Etienne Bérard

Recombinant human growth hormone treatment of children on hemodialysis

Abstract. Forty-two children, aged 2–21.5 years on hemodialysis with a height below –2.0 standard deviation score (SDS) for age, were selected to receive recombinant human growth hormone (rhGH) therapy at 17 French centers. Of the 42 children, 36 were prepubertal and 8 were in early puberty (testicular volume between 4 and 8 ml for boys, breast development B2 or B3 in girls). All received 1 IU/kg per week by daily subcutaneous injection for 1–5 years. The year before rhGH therapy served as a control period. During the 1st year of treatment, mean growth velocity increased from 3.5 to 7.0 cm/year (P <0.0001) and was always over 2.5 cm/year. This velocity allowed a catch-up growth of +0.5 height SDS. Neither weight nor the body mass index varied compared with the pretreatment year. No change was observed in urea, creatinine, or glucose tolerance. The mean increment in bone age was 0.9 years. The mean growth velocity decreased over subsequent years (P <0.0001), but remained higher than the prestudy velocity. A significant negative correlation was observed during the 1st year between the increase in growth velocity and the prestudy velocity (P <0.0001), with the least gain in patients who had the best spontaneous velocity. Pubertal status had no influence on response to rhGH. No significant side effects were observed during the 103 treatment-years. Five patients developed secondary hyperparathyroidism and 1 suffered from acute pancreatitis, but the relationship with rhGH therapy remains uncertain. rhGH therapy appears indicated for children on hemodialysis, even though the potential benefits appear somewhat lower for those with a spontaneous growth velocity over 6 cm/year.

Renovascular hypertension and vascular anomalies in Alagille syndrome

Abstract. Alagille syndrome (AS) is characterized by the association of at least three of the following five abnormalities: chronic cholestasis, peripheral pulmonary artery stenosis, vertebral arch defects, embryotoxon, and typical facies. In addition to urological abnormalities, tubulointerstitial nephritis, renal tubular acidosis, and mesangiolipidosis have been noted in AS. The usual manifestations of such renal pathologies rarely include hypertension. We report five patients with at least four of the five major features of AS who developed secondary hypertension of renovascular origin 3.5–28 years after the initial diagnosis of AS. Angiography demonstrated uni- or bilateral renal artery stenosis and various other abnormalities of the main arteries in all five patients: aorta (3 cases), celiac artery (4 cases), superior mesenteric artery (1 case), subclavian artery (1 case). Our findings underscore the value of arterial blood pressure monitoring in patients with AS. If hypertension occurs, a renovascular origin should be sought. The diffuse vascular abnormalities which appeared to be a feature of AS in these patients should prompt larger studies of vascular abnormalities in AS.

Respiratory chain deficiency presenting as congenital nephrotic syndrome

Nephrotic syndrome (NS) in infancy includes NS of Finnish type (mutation of the nephrin gene), diffuse mesangial sclerosis (idiopathic or linked to WT1 mutation), idiopathic NS, most often steroid resistant, and NS related to infections during pregnancy (virus, syphilis, toxoplasmosis). Later in life, NS has a large variety of etiologies. It has been described in association with neuromuscular symptoms, deafness, and diabetes in a few children and adults with respiratory chain (RC) disorders. To date, however, NS has never been observed in neonates with RC disorders. Here, we report RC deficiency in one infant with certain congenital NS and two siblings with acute neonatal cardiac and renal disease with probable NS. Although clinical and histopathological presentations were initially close to congenital NS of Finnish type, clinical outcome was atypical and nephrin mutation was excluded. Mitochondrial RC complex II+V deficiency was identified in the three patients. Based on these observations, we suggest that RC disorders should be considered in patients with congenital NS.

Pediatric en bloc kidney transplantation into pediatric recipients: the French experience.

Afanetti M, Niaudet P, Niel O, Saint Faust M, Cochat P, Berard E. Pediatric en bloc kidney transplantation into pediatric recipients: The French experience. 
Pediatr Transplantation 2012: 16: 183–186.

Cystinosin is a melanosomal protein that regulates melanin synthesis

Cystinosis is a rare autosomal recessive disease characterized by cystine crystal accumulation leading to multiorgan dysfunctions and caused by mutation in CTNS. CTNS encodes cystinosin, a cystine/H+ symporter that exports cystine out of the lysosomes. Patients with cystinosis frequently exhibit blond hair and fair complexion, suggesting an alteration in melanogenesis. However, the pigmentation singularities of these patients have not been studied, and the role of cystinosin in melanogenesis has remained unknown. In our study, a clinical evaluation of 27 patients with cystinosis showed that 44% had a cutaneous pigmentation dilution compared to their relatives. Analysis of the hair melanin content in these patients by HPLC demonstrated a 50% decrease in eumelanin (4360 vs. 9360 ng/mg), and a 2‐fold increase in pheomelanin (53 vs. 20 ng/mg), the yellow/red pigments. Cystinosin‐deficient mice also showed a 4‐fold increase in hair pheomelanin content. In vitro studies showed that cystinosin was located at melanosomes. CTNS silencing led to a 75% reduction of melanin synthesis that was caused by a degradation of tyrosinase by lysosomal proteases. Our results objectify the pigmentation defect in patients with cystinosis. We also identify the role of CTNS in melanogenesis and add a new gene to the list of the genes involved in the control of skin and hair pigmentation.—Chiaverini, C., Sillard, L., Flori, E., Ito, S., Briganti, S., Wakamatsu, K., Fontas, E., Berard, E., Cailliez, M., Cochat, P., Foulard, M., Guest, G., Niaudet, P., Picardo, M., Bernard, F.‐X., Antignac, C., Ortonne, J. P., Ballotti, R. Cystinosin is a melanosomal protein that regulates melanin synthesis. FASEB J. 26, 3779–3789 (2012). www.fasebj.org

Mutation Update of the CLCN5 Gene Responsible for Dent Disease 1

Dent disease is a rare X‐linked tubulopathy characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis and/or nephrolithiasis, progressive renal failure, and variable manifestations of other proximal tubule dysfunctions. It often progresses over a few decades to chronic renal insufficiency, and therefore molecular characterization is important to allow appropriate genetic counseling. Two genetic subtypes have been described to date: Dent disease 1 is caused by mutations of the CLCN5 gene, coding for the chloride/proton exchanger ClC‐5; and Dent disease 2 by mutations of the OCRL gene, coding for the inositol polyphosphate 5‐phosphatase OCRL‐1. Herein, we review previously reported mutations (n = 192) and their associated phenotype in 377 male patients with Dent disease 1 and describe phenotype and novel (n = 42) and recurrent mutations (n = 24) in a large cohort of 117 Dent disease 1 patients belonging to 90 families. The novel missense and in‐frame mutations described were mapped onto a three‐dimensional homology model of the ClC‐5 protein. This analysis suggests that these mutations affect the dimerization process, helix stability, or transport. The phenotype of our cohort patients supports and extends the phenotype that has been reported in smaller studies.

Fluconazole therapy for Candida albicans urinary tract infections in infants

Abstract. Candiduria is rare in newborns and infants, occurring most often in patients with risk factors. When associated with a candidal bezoar in the urinary tract, candiduria is usually treated by systemic amphotericin B and flucytosine plus local irrigation with amphotericin B. We describe the successful treatment of five newborns with a urinary tract infection, on major urological malformations, due to Candida albicans (including three with a candidal bezoar) by fluconazole alone. No adverse effects or recurrences were observed. Fluconazole therapy permits early discharge from the hospital and seems suitable for infants and newborns with a C. albicans urinary tract infection.

Nephrocalcinosis and Prematurity: Importance of Urate and Oxalate Excretion

Nephrocalcinosis was described in preterm infants by several authors who tried to determine its association with hypercalciuria and furosemide therapy. We evaluated these potential mechanisms along with other lithogenic factors not previously studied in 10 premature babies. Hypercalciuria was an inconsistent finding like in other reports; elevated uric acid excretion and hyperoxaluria were observed in 5 and 6 cases, respectively. The aminocid excretion was normal in all infants. Our data suggest that in addition to hypercalciuria, other lithogenic factors may play a role in the pathophysiology of nephrocalcinosis of premature infants.

In vivo reflectance confocal microscopy of the skin: A noninvasive means of assessing body cystine accumulation in infantile cystinosis

BACKGROUND Patients with infantile nephropathic cystinosis have progressive accumulation of cystine in tissues leading to delayed extrarenal complications. No simple tool is available to evaluate the level of body cystine accumulation. OBJECTIVE We sought to determine the value of in vivo reflectance confocal microscopy of the skin in patients with infantile nephrogenic cystinosis. METHODS Nine patients and control subjects were recruited for this study. Images were acquired by means of a near-infrared reflectance confocal laser scanning microscope. RESULTS Scattered bright particles within the papillary dermis were observed in all patients but not in control subjects. The density of particles ranged from numerous (+++) to very few (+/-) and their distribution was heterogeneous. Electron microscopy confirmed that these particles corresponded to cystine crystal deposits within dermal fibroblasts. The density of cystine crystals within the dermis was greater in older patients, in patients with a high leukocyte cystine concentration, and with delayed cysteamine therapy. There was no correlation between the density of cystine deposits and renal disease or hypopigmentation but high levels of deposition occurred in association with extrarenal manifestations. LIMITATIONS This is a preliminary study on a small sample of patients. Repeated examination and longer follow-up is necessary. CONCLUSION In vivo reflectance confocal microscopy of the skin appears to be a noninvasive means of assessing body cystine accumulation in infantile cystinosis and could be used as a complementary marker of treatment response in addition to leukocyte cystine measurement.

Pharmacokinetics of mycophenolate mofetil in children with lupus and clinical findings in favour of therapeutic drug monitoring.

AIMS The use of mycophenolate mofetil (MMF) in children with systemic lupus erythematosus (SLE) is increasing. However, the clinical benefit of its monitoring has been scarcely studied, and little is known about its pharmacokinetics in this context. The objectives of the present study were: (i) to describe mycophenolic acid (MPA, the active moiety of MMF) pharmacokinetics, (ii) to develop a Bayesian estimator (BE) allowing the determination AUC (area under the curve) from a limited number of blood samples and (iii) to explore the relationships between exposure indices to MPA and the clinical status in children with SLE. METHODS This was a retrospective study including 36 children with SLE, extracted from the expert system ISBA, for whom full- pharmacokinetic profiles of MPA were collected together with clinical data. A pharmacokinetic model and a BE were developed using an iterative two stage Bayesian approach. ROC curve analyses and logistic regressions were used to investigate the association of exposure and active disease. RESULTS A pharmacokinetic model and a BE were developed that allowed good AUC estimation performance (bias ± SD = -0.02 ± 0.15). ROC curve analyses showed that AUC/dose <0.06 and AUC <4 mg l(-1)  h were associated with a good sensitivity and specificity for active disease (78%/94% and 94%/56%, respectively). When introduced in a logistic regression model, AUC <44 mg l(-1)  h and AUC/dose <0.06 were associated with an increased risk of active disease (OR = 21.2, 95% CI 2.3, 196.1, P = 0.007 and OR = 59.5, 95% CI 5.9, 588.2, P = 0.0005 respectively]. CONCLUSIONS The developed pharmacokinetic BE could be used to test prospectively the interest of MPA monitoring for limiting relapse of the disease or its progression.