Search

Nephronophthisis (NPH) is an autosomal-recessive ciliopathy representing one of the most frequent causes of kidney failure in childhood characterized by a broad clinical and genetic heterogeneity. Applied to one of the worldwide largest cohorts of patients with NPH, genetic analysis encompassing targeted and whole exome sequencing identified disease-causing variants in 600 patients from 496 families with a detection rate of 71%. Of 788 pathogenic variants, 40 known ciliopathy genes were identified. However, the majority of patients (53%) bore biallelic pathogenic variants in NPHP1. NPH-causing gene alterations affected all ciliary modules defined by structural and/or functional subdomains. Seventy six percent of these patients had progressed to kidney failure, of which 18% had an infantile form (under five years) and harbored variants affecting the Inversin compartment or intraflagellar transport complex A. Forty eight percent of patients showed a juvenile (5-15 years) and 34% a late-onset disease (over 15 years), the latter mostly carrying variants belonging to the Transition Zone module. Furthermore, while more than 85% of patients with an infantile form presented with extra-kidney manifestations, it only concerned half of juvenile and late onset cases. Eye involvement represented a predominant feature, followed by cerebellar hypoplasia and other brain abnormalities, liver and skeletal defects. The phenotypic variability was in a large part associated with mutation types, genes and corresponding ciliary modules with hypomorphic variants in ciliary genes playing a role in early steps of ciliogenesis associated with juvenile-to-late onset NPH forms. Thus, our data confirm a considerable proportion of late-onset NPH suggesting an underdiagnosis in adult chronic kidney disease.

Background Several cases of idiopathic nephrotic syndrome (INS) relapse following the administration of coronavirus disease 2019 (COVID-19) vaccines have recently been reported, raising questions about the potential relationship between the immune response to COVID-19 vaccination and INS pathogenesis. Methods We performed a retrospective multicentre survey describing the clinical and biological characteristics of patients presenting a relapse of INS after COVID-19 vaccination, with an assessment of outcome under treatment. Results We identified 25 patients (16 men and 9 women) presenting a relapse within 1 month of a COVID-19 vaccine injection. The glomerular disease was of childhood onset in half of the patients and most patients (21/25) had received at least one immunosuppressive drug in addition to steroids for frequently relapsing or steroid-dependent nephrotic syndrome (NS). All patients were in a stable condition at the time of injection and 11 had no specific treatment. In five patients, the last relapse was reported >5 years before vaccine injection. The Pfizer-BioNTech (BNT162b2) vaccine was used in 80% of the patients. In 18 cases, INS relapse occurred after the first injection, a mean of 17.5 days after vaccination. A second injection was nevertheless administered in 14 of these patients. Five relapses occurred after administration of the second dose and two relapses after the administration of the third dose. All but one of the patients received steroids as first-line treatment, with an additional immunosuppressive agent in nine cases. During follow-up, complete remission was achieved in 21 patients, within 1 month in 17 cases. Only one patient had not achieved at least partial remission after 3 months of follow-up. Conclusions This case series suggests that, in rare patients, COVID-19 vaccination may trigger INS relapse that is generally easy to control. These findings should encourage physicians to persuade their patients to complete the COVID-19 vaccination schedule.

International audience; Objective: Anakinra has been shown to be successful in preventing and treating cardiovascular lesions both in experimental murine models of Kawasaki disease (KD) and in several studies on intravenous immunoglobulin (IVIG)- and steroid-resistant patients with KD. This study was undertaken to determine the safety of blocking interleukin-1 in patients with IVIG-resistant KD.Methods: Sixteen patients were included in the present study. Patients with KD who were not responsive to 1 or more courses of 2 mg/kg of IVIG received anakinra by subcutaneous daily injections. Starting doses were 2 mg/kg of IVIG (4 mg/kg in patients who were age 38°C, indicative of a fever. Treatment duration was 14 days. The last visit was on day 45. Primary outcome was abatement of fever. Secondary measures included disease activity, coronary artery Z score, and C-reactive protein (CRP) levels.Results: Seventy-five percent of patients in the intention-to-treat group and 87.5% in the per-protocol group became afebrile within 48 hours of the last escalation dose of anakinra. Reduction of disease activity by 50% was indicated on 93.3% (95% confidence interval [95% CI] 68.1-99.8%) of physician evaluations and on 100% (95% CI 73.5-100%) of parent evaluations. CRP values normalized by day 30. At the initial screening, 12 of 16 patients had a maximum coronary artery Z score of >2, and 10 of 16 patients had a maximum Z score of >2.5. At day 45, 5 of 10 patients (50% [95% CI 18.7-81.3%]) and 6 of 12 patients (50% [95% CI 21.1-78.9%]) had achieved coronary artery Z scores of

International audience; Inappropriate stimulation or defective negative regulation of the type I interferon response can lead to autoinflammation. In genetically uncharacterized cases of the type I interferonopathy Aicardi-Goutières syndrome, we identified biallelic mutations in LSM11 and RNU7-1, which encode components of the replication-dependent histone pre-mRNA-processing complex. Mutations were associated with the misprocessing of canonical histone transcripts and a disturbance of linker histone stoichiometry. Additionally, we observed an altered distribution of nuclear cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) and enhanced interferon signaling mediated by the cGAS-stimulator of interferon genes (STING) pathway in patient-derived fibroblasts. Finally, we established that chromatin without linker histone stimulates cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) production in vitro more efficiently. We conclude that nuclear histones, as key constituents of chromatin, are essential in suppressing the immunogenicity of self-DNA.

Background Several models have been proposed to predict kidney graft failure in adult recipients but none in younger recipients. Our objective was to propose a dynamic prediction model for graft failure in young kidney transplant recipients. Methods We included 793 kidney transplant recipients waitlisted before the age of 18 years who received a first kidney transplantation before the age of 21 years in France in 2002–13 and survived >90 days with a functioning graft. We used a Cox model including baseline predictors only (sex, age at transplant, primary kidney disease, dialysis duration, donor type and age, human leucocyte antigen matching, cytomegalovirus serostatus, cold ischaemia time and delayed graft function) and two joint models also accounting for post-transplant estimated glomerular filtration rate (eGFR) trajectory. Predictive performances were evaluated using a cross-validated area under the curve (AUC) and R2 curves. Results When predicting the risk of graft failure from any time within the first 7 years after paediatric kidney transplantation, the predictions for the following 3 or 5 years were accurate and much better with the joint models than with the Cox model (AUC ranged from 0.83 to 0.91 for the joint models versus 0.56 to 0.64 for the Cox model). Conclusion Accounting for post-transplant eGFR trajectory strongly increased the accuracy of graft failure prediction in young kidney transplant recipients.

Background and objectives Therapeutic drug monitoring of mycophenolic acid can improve clinical outcome in organ transplantation and lupus, but data are scarce in idiopathic nephrotic syndrome. The aim of our study was to investigate whether mycophenolic acid pharmacokinetics are associated with disease control in children receiving mycophenolate mofetil for the treatment of steroid–dependent nephrotic syndrome. Design, setting, participants, & measurements This was a retrospective multicenter study including 95 children with steroid–dependent nephrotic syndrome treated with mycophenolate mofetil with or without steroids. Area under the concentration-time curve of mycophenolic acid was determined in all children on the basis of sampling times at 20, 60, and 180 minutes postdose, using Bayesian estimation. The association between a threshold value of the area under the concentration-time curve of mycophenolic acid and the relapse rate was assessed using a negative binomial model. Results In total, 140 areas under the concentration-time curve of mycophenolic acid were analyzed. The findings indicate individual dose adaptation in 53 patients (38%) to achieve an area under the concentration-time curve target of 30–60 mg·h/L. In a multivariable negative binomial model including sex, age at disease onset, time to start of mycophenolate mofetil, previous immunomodulatory treatment, and concomitant prednisone dose, a level of area under the concentration-time curve of mycophenolic acid >45 mg·h/L was significantly associated with a lower relapse rate (rate ratio, 0.65; 95% confidence interval, 0.46 to 0.89; P=0.01). Conclusions Therapeutic drug monitoring leading to individualized dosing may improve the efficacy of mycophenolate mofetil in steroid–dependent nephrotic syndrome. Additional prospective studies are warranted to determine the optimal target for area under the concentration-time curve of mycophenolic acid in this population.

Objective To document more fully the characteristics of chronic recurrent multifocal osteomyelitis (CRMO) in pediatric patients, to collect data on the outcomes and management of the disease, and to define prognostic factors. Methods One hundred seventy-eight patients were included (123 female patients and 55 male patients), with a mean ± SD age at diagnosis of 10.9 ± 2.9 years. Inclusion criteria were a diagnosis of CRMO, evidence of at least one lesion of osteitis confirmed by imaging, and development of the syndrome before age 18 years. Results Longitudinal clinical and imaging studies revealed that only 12 of 178 CRMO patients (7%) had unifocal lesions at the last medical visit. We were able to apply the clinical chronic nonbacterial osteomyelitis score to 110 of 178 patients (62%), which indicated that bone biopsy could have been avoided in 27 cases (25%). At the last medical visit, disease was in remission in only 73 of 171 patients (43%) (41% receiving therapy) after a mean ± SD of 47.9 ± 38.9 months; 44 of 171 patients (26%) experienced sequelae. Using cluster analysis, the CRMO cohort was separated into 3 homogeneous phenotypes (severe, mild, and intermediate). Patients with the severe phenotype had the worst prognosis. This group was entirely composed of male patients, most of whom had the multifocal form of CRMO and inflammatory syndrome. Patients with the mild phenotype had the best prognosis. This group was primarily composed of female patients with a unifocal form of CRMO and infrequent clavicle involvement and inflammatory syndrome. Patients with the intermediate phenotype had a good prognosis but greater reliance on treatment. This group primarily included female patients with multifocal lesions and inflammatory syndrome. Conclusion This is the largest CRMO cohort described in the literature to date. Clinical evolution and imaging investigations confirmed the multifocal pattern of the disease. Three distinct subgroups of CRMO patients were distinguished, with very different prognoses.

Background Henoch-Schonlein purpura, more recently renamed immunoglobulin A vasculitis (IgAV), is a systemic vasculitis characterized by IgA deposits. The current markers used to assess IgAV inaccurately evaluate the risk of nephritis occurrence and its long-term outcomes. The current study assessed biomarkers of nephritis outcomes. Methods This French multicentre prospective study enrolled 85 adult patients at the time of disease onset. Patients were assessed for clinical and biological parameters and re-examined after 1 year. Immunoglobulins, cytokines, IgA glycosylation, IgA complexes and neutrophil gelatinase-associated lipocalin (NGAL) concentrations were assessed in blood and urine. Results We identified 60 patients with IgAV-related nephritis (IgAV-N) and 25 patients without nephritis (IgAV-woN). At the time of inclusion (Day 1), the serum levels of galactose-deficient IgA1 (Gd-IgA1) and urinary concentrations of IgA, IgG, IgM, NGAL, interleukin (IL)-1β, IL-6, IL-8, IL-10, IgA-IgG and IgA-sCD89 complexes were higher in the IgAV-N patients than in the IgAV-woN patients (P

Rituximab (RTX) has recently showed promising results in the treatment of steroid-dependent idiopathic nephrotic syndrome (SDNS).This was a retrospective multicenter study of 18 children treated with RTX for SDNS, with a mean follow-up of 3.2 years. RTX was introduced because of side effects or relapses during therapy with immunosuppressive agents. The children received one to four infusions of RTX during the first course of treatment, and subsequent infusions were given due to CD19-cell recovery (CD19 1 %; 54 % of children) or relapse (41 %), as well as systematically (5 %).Treatment with RTX maintained sustained remission without relapse in 22 % of patients and increased the duration of remission in all other patients. The time between two successive relapses was 9 months in the absence of re-treatment and 24.5 months when infusions were performed at the time of CD19-cell recovery. At the last follow-up, 44.5 % of patients were free of oral drug therapy. Of those still receiving oral drugs, all doses had been decreased. No serious adverse events occurred.The results of this retrospective study confirm the efficacy and very good safety of RTX in the treatment of SDNS. The optimal therapeutic protocol seems to be a repeated single infusion at the time of CD19-cell recovery.

Resume Grâce a l’echographie prenatale, les reins kystiques sont, avec les uropathies obstructives, les anomalies renales les plus frequemment identifiees au cours de la vie fœtale. Ils recouvrent des entites tres differentes qu’il faut savoir reconnaitre etant donne les implications cliniques et genetiques qui en decoulent. Les plus frequentes sont les polykystoses renales autosomique dominante et recessive, suivies des anomalies kystiques liees aux mutations du gene TCF2/HNF1β . Des kystes renaux sont egalement observes dans d’autres maladies hereditaires ou syndromes polymalformatifs (sclerose tubereuse de Bourneville, syndrome de Meckel-Grubber, syndrome oro-facio-digital, etc.). Le diagnostic repose sur une analyse echographique et morphologique precise des anomalies renales, sur la recherche d’antecedents familiaux et de signes extra-renaux. Une meilleure classification de ces patients permettra a l’avenir de proposer un « suivi sur mesure ».

The aim of this study was to develop a population pharmacokinetic model of tacrolimus in pediatric kidney transplant patients, identify factors that explain variability, and determine dosage regimens. Pharmacokinetic samples were collected from 50 de novo pediatric kidney transplant patients (age 2-18 years) who were on tacrolimus treatment. Population pharmacokinetic analysis of tacrolimus was performed using NONMEM, and the impact of variables (demographic and clinical factors, and CYP3A4-A5, ABCB1, and ABCC2 polymorphisms) was tested. The pharmacokinetic data were described by a two-compartment model that incorporated first-order absorption and lag time. The apparent oral clearance (CL/F) was significantly related to body weight (allometric scaling); in addition, it was higher in patients with low hematocrit levels and lower in patients with CYP3A5*3/*3. The population pharmacokinetic-pharmacogenetic model developed in de novo pediatric kidney transplant patients demonstrated that, in children, tacrolimus dosage should be based on weight, hematocrit levels, and CYP3A5 polymorphism. Individualization of therapy will enable the optimization of tacrolimus exposure, with resultant beneficial effects on kidney function in the initial post-transplantation period.

BACKGROUND: Most data for treatment of dermatomyositis and juvenile dermatomyositis are from anecdotal, non-randomised case series. We aimed to compare, in a randomised trial, the efficacy and safety of prednisone alone with that of prednisone plus either methotrexate or ciclosporin in children with new-onset juvenile dermatomyositis.METHODS: We did a randomised trial at 54 centres in 22 countries. We enrolled patients aged 18 years or younger with new-onset juvenile dermatomyositis who had received no previous treatment and did not have cutaneous or gastrointestinal ulceration. We randomly allocated 139 patients via a computer-based system to prednisone alone or in combination with either ciclosporin or methotrexate. We did not mask patients or investigators to treatment assignments. Our primary outcomes were the proportion of patients achieving a juvenile dermatomyositis PRINTO 20 level of improvement (20% improvement in three of six core set variables at 6 months), time to clinical remission, and time to treatment failure. We compared the three treatment groups with the Kruskal-Wallis test and Friedman's test, and we analysed survival with Kaplan-Meier curves and the log-rank test. Analysis was by intention to treat. Here, we present results after at least 2 years of treatment (induction and maintenance phases). This trial is registered with ClinicalTrials.gov, number NCT00323960.FINDINGS: Between May 31, 2006, and Nov 12, 2010, 47 patients were randomly assigned prednisone alone, 46 were allocated prednisone plus ciclosporin, and 46 were randomised prednisone plus methotrexate. Median duration of follow-up was 35·5 months. At month 6, 24 (51%) of 47 patients assigned prednisone, 32 (70%) of 46 allocated prednisone plus ciclosporin, and 33 (72%) of 46 administered prednisone plus methotrexate achieved a juvenile dermatomyositis PRINTO 20 improvement (p=0·0228). Median time to clinical remission was 41·9 months in patients assigned prednisone plus methotrexate but was not observable in the other two treatment groups (2·45 fold [95% CI 1·2-5·0] increase with prednisone plus methotrexate; p=0·012). Median time to treatment failure was 16·7 months in patients allocated prednisone, 53·3 months in those assigned prednisone plus ciclosporin, but was not observable in patients randomised to prednisone plus methotrexate (1·95 fold [95% CI 1·20-3·15] increase with prednisone; p=0·009). Median time to prednisone discontinuation was 35·8 months with prednisone alone compared with 29·4-29·7 months in the combination groups (p=0·002). A significantly greater proportion of patients assigned prednisone plus ciclosporin had adverse events, affecting the skin and subcutaneous tissues, gastrointestinal system, and general disorders. Infections and infestations were significantly increased in patients assigned prednisone plus ciclosporin and prednisone plus methotrexate. No patients died during the study.INTERPRETATION: Combined treatment with prednisone and either ciclosporin or methotrexate was more effective than prednisone alone. The safety profile and steroid-sparing effect favoured the combination of prednisone plus methotrexate.FUNDING: Italian Agency of Drug Evaluation, Istituto Giannina Gaslini (Genoa, Italy), Myositis Association (USA).

OBJECTIVE Outcome of JDM is highly heterogeneous. Our objective was to determine clinical and muscle biopsy features associated with poor outcome and response to treatment. METHODS Clinical data and muscle biopsy were obtained from a monocentric cohort of 29 patients. Clinical subgroups were defined by latent class model analysis of initial and follow-up parameters. Myopathological features were analysed using validated scores. Capillary loss was determined on reconstructions of transversal sections and assessed in the different age groups to take into account variations of muscle capillarization during post-natal development. Regression models were used to identify initial predictors of therapeutic response. RESULTS Two distinct homogeneous subgroups of patients were identified according to clinical severity and pathological findings. The smallest group of patients (7/29) presented with severe JDM. Compared with the other group (22/29), patients had more severe muscle weakness at disease onset, low remission rate at 12 months, frequent subcutaneous limb oedema or gastrointestinal (GI) involvement and higher myopathological scores (capillary dropout, perifascicular necrosis/regeneration, fibres with internal myonuclei and fibrosis subscores). Relevance of capillary dropout to JDM severity was substantiated by age-based analysis, confirming its major role in JDM pathophysiology. Most of these manifestations could be related to vasculopathy (limb oedema, GI involvement, capillary dropout). Furthermore, Childhood Myositis Assessment Scale

Ciliopathies are a group of hereditary disorders associated with defects in cilia structure and function. The distal appendages (DAPs) of centrioles are involved in the docking and anchoring of the mother centriole to the cellular membrane during ciliogenesis. The molecular composition of DAPs was recently elucidated and mutations in two genes encoding DAPs components (CEP164/NPHP15, SCLT1) have been associated with human ciliopathies, namely nephronophthisis and orofaciodigital syndrome. To identify additional DAP components defective in ciliopathies, we independently performed targeted exon sequencing of 1,221 genes associated with cilia and 5 known DAP protein-encoding genes in 1,255 individuals with a nephronophthisis-related ciliopathy. We thereby detected biallelic mutations in a key component of DAP-encoding gene, CEP83, in seven families. All affected individuals had early-onset nephronophthisis and four out of eight displayed learning disability and/or hydrocephalus. Fibroblasts and tubular renal cells from affected individuals showed an altered DAP composition and ciliary defects. In summary, we have identified mutations in CEP83, another DAP-component-encoding gene, as a cause of infantile nephronophthisis associated with central nervous system abnormalities in half of the individuals.

Purpose Pediatric Kawasaki ocular involvement is dominated by bulbar conjunctival injection and mild, self-limited anterior uveitis. Posterior segment involvement is rare. Methods/Results Case report. Despite early efficient treatment including aspirin and intravenous immunoglobulins, a 12-year-old girl developed a severe bilateral global inflammatory ocular involvement including punctuated keratitis, retrodescemetic precipitates, anterior uveitis, vitritis, and bilateral optic disc swelling with papillitis. This is the first description of severe bilateral global inflammatory involvement of the eyes in Kawasaki disease (KD). Usually subclinical and self-limited, eye involvement in KD can lead to severe visual impairment. Conclusions Inflammation of both anterior and posterior segments does not seem to respond to KD-specific treatment and could justify a specific ophthalmologic therapeutic approach.

Cytophagic histiocytic panniculitis (CHP) is a rare panniculitis in childhood, associated either with nonmalignant conditions or with subcutaneous panniculitis-like T-cell lymphoma (SPTCL), and often also associated with macrophage activation syndrome (MAS). Discriminating between these 2 conditions is therapeutically important because nonmalignant CHP often improves under cyclosporine and prednisone, whereas most cases of SPLT may be best treated with more aggressive therapy. We report the cases of a 6-month-old boy and a 16-month-old girl who, after viral infection, developed multiple infiltrating skin nodules on the limbs and face, associated with MAS. Histopathologic findings for skin biopsy specimens revealed CHP associated with heavily cellular lobular panniculitis. Hemophagocytosis and immunohistochemical staining features were consistent with typical characteristics of in situ MAS in adipose tissue: the lymphocytes were mostly TCD8+ cells with an activated phenotype (human leukocyte antigen (HLA) -DR+) and expressed interferon-γ; CD68+ macrophages expressed tumor necrosis factor-α and interleukin-6. A monoclonal rearrangement of the T-cell receptor γ gene was present in skin tissue but not in peripheral blood or bone marrow lymphocytes. Cyclosporine A treatment resulted in the complete remission of cutaneous and systemic manifestations in both patients for 66 and 29 months, respectively. This report suggests that the diagnosis of a reactive T-cell lymphoproliferation should be the treatment of choice in young children with severe CHP, even if there is a SPTCL-like aspect with an in situ T-cell clonality. It also suggests that CSA is the optimal treatment of this condition and postulates the possible pathologic process underlying this efficacy.

The radiological assessment of CRMO is currently the subject of discussions and the recent use of whole-body MRI leads to discuss the respective roles of the imaging techniques.

Objective.To evaluate the safety and efficacy of rituximab (RTX) in juvenile dermatomyositis (JDM) in off-trial patients.Methods.We conducted a multicenter prospective study of patients with JDM included in the French Autoimmunity and Rituximab (AIR) registry.Results.Nine patients with severe JDM were studied. The main indication for RTX treatment was severe and/or refractory muscle involvement (7 patients), severe calcinosis (1 patient), or severe chronic abdominal pain associated with abdominal lipomatosis (1 patient). RTX was associated with corticosteroids, immunosuppressive drugs, and plasma exchange therapy in 9/9, 5/9, and 2/9 patients, respectively. Mild infections of the calcinosis sites occurred in 2 patients and an infusion-related event in 1. Complete clinical response was achieved in 3/6 patients treated with RTX for muscle involvement. In these responders steroid therapy was stopped or tapered to < 15% of the baseline dosage, with no relapse, with a followup ranging from 1.3 to 3 years. Calcinosis did not improve in the 6 affected patients.Conclusion.This small series suggests that rituximab may be effective for treating muscle and skin involvement in a small subset of children with severe JDM, and that its safety profile was satisfactory. Further studies are needed to identify predictive factors of response to RTX in patients with severe JDM.

Thanks to prenatal ultrasound scan, cystic kidneys, as well as obstructive uropathies, are the most frequent renal anomalies identified during pregnancy. They should be recognized because of genetic and clinical implications. The most frequent are autosomal dominant and recessive polycystic kidney diseases, followed by renal developmental anomalies linked to TCF2 gene. Renal cysts are also observed in other hereditary diseases or multiple malformation syndromes (tuberosis sclerosis, Meckel-Grubber syndrome, Oro-facial digital type 1 syndrome...). The diagnosis is based on a sonographic and morphological analysis of renal abnormalities, on the search for family histories and extra-renal manifestations. A better classification of these patients allows tailor-made follow-up and care improvement.

The objective was to develop a population pharmacokinetic pharmacogenetic model of mycophenolic acid following administration of mycophenolate mofetil (MMF) in de novo pediatric renal-transplant patients and identify factors that explain variability. The pharmacokinetic samples were collected from 89 de novo pediatric renal-transplant patients treated with MMF and studied during the first 60 postoperative days. All patients were genotyped for UGT1A8-A9, UGT2B7, and ABCC2. Population pharmacokinetic analysis was performed with the NONMEM and was validated using bootstrap visual predictive check. The pharmacokinetic data were best described by a 2-compartment model with Erlang distribution to describe the absorption phase. The covariate analysis identified body weight as an individual factor influencing central volume of distribution and concomitant immunosuppressive medication and identified body weight and UGT2B7 802C>T genotype as individual factors influencing apparent oral clearance (CL/F) of MMF. CL/F in cyclosporine-MMF-treated patients was 33% higher than in tacrolimus-MMF-treated patients. The CL/F was significantly lower in patients with UGT2B7 802 C/C genotype compared with patients with UGT2B7 802 C/T and 802T/T genotypes, and this effect was independent of concomitant immunosuppressive medication or body weight. The population pharmacokinetic-pharmaco-genetic model of mycophenolic acid was validated. Body weight, concomitant medication, and UGT2B7 genotype contribute significantly to the interindividual variability of MMF disposition in pediatric renal-transplant patients.

Background Ante/neonatal Bartter syndrome (BS) is a hereditary salt-losing tubulopathy due to mutations in genes encoding proteins involved in NaCl reabsorption in the thick ascending limb of Henle's loop. Our aim was to study the frequency, clinical characteristics and outcome of each genetic subtype. Methods Charts of 42 children with mutations in KCNJ1 (n = 19), SLC12A1 (n = 13) CLCNKB (n = 6) or BSND (n = 4) were retrospectively analysed. The median follow-up was 8.3 [0.4-18.0] years. Results We describe 24 new mutations: 10 in KCNJ1, 11 in SLC12A1 and 3 in CLCNKB. The onset of polyhydramnios, birth term, height and weight were similar for all groups; three patients had no history of polyhydramnios or premature birth and had CLCNKB mutations according to a less severe renal sodium wasting. Contrasting with these data, patients with CLCNKB had the lowest potassium (P = 0.006 versus KCNJ1 and P = 0.034 versus SLC12A1) and chloride plasma concentrations (P = 0.039 versus KCNJ1 and P = 0.024 versus SLC12A1) and the highest bicarbonataemia (P = 0.026 versus KCNJ1 and P = 0.014 versus SLC12A1). Deafness at diagnosis was constant in patients with BSND mutations; transient neonatal hyperkalaemia was present in two-thirds of the children with KCNJ1 mutations. Nephrocalcinosis was constant in KCNJ1 and SLC12A1 but not in BSND and CLCNKB patients. In most cases, water/electrolyte supplementation + indomethacin led to catch-up growth. Three patients developed chronic renal failure: one with KCNJ1 mutations during the second decade of age and two with CLCNKB and BSND mutations and without nephrocalcinosis during the first year of life. Conclusions We confirmed in a large cohort of ante/ neonatal BS that deafness, transient hyperkalaemia and severe hypokalaemic hypochloraemic alkalosis orientate molecular investigations to BSND, KCNJ1 and CLCNKB genes, respectively. Chronic renal failure is a rare event, associated in this cohort with three genotypes and not always associated with nephrocalcinosis.

Renal disease is rare in children with juvenile idiopathic arthritis, although a number of associated nephropathies have been described, including mesangial glomerulonephritis. We report the presence of mesangial glomerulonephritis, revealed by a nephrotic syndrome, in a paediatric patient with juvenile idiopathic arthritis. Short-term steroid treatment induced a rapid remission of the nephrotic syndrome, but the presence of anti-nuclear antibodies, 1:320 in a homogeneous pattern, irregular deposits of C1q in a renal biopsy, and a mother with episodes of cutaneous lupus suggested an uncertain renal evolution for this infant.

Background Juvenile dermatomyositis (JDM) is a rare and heterogeneous pediatric-onset idiopathic inflammatory myopathy. It is a heterogeneous disease which may be complicated by life-threatening complications. Identifying causes, clinical and biological manifestations and outcomes of such complications may be helpful for their better early management Objectives We aim to describe the causes of admission in paediatric intensive care unit (PICU), clinical and biological presentation and outcomes of JDM patients Methods Retrospective study of JDM patients admitted in two french paediatric PICUs from 2005 to 2013 among a cohort of 116 JDM patients followed during the same period. Results 11/116 JDM patients (9.5%) (8 girls and 3 boys, median age at diagnosis: 9.0±3.1 years) were admitted in ICUs because of digestive involvement (digestive perforation: 2 patients, digestive ulceration: 1 patient, severe ileus: 1 patient), cardiac involvement (severe bradycardia: 1 patient, cardiac arrest: 1 patient), respiratory failure resulting from hypoxemic pneumonia (1 patient), thrombotic microangiopathy (TMA) (2 patients), posterior reversible encephalopathy syndrome (PRES) related to cyclosporine use (1 patient), and anaphylactic shock after an infusion of Rituximab. At admission in ICU, patients presented with some manifestations which did not usually occur in typical JDM:) generalized edema (6/11 patients), hyponatremia (9/11 patients), hypoalbuminemia (9/11 patients) and thrombocytopenia (7/11 patients). Treatment consisted in corticosteroids (including pulses of methylprednisolone in 5 patients), intravenous immunoglobulin (7), plasmapheresis (7), infusions of rituximab (4) and cyclophosphamide (2). The mean duration of stay in PICU was 18.2 days. One patient died in ICU from pneumocystis carinii pneumonia. The remaining 10 patients are in complete or partial remission with a median duration of follow-up of 4,8 years. Conclusions Severe digestive vasculopathy, cardiac and pulmonary involvements, TMA and therapy-related adverse events were responsible for admissions in PICU in 9,5% of JDM patients in our cohorts. This report suggests that generalized edema, thrombocytopenia revealing TMA, hyponatremia and hypoalbuminemia are associated with severe JDM, and that pulses of methylprednisolone might favour digestive perforation in patients with preexisting gastrointestinal vasculitis. Outcomes was favourable in all the patients presenting with non-infectious severe complications. Disclosure of Interest None declared

Background The radiological assessment of CRMO is currently the subject of countless works and the recent use of whole-body MRI leads to discuss the respective roles of the various imaging techniques. Objectives This study provides a descriptive evaluation of imaging OCMR, its diagnostic management and a comparison between different techniques. Methods 178 CRMO patients were included (123 females and 55 males). The lesions detected by imaging (plain radiographs, isotopic bone scan and/or MRI) were collected by specifying the number, location (bone, proximal/distal and metaphyseal/epiphyseal/diaphyseal), character (lytic/sclerotic/mixed) and the signal MRI T1 and T2 (hypo/hyper). Results A total of 193 radiographic lesions were detected with the following distribution: tibia (n=44), the clavicle (n=34), the femur (n=23), the fibula (n=20) and pelvis (n=19). The lesions of the lower limbs accounted for 52% of the lesions. The lesions of the long bones were most often located in metaphyseal (58/76, 76%) and were lytic in 76/162 (47%) and sclerotic in 60/162 (37%). The isotopic bone scan detected 372 lesions localized to the pelvis (n=64), tibia (n=51), femur (n=44), clavicle (n=40) and vertebrae (n=29). The lesions of the pelvis were mainly in iliac bones (73%), proximal at clavicles (78%) and femur (57%), but distal at tibia (53%) and fibula (88%). Whatever the location of the long bones, the lesions were most often metaphyseal (65/92, 56%). MRI detected 515 lesions distributed as follows: pelvis (n=100), tibia (n=93) and femur (n=73). 51 vertebral lesions (10%) were detected in 36 patients. Most of them were localized at the thoracic level. The vast majority of lesions (98%) were hypo-T1 and hyper-T2. MRI showed metaphyso-epiphyseal and metaphyso-diaphyseal lesions usually undetectable in isotopic bone scan. Imaging has allowed confirming the multifocal pattern in 26/54 patients with clinical monofocal at the beginning of the disease. Of the remaining 28 patients with monofocal lesion at diagnosis, imaging contributed to confirm the multifocal pattern in 16 additional cases: a total of only 12 patients (7%) kept a pure monofocal evolution. In 15 patients, scintigraphy and whole-body MRI were performed at the same time (±3 months). Analysis of these 15 patients showed a higher sensitivity to detect lesions by MRI (6.7±3.1 vs 3.4±2.4, p=0.003) and better localization of lesions. Clinical chronic non bacterial osteitis (CNO) score was interpretable in 110 patients: the application of this score would have, in this cohort, to avoid 27/110 biopsies. Conclusions The study of imaging in this large CRMO French cohort confirms the interest of imaging to characterize multifocal involvement of CRMO and help prevent invasive procedures for diagnostic purposes. MRI confirms its sensitivity to detect more lesions including spinal and pelvis than isotopic bone scan. MRI provided a more detailed description of the location of the lesions. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.5337

Data regarding the safety and efficacy of treatment regimens for juvenile dermatomyositis (JDM) tends to be from anecdotal, small, uncontrolled, non-randomized case series.

Background Frequency of chronic recurrent multifocal osteomyelitis (CRMO), also known as nonbacterial osteomyelitis, seems to be underestimated and often leads to consequential residual impairments. Objectives The aim of this study was to collect the French cases of CRMO in order to precise clinical, biological, radiological and histological features. Methods In the absence of validated international diagnostic criteria, our inclusion criteria were: patient with at least one lesion of aseptic osteitis highlighted by imaging techniques (MRI or isotopic bone scan) and beginning before 18 years. Exclusion criteria were: onset after 18 years, other diagnosis (malignancy, infection, enthesitis related arthritis). Results 164 patients were included (115 females and 49 males): mean aged was 16.7±4.6 years and mean age at diagnosis was 11.1±2.9 years. The mean time between first symptom and diagnosis was 18±25.5 months. 46/164 (28%) patients had initial unifocal lesion In multifocal forms (118/164, 72%), the mean number of clinical locations was 3.4±1.7. 32/164 patients had fever and 109/164 had inflammatory syndrome. 21/164 patients had associated lesions (4 inflammatory bowel disease and 18 cutaneous lesions) and 47/164 had a familial history of psoriasis, spondyloarthritis, inflammatory bowel disease. Radiographs and/or bone scan and/or MRI confirmed multifocal involvement in 21/46 cases with initial clinical unifocal symptom. On the remaining 25 unifocal cases, clinical exam and imaging during evolution allowed to confirm that 12/25 patients had multifocal CRMO form: only 13/165 (8%) patients had persisting unifocal form. Bone biopsies were performed in 109 cases. The use of Jansson score, when it was applicable (n=88) before diagnosis, would have avoided 11 bone biopsies. NSAIDs were given as first line therapy to 159/164 patients. DMARDs were used in 28 patients, bisphosphonates in 16 and anti-TNFα in 13. Persisting unifocal patients were similar to multifocal except for a lesser use of DMARDs / biological treatments (BT = bisphosphonates and/or anti-TNFalpha). Comparison between CRMO patients needing or not BT showed differences for the gender (male: 52% vs 26%, p=0.01), multifocal form (96% vs 82%, p=0.04) and presence of sequelae[cd1] (43% vs 19%, p=0.009). Only 65 patients (40%) were considered in remission at the last visit after a mean follow-up of 50.3±39.7 months. 37/161 patients had sequelae including localized deformations (n=19) or vertebral fractures (n=6). Conclusions This cohort is the largest published CRMO cohort. Our results suggest that clinical evolution and repeated imaging technics (bone scan, MRI) could confirm the multifocal pattern of osteitis in initial unifocal form. Jansson score may also contribute to avoid 12% of bone biopsies. NSAIDs remained the main efficient first line treatment. Male gender and initial multifocal form are associated with the use of bisphosphonates and/or anti-TNFalpha. Disclosure of Interest None Declared