of autologous stem cell transplant did not appear to affect mortality. While the presence of hypogammaglobulinemia did not affect mortality, its overwhelming finding in the patients who died warrants further discussion in the future. Larger studies are needed to expand on these findings and uncover further characteristics to help stratify at-risk patients in the future. Citation Format: Michael John Lunski, Karine Tawagi, Diana Maslov, Laura Finn. Outcomes of patients with multiple myeloma with COVID-19 infection [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr PO-081.

There are numerous causes of acute and chronic kidney disease following HSCT. Excluding nephrotoxic drugs and infections, the role of GVHD in the genesis of several glomerulopathies is a controversial or incompletely understood subject. Transplant-associated thrombotic microangiopathy (TA-TMA) has been associated with exposure to calcineurin inhibitors (CNIs) in earlier studies, and more recent studies have demonstrated associations with GVHD. Many of these processes can coexist, making etiologic determination difficult. The development of TA-TMA has not been conclusively linked with the use of high-dose conditioning regimens nor has a clear or consistent response to anticomplement treatment (e.g., eculizumab) been observed. Other post-HSCT glomerulopathies associated with nephrotic syndrome include membranous nephropathy, minimal change disease, and focal segmental glomerulosclerosis (FSGS). The potential mechanisms of GVHD’s role in kidney injury, e.g., the contributions of T cells, macrophages, cytokines, and immune responses against kidney proteins, require further investigation.

Summary Immunoglobulin A (IgA)–dominant membranoproliferative glomerulonephritis (MPGN) is a descriptive term for renal biopsies in which differential diagnoses of unusual IgA nephropathy (IgAN), infection-related GN, or other etiologies are considered. We sought to understand clinical and pathologic features of this finding. Native kidney biopsies with IgA-dominant immune deposits and diffuse MPGN features without significant exudative features or subepithelial deposits were retrospectively reviewed. Two groups (n = 27, 33 biopsies) were identified: patients with chronic liver disease and those without. Patients without chronic liver disease (n = 15) were men (73%, age 40) who presented with nephrotic-range proteinuria, hematuria, renal insufficiency, negative serologic studies, and no history of infection. At a median interval of 3 years, 11 had available follow-up information. Three (27%) progressed to end-stage renal disease. One had recurrent IgA-dominant GN in the renal allograft less than 1 year posttransplant. Four of 5 patients with repeat biopsies had persistent IgA-dominant MPGN. Patients with chronic liver disease (n = 12) had similar biopsy findings, but 42% had concurrent infections, some occult. At a median interval of 7 weeks, 8 patients (80% of those with follow-up) had died and 2 were dialysis dependent. In conclusion, IgA-dominant MPGN was seen in 2 clinical cohorts in this study. In patients without chronic liver disease, this appears to represent either a unique clinicopathologic entity with a poorer prognosis than IgAN or an aggressive variant of IgAN. Patients with chronic liver disease often have underlying infection, and regardless of treatment, die within 1 year because of complex medical conditions.

We hypothesized that if infection is the proximate cause of congenital biliary atresia, an appropriate response to antigen would occur in lymph nodes contiguous with the biliary remnant. We compared the number of follicular germinal centers (GC) in 79 surgically excised hilar lymph nodes (LN) and 27 incidentally discovered cystic duct lymph nodes (CDLN) in 84 subjects at the time of hepatic portoenterostomy (HPE) for biliary atresia (BA) to autopsy controls from the pancreaticobiliary region of non-septic infants > 3 months old at death. All 27 control LN lacked GC a sign in infants of a primary response to antigenic stimulation. GC were found in 53% of 106 LN in 56 of 84 subjects. Presence of GC and number of GC/LN was unrelated to age at onset of jaundice but was related to older age at HPE. Absent GC in visible and incidentally removed CDLN predicted survival with the native liver at 2 and 3 years after HPE, p=0.03, but significance was lost at longer intervals. Visible surgically excised LN contiguous with the most proximal biliary remnants had one or more well-formed reactive GC in only 26/51 subjects. No correlation existed between GC in hilar LN and frank inflammatory activity in the proximal hepatic duct, or between the latter and outcome after HPE. GC in hilar LN correlated with generalized neutrophilic pericholangitis in 80 contemporaneous liver biopsies (p=0.04) but not with overall intensity of portal cellular infiltrates. The absence of consistent evidence of antigenic stimulation in LN contiguous with the biliary remnant argues for a limited role for infection in the etiology of biliary atresia. The intense inflammatory lesions occasionally found in remnants and the acute pericholangitis found in a minority of liver biopsies could be secondary either to bile-induced injury or secondary infection established as obstruction evolves.

Graft-versus-host disease (GVHD) is associated with kidney injury after hematopoietic cell transplantation (HCT). Because plasma elafin levels correlate with skin GVHD, this study examined urinary elafin as a potential marker of renal inflammation and injury.Urine was collected prospectively on 205 patients undergoing their first HCT from 2003 to 2010. Collections were done at baseline, weekly through day 100, and monthly through year 1 to measure elafin and urine albumin-to-creatinine ratio (ACR). Associations between urinary elafin levels and microalbuminuria, macroalbuminuria, AKI and CKD, and mortality were examined using Cox proportional hazards or linear regression models. Available kidney biopsy specimens were processed for immunohistochemistry.Mean urinary elafin levels to day 100 were higher in patients with micro- or macroalbuminuria (adjusted mean difference, 529 pg/ml; P=0.03) at day 100 than in those with a normal ACR (adjusted mean difference, 1295 pg/ml; P0.001). Mean urinary elafin levels were higher in patients with AKI compared with patients without AKI (adjusted mean difference, 558 pg/ml; P0.01). The average urinary elafin levels within the first 100 days after HCT were higher in patients who developed CKD at 1 year than in patients without CKD (adjusted mean difference, 894 pg/ml; P=0.002). Among allogeneic recipients, a higher proportion of patients with micro- or macroalbuminuria at day 100 also had grade II-IV acute GVHD (80% and 86%, respectively) compared with patients with a normal ACR (58%; global P0.01). Each increase in elafin of 500 pg/ml resulted in a 10% increase in risk of persistent macroalbuminuria (hazard ratio, 1.10; 95% confidence interval [95% CI], 1.06 to 1.13; P0.001) and a 7% increase in the risk of overall mortality (95% CI, 1.02 to 1.13, P0.01). Renal biopsy specimens from a separate cohort of HCT survivors demonstrated elafin staining in distal and collecting duct tubules.Higher urinary elafin levels are associated with an increased risk of micro- and macroalbuminuria, AKI and CKD, and death after HCT.

Glypican 3 (GPC3), a heparan sulfate proteoglycan, plays a role in cell growth and differentiation. Mutations of the GPC3 gene are responsible for Simpson-Golabi-Behmel syndrome, which is characterized by anomalies of postnatal overgrowth and an increased risk of developing pediatric malignancies, mostly Wilms tumor and liver cancer. In order to understand the possible role of GPC3 in renal development and Wilms tumor formation, we analyzed messenger RNA (mRNA) and protein levels of GPC3 in sporadic Wilms tumors and compared it to normal kidneys and other common renal epithelial tumors. By using Affymetrix HGU133 oligonucleotide gene expression microarray data from 191 renal tumors and 12 normal kidneys, we found significant overexpression of GPC3 in Wilms tumors (p < 0.01), with 3.5-fold higher expression in comparison to normal kidneys and 6.5-fold higher than any type of renal tumors. The GPC3 gene product in Wilms tumor was further evaluated by immunohistochemistry and quantified by an automated image analysis. Cytoplasmic and membranous GPC3 immunoreactivity was present in 77 % of primary Wilms tumors (23/30), 93 % of metastatic Wilms tumors (13/14), 50 % of metanephric adenomas (4/8), 33 % of congenital mesoblastic nephromas (2/6), 100 % of nephrogenic rests (11/11), and 100 % of fetal kidneys (5/5). GPC3 staining was predominantly identified in blastemal and epithelial components of Wilms tumors, similar to that of fetal non-neoplastic kidney. All adult renal tumors (n = 60) and normal kidneys (n = 15) were GPC3 negative. These findings suggest the utility of GPC3 in differential diagnosis and follow-up of Wilms tumors. Our data also indicate that GPC3 is an oncofetal protein with a potential therapeutic value.

Purpose To elucidate the mechanisms underlying failed nasolacrimal duct (NLD) probing in children with Down syndrome (DS) utilizing computed tomography (CT) scans and histopathology of nasal mucosa. Methods The medical records of children with DS and NLD obstruction confirmed by dye disappearance testing who failed NLD surgery were retrospectively reviewed. Dimensions of the bony NLD and presence of postductal mucosal obstruction were obtained from CT scans. Histopathology of the nasal mucosa was performed in a subset of patients. Subsequent treatment was topical or intranasal corticosteroids or submucosal corticosteroids alone or combined with surgical reduction of the inferior turbinate. Results A total of 9 subjects (age range, 8-10 years) and 43 age-matched controls were included. Both groups demonstrated a logarithmic increase in NLD and maxilla dimensions with increasing age; however, the transverse diameter of the NLD was consistently 1-2 mm smaller in children with DS ≤5 years age (n = 4) than in age-matched controls. The transverse diameter in DS children overlapped that of controls after 5 years age. Histopathology revealed abnormal lymphoplasmacytic inflammation of the mucosa in 4 of 5 biopsies of DS patients, consistent with chronic infection, allergic disease, or immune dysregulation. The postductal obstruction was successfully treated with topical or intranasal corticosteroids or by surgical reduction of the inferior turbinate submucosa with corticosteroid injection. Conclusions Before 5 years of age, NLD obstruction in children with DS was associated with reduced dimensions of the NLD and hypertrophic nasal mucosa. In DS children older than 5 years of age, the dimensions of the NLD are normal and postductal obstruction due to hypertrophic nasal mucosa should be considered.

Chimeric antigen receptor (CAR) T-cell therapy carries the promise of a broadly applicable, targeted, yet molecular pathway-independent, intervention for pediatric central nervous system (CNS) tumors. The BrainChild pipeline at Seattle Children’s utilizes engineered CAR T-cells directed against the surface epitopes HER2, EGFR, B7-H3 and IL13Ralpha2, which are commonly expressed in pediatric CNS tumors including high-grade glioma, diffuse intrinsic pontine glioma, medulloblastoma, and ependymoma. Using in vitro and in vivo preclinical modeling, we have optimized the efficacy and specificity of the CAR constructs. The extracellular target-specific scFv domain for the HER2-specific and EGFR-specific CARs are derived from trastuzumab and an EGFR806 antibody, respectively. Third-generation CAR T-cells with medium-length (HER2-CAR) and short (EGFR806-CAR) spacers coupled to an intracellular 4-1BBζ domain result in complete and durable tumor eradication in mouse xenograft CNS tumor models. We now are poised to begin enrolling Phase 1 clinical trials for children and young adults with recurrent or refractory CNS tumors expressing the respective target epitopes. We will deliver locoregional adoptive therapy with autologous CD4 and CD8 T cells lentivirally transduced with the optimized CAR constructs. Using a dose-escalation regimen, CAR T-cells will be injected on a weekly schedule via indwelling catheters into the tumor resection cavity or the ventricular system. The primary objectives are safety and feasibility, along with secondary and exploratory objectives to define the CAR T-cell distribution in the CSF and peripheral circulation, target epitope expression across tumor populations, progression free and overall survival, and biomarkers of anti-tumor CAR T-cell activity.

Desmoplastic small-round-cell tumors are rare aggressive malignancies that belong to the "small round blue cell" tumor family. They predominantly affect the abdomen in adolescent and young adult males. Computed tomography is currently the modality of choice both for diagnosis and follow-up assessment. In this review, the authors provide a concise yet comprehensive discussion of this condition with emphasis on the imaging findings. Pathologic correlation, differential diagnostic considerations, and treatment will also be presented.

The liver biopsy guides diagnostic investigation and therapy in infants with undiagnosed cholestasis. Histologic features in the liver may also have prognostic value in the patient with biliary atresia (BA). We assessed the relative value of histologic features in 227 liver needle biopsies in discriminating between BA and other cholestatic disorders in infants enrolled in a prospective Childhood Liver Disease Research Network (ChiLDReN) cohort study by correlating histology with clinical findings in infants with and without BA. In addition, we reviewed 316 liver biopsies from clinically proven BA cases and correlated histologic features with total serum bilirubin 6 months after hepatoportoenterostomy (the Kasai procedure, HPE) and transplant-free survival up to 6 years. Review pathologists were blinded to clinical information except age. Semiquantitative scoring of 26 discrete histologic features was based on consensus. Bile plugs in portal bile ducts/ductules, moderate to marked ductular reaction, and portal stromal edema had the largest odds ratio for predicting BA versus non-BA by logistic regression analysis. The diagnostic accuracy of the needle biopsy was estimated to be 90.1% (95% confidence interval [CI]: 85.2%, 94.9%), whereas sensitivity and specificity for a diagnosis of BA are 88.4% (95% CI: 81.4, 93.5) and 92.7% (95% CI: 84.8, 97.3), respectively. No histologic features were associated with an elevated serum bilirubin 6 months after HPE, although it (an elevated serum bilirubin) was associated with an older age at HPE. Higher stages of fibrosis, a ductal plate configuration, moderate to marked bile duct injury, an older age at HPE, and an elevated international normalized ratio were independently associated with a higher risk of transplantation.

Apurinic/apyrimidinic endonuclease (Ap endo) is a key DNA repair activity that confers radiation resistance in human cells. Here we examined the association between Ap endo activity and response to radiotherapy in pediatric ependymomas, tumors for which treatment options are limited and survival rates are only about 50%. We assayed Ap endo activity in 36 ependymomas and expression of Ape1/Ref-1, the predominant Ap endo activity in humans, in 44 tumors by immunostaining. Cox proportional hazards regression models were used to analyze the association of activity or expression with progression-free survival or with overall survival. Activity varied 13-fold and was not associated with tumor or patient characteristics. In univariate models with Ap endo activity entered as a continuous variable, the hazard ratio for progression increased by a factor of 2.18 for every 0.01 unit increase in activity (p ≤ 0.003) in 24 grade II ependymomas. Risk for death increased by a factor of 1.89 (p ≤ 0.02) in the same population. The fraction of Ape1/Ref-1 immunopositive cells varied widely within individual tumors and was not associated with either progression-free or with overall survival. Suppressing Ap endo activity in pediatric ependymoma cells significantly increased radiation sensitivity, suggesting that the association of activity with radiation response reflected, at least in part, repair of radiation-induced DNA lesions. Our data indicate that Ap endo activity is predictive of outcome following radiotherapy, and suggest that Ape1/Ref-1 promotes radiation resistance in pediatric ependymomas. Our findings support the use of inhibitors of Ap endo activity to overcome resistance.

X-linked intestinal pseudo-obstruction, a rare disorder caused by mutations in FLNA, the gene encoding the cytoskeletal protein filamin A, has been regarded as a hereditary enteric neuropathy largely on the basis of sparse and incomplete pathologic studies. Diffuse abnormal layering of small intestinal smooth muscle (DAL) is a rare malformation, which has only been described in 4 patients (all male, 3 in the same family) with intestinal pseudo-obstruction. We report DAL in 5 male patients (2 families) with intestinal pseudo-obstruction and mutations in FLNA. Light microscopic, ultrastructural, and immunohistochemical studies showed abnormal lamination of the small intestinal muscularis propria with associated absent or severely reduced FLNA immunoreactivity. Intestinal samples from the oldest patient in the series, a teenager, showed multinucleate myocytes in small and large intestine, along the submucosal surface of the muscularis propria. As neither DAL nor the pattern of myocyte multinucleation observed in our patients have been described outside the context of X-linked intestinal pseudo-obstruction, these histopathologic features may be specific for this hereditary disorder and suggest an underlying myopathic basis for dysmotility in affected patients.

Dobyns, William/0000-0002-7681-2844; VERLOES, Alain/0000-0003-4819-0264 WOS: 000273581000002 PubMed: 19574260 Objective To identify genetic causes of COACH syndrome Background COACH syndrome is a rare autosomal recessive disorder characterised by Cerebellar vermis hypoplasia, Oligophrenia (developmental delay/mental retardation), Ataxia, Coloboma, and Hepatic fibrosis. The vermis hypoplasia falls in a spectrum of mid-hindbrain malformation called the molar tooth sign (MTS), making COACH a Joubert syndrome related disorder (JSRD). Methods In a cohort of 251 families with JSRD, 26 subjects in 23 families met criteria for COACH syndrome, defined as JSRD plus clinically apparent liver disease. Diagnostic criteria for JSRD were clinical findings (intellectual impairment, hypotonia, ataxia) plus supportive brain imaging findings (MTS or cerebellar vermis hypoplasia). MKS3/TMEM67 was sequenced in all subjects for whom DNA was available. In COACH subjects without MKS3 mutations, CC2D2A, RPGRIP1L and CEP290 were also sequenced. Results 19/23 families (83%) with COACH syndrome carried MKS3 mutations, compared to 2/209 (1%) with JSRD but no liver disease. Two other families with COACH carried CC2D2A mutations, one family carried RPGRIP1L mutations, and one lacked mutations in MKS3, CC2D2A, RPGRIP1L and CEP290. Liver biopsies from three subjects, each with mutations in one of the three genes, revealed changes within the congenital hepatic fibrosis/ductal plate malformation spectrum. In JSRD with and without liver disease, MKS3 mutations account for 21/232 families (9%). Conclusions Mutations in MKS3 are responsible for the majority of COACH syndrome, with minor contributions from CC2D2A and RPGRIP1L; therefore, MKS3 should be the first gene tested in patients with JSRD plus liver disease and/or coloboma, followed by CC2D2A and RPGRIP1L. US National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [K23NS45832, K24HD46712, NCRR 5KL2RR025015, R01NS050375]; March of Dimes Endowment for Healthier BabiesMarch of Dimes; Ames Endowment Fund; Allan and Phyllis Treuer Endowed Chair This work was supported by the US National Institutes of Health (grants K23NS45832 to MAP, K24HD46712 to IAG, NCRR 5KL2RR025015 to DD, R01NS050375 to WBD), the March of Dimes Endowment for Healthier Babies (DD, MAP, and IAG), the Ames Endowment Fund at Seattle Children's Hospital (IAG), and the Allan and Phyllis Treuer Endowed Chair (PFC) at Seattle Children's Hospital.

The authors present the case of an 11-week-old girl in whom hydrocephalus developed secondary to intermittent obstruction of the third ventricle by a choroid plexus cyst. The patient presented to the emergency department at the authors' institution with a 1-day history of projectile vomiting, lethargy, and dysconjugate gaze. Hydrocephalus was confirmed on head CT. During hospitalization, the symptoms resolved with a decrease in ventricular size. One week later, the patient again presented with similar symptoms, and MR images with 3D-constructive interference in steady state sequences revealed that a cyst was blocking the third ventricle. The patient subsequently underwent endoscopic fenestration of the cyst with resolution of hydrocephalus and symptoms. The authors present a unique description of the diagnosis of intermittent obstructive hydrocephalus caused by a third ventricular region choroid plexus cyst in an infant.

BK nephropathy is a known cause of renal insufficiency in kidney transplant recipients. Activation of the polyoma virus may also occur in the native kidneys of non-renal allograft recipients. BK nephropathy has only been reported in a few patients after hematopoetic stem cell transplantation (HCT), most being adult patients, and the single reported pediatric case had evidence of hemorrhagic cystitis. The response to anti-viral therapy also seems to differ widely. Here, we describe two cases of BK nephropathy in the native kidneys of HCT recipients exposed to high levels of immunosuppression due to graft-versus-host-disease. Neither of our patients had any evidence of hemorrhagic cystitis. We present definitive renal pathology and detailed chronological evidence of the rising serum creatinine with simultaneous serum and urine BK PCR titers. In one of our cases, anti-viral therapy did not seem beneficial as documented by continued renal dysfunction and serum/urine BK PCR titers. Based on our report, intense immunosuppression in pediatric HCT recipients seems to be involved in the activation of BK virus and BK nephropathy should be suspected even in the absence of hematuria in HCT recipients with unexplained renal dysfunction.