Lack of IL7Rα expression in T cells is a hallmark of T-cell immunodeficiency in Schimke immuno-osseous dysplasia (SIOD).

Schimke immuno-osseous dysplasia (SIOD) is an autosomal recessive, fatal childhood disorder associated with skeletal dysplasia, renal dysfunction, and T-cell immunodeficiency. This disease is linked to biallelic loss-of-function mutations of the SMARCAL1 gene. Although recurrent infection, due to T-cell deficiency, is a leading cause of morbidity and mortality, the etiology of the T-cell immunodeficiency is unclear. Here, we demonstrate that the T cells of SIOD patients have undetectable levels of protein and mRNA for the IL-7 receptor alpha chain (IL7Rα) and are unresponsive to stimulation with IL-7, indicating a loss of functional receptor. No pathogenic mutations were detected in the exons of IL7R in these patients; however, CpG sites in the IL7R promoter were hypermethylated in SIOD T cells. We propose therefore that the lack of IL7Rα expression, associated with hypermethylation of the IL7R promoter, in T cells and possibly their earlier progenitors, restricts T-cell development in SIOD patients.

Evaluation of tibial osteopathy occurrence in neurofibromatosis type 1 Italian patients.

Neurofibromatosis Type 1 (NF1) is a common autosomal dominant disorder characterized by high penetrance, widely variable expressivity and occurrence of specific skeletal changes such as tibial osteopathy (TO). We collected data on patients referred to the Italian Neurofibromatosis Study Group in order to compare clinical features between 49 NF1 patients with TO, and 98 age-matched NF1 patients without TO, and to determine whether the presence of TO is associated with a different risk of developing the typical NF1 complications. We assessed both groups for: age at diagnosis of NF1, gender distribution, family history, gender inheritance, presence of scoliosis, sphenoid wing osteopathy, other skeletal abnormalities, macrocrania, hydrocephalus, plexiform neurofibromas, tumors, optic pathway gliomas, T2H (high-signal intensity areas on T2 weighted brain MRI), epilepsy, headache, mental retardation, cardiovascular malformations, and Noonan phenotype. Patients of both groups were subdivided by gender and re-evaluated for these items. Statistical comparison was carried out between the two groups of patients for each feature. We collected data on type of treatment and on the clinical conditions of NF1-TO patients after follow-up. Patient's age at NF1 diagnosis was significantly younger in NF1-TO subjects compared with NF1 subjects without TO, and the incidence of T2H was significantly reduced in NF1-TO males compared with NF1 males without TO. The presence of TO does not imply that there is an increased risk of developing typical complications of NF1 (e.g., optic pathway glioma, plexiform neurofibroma, etc.), however, it does allow us to make an earlier diagnosis of NF1.

Differing urinary urea excretion among children with idiopathic hypercalciuria and/or hyperuricosuria.

OBJECTIVE: To estimate dietary protein intake in children with idiopathic hypercalciuria (HC) and/or hyperuricosuria (HU). PATIENTS AND METHODS: We compared the 24-h urinary excretion of urea, as a reflection of protein intake, in four age- and sex-matched groups, each comprising 56 consecutive children: (1) HC, (2) HU, (3) HC+HU and (4) control. RESULTS: Urinary urea excretion was significantly higher in HC, HU and HC+HU than in controls. HC and HU children had similar urea excretion. HC+HU children had urinary urea significantly higher than HC and HU, but urinary calcium similar to HC and urinary uric acid excretion similar to HU subjects. Urinary calcium was significantly (R(2)=0.21) correlated with urea excretion in HC children only, whereas urinary uric acid was significantly (R(2)=0.21) correlated with urinary urea in HU children only. No significant correlation between urinary urea and calcium or uric acid excretion was found in HC+HU patients although they had the highest urinary urea. A significant (p=0.004) interaction between urinary urea and sodium in increasing urinary calcium excretion resulted only in the HC group. CONCLUSION: The association of dietary protein excess with HC and/or HU is conditioned by an individual (genetic?) predisposition and may be produced by different mechanisms.

ROBO2 gene variants are associated with familial vesicoureteral reflux.

The SLIT2 receptor ROBO2 plays a key role in the formation of the ureteric bud, and its inactivation in mice leads to supernumerary ureteric bud development, lack of ureter remodeling, and improper insertion of the ureters into the bladder. Recently, two heterozygous ROBO2 missense mutations were identified in two families with primary vesicoureteral reflux occurring in combination with congenital anomalies of the kidney and urinary tract (VUR/CAKUT). This study investigated a possible causal role of ROBO2 gene variants in 95 unrelated patients with primary VUR (n = 78) or VUR/CAKUT. Eighty-two percent of all patients had a family history of genitourinary anomalies. Twenty-four ROBO2 gene variants were identified by direct sequencing of all 26 exons and the exon-intron boundaries. Of these, four led to amino acid substitutions: Gly328Ser, Asn515Ile, Asp766Gly, and Arg797Gln. When the families were examined, the missense variants co-segregated with VUR (three families) or VUR/CAKUT (one family). These variants were not found in 190 control subjects, and the affected amino acids have been conserved through evolution. In conclusion, a relatively high frequency of ROBO2 variants (5.1%) was found in familial cases; however, functional studies and validation in other cohorts are warranted.

A genome search for primary vesicoureteral reflux shows further evidence for genetic heterogeneity.

Vesicoureteral reflux (VUR) is the most common disease of the urinary tract in children. In order to identify gene(s) involved in this complex disorder, we performed a genome-wide search in a selected sample of 31 patients with primary VUR from eight families originating from southern Italy. Sixteen additional families with 41 patients were included in a second stage. Nonparametric, affected-only linkage analysis identified four genomic areas on chromosomes 1, 3, and 4 (p < 0.05); the best result corresponded to the D3S3681-D3S1569 interval on chromosome 3 (nonparametric linkage score, NPL = 2.75, p = 0.008). This region was then saturated with 26 additional markers, tested in the complete group of 72 patients from 24 families (NPL = 2.01, p = 0.01). We identified a genomic area on 3q22.2-23, where 26 patients from six multiplex families shared overlapping haplotypes. However, we did not find evidence for a common ancestral haplotype. The region on chromosome 1 was delimited to 1p36.2-34.3 (D1S228-D1S255, max. NPL = 1.70, p = 0.03), after additional fine typing. Furthermore, on chromosome 22q11.22-12.3, patients from a single family showed excess allele sharing (NPL = 3.35, p = 0.015). Only the chromosome 3q region has been previously reported in the single genome-wide screening available for primary VUR. Our results suggest the presence of several novel loci for primary VUR, giving further evidence for the genetic heterogeneity of this disorder.

Long-term evolution of renal damage associated with unilateral vesicoureteral reflux.

PURPOSE: We determined the long-term evolution of renal damage associated with vesicoureteral reflux. MATERIALS AND METHODS: We retrospectively selected 74 consecutive children with unilateral primary vesicoureteral reflux, ipsilateral renal differential uptake less than 45% at dimercapto-succinic acid scintigraphy performed 4 to 6 months after urinary tract infection (60 patients) or shortly after diagnosis of vesicoureteral reflux investigated for prenatal hydronephrosis (14), and normal ultrasound and scintigraphic imaging of the contralateral nonrefluxing kidney. Average patient age at diagnosis was 3 years. The outcome was assessed via dimercapto-succinic acid scan at 5 to 24 years (mean 8.9). RESULTS: In 65 patients (88%) variations of less than 5% in differential uptake were recorded. Three patients (4%) showed an increase of greater than 5% in differential uptake of the refluxing kidney. Six patients (8%) demonstrated a decrease of greater than 5%, of whom 3 had 1 and 3 had no febrile urinary tract infection during followup. A total of 18 patients had a differential uptake of 35% to 45% at the first visit, of whom 3 exhibited a decrease of 5.2% to 27% in differential uptake and had no history of febrile urinary tract infection. CONCLUSIONS: In most cases differential uptake of the unilaterally refluxing affected kidney remains stable from early childhood to puberty despite the increase in body mass, which necessitates increasing renal work. In some patients a significant decrease in differential uptake may be observed even in the absence of recurrent febrile urinary tract infections. A mild decrease in differential uptake (35% to 45%) at diagnosis does not exclude the possibility of a subsequent significant decrease, even in the absence of febrile urinary tract infection.

Atopy in childhood idiopathic nephrotic syndrome.

AIM: Aim of the study was to evaluate the immunoallergic pattern and their modulating serum cytokines in children with primary manifestation of nephrotic syndrome, in order to analyse the correlation with disease activity and the outcome of childhood NS. MATERIALS AND METHODS: We have evaluated 72 children: 58 steroid-sensitive and 14 steroid-resistant; 42 subjects were the healthy controls. In all were measured serum: T cell-subset, cytokines by Th-1, Th-2, total IgE levels and specific IgE antibodies. RESULTS: Of the 72 children investigated, 35 (48.6%) had either a history of atopy and/or elevated serum IgE; 14 of these children (40%) had clinical sign of an atopic disease (asthma, rhinitis, dermatitis) and 21 (60%) had elevated sIgE. The atopy was more frequent among SS than SRNS patients (52% versus 36%, p<0.05). The CD19 were significantly increased in nephrotic patients compared with controls. IL-4 levels were not different from those in normal control both in SS and SRNS patients, either in relapse than in remission. There was no correlation between the sIgE and IL-4 levels. Therefore, IL-5 and Il-13 levels were significantly higher in SSNS compared to controls, in both pre than posttreatment, and higher in atopic patients. Interestingly, IL-6 and IL-10 levels were significantly increased in SRNS pretreatment compared to posttreatment and controls and, only for IL-10, significantly higher in atopic patients. CONCLUSION: In our study, only 40% of atopic children had a positive allergic history and 51.4% of the nephrotic children had normal sIgE levels, both pre and posttreatment, indicating different aetiologies, as immune mechanisms, in the pathogenesis of NS. Therefore, specific IgE antibodies were not related to disease activity, suggesting that IgE production might be co-incident in childhood NS. However, the increased production of IL-5 and IL-13 in atopic SSNS may indicate that these cytokines are involved in the enhanced production of sIgE while IL-4 have a role as controlling cytokine.

Association of migraine-like headaches with Schimke immuno-osseous dysplasia.

Schimke immuno-osseous dysplasia (SIOD) is characterized by spondyloepiphyseal dysplasia, nephropathy, and T-cell deficiency. SIOD is caused by mutations in the putative chromatin remodeling protein SMARCAL1. We report an 8-year-old boy with SIOD and recurrent, severe, refractory migraine-like headaches. Through a retrospective questionnaire-based study, we found that refractory and severely disabling migraine-like headaches occur in nearly half of SIOD patients. We have also found that the vasodilator minoxidil provided symptomatic relief for one patient. We hypothesize that these headaches may arise from an intrinsic vascular, neuroimmune, or neurovascular defect resulting from loss of SMARCAL1 function.

Early cardiac morphologic and functional changes in neurofibromatosis type 1 hypertensives: an echocardiographic and tissue Doppler study.

BACKGROUND: Hypertension is frequently associated with neurofibromatosis type 1 (NF1), a common inherited disease that limits life expectancy. No data are available on cardiac damage in NF1 patients with hypertension. We evaluated cardiac function in NF1 patients with hypertension diagnosed by 24-h ambulatory blood pressure monitoring (ABPM), compared with normal children. METHODS: We studied 73 NF1 patients (41 boys; mean age 12 years) and 30 normal children comparable for age and sex, using standard 2D echocardiography, standard Doppler and Doppler tissue imaging (DTI). Twelve patients (16%) showed 24-h systolic blood pressure (SBP) or 24-h diastolic blood pressure (DBP) >95th percentile for age and sex. We divided the NF1 group into two subgroups: group A, patients with 24-h SBP and DBP 95th percentile for age and sex. RESULTS: Group B presented a thicker end-diastolic interventricular septum (p<0.0001), posterior wall (p=0.02), LVMI (p<0.001) and relative wall thickness (p<0.03) than group A and controls. Left atrial dimension in group B was also significantly larger. Examination by standard Doppler showed a deceleration and isovolumic relaxation time significantly prolonged in group B. DTI parameters were significantly higher in NF1 patients than controls. In group B, myocardial early diastolic (E(m)) and systolic (S(m)) velocities were significantly lower than group A. Myocardial early/late diastolic ratio (E(m)/A(m)) in NF1 patients was lower than controls and 19% of group A and 20% of group B showed an E(m)/A(m) ratio <1. No healthy subjects presented an E(m)/A(m) ratio <1. CONCLUSIONS: We demonstrated early cardiac morphologic and functional changes in young NF1 patients with hypertension. Because DTI directly studies cardiac muscle, it can detect changes induced by hypertension as well as those independent of blood pressure.

Long-term outcome of vesicoureteral reflux associated chronic renal failure in children. Data from the ItalKid Project.

PURPOSE: The nephropathy associated with vesicoureteral reflux (VUR) is one of the leading causes of chronic renal failure (CRF) in children. We describe the clinical course of the disease based on information available in the ItalKid Project database, and analyze the predictive value of baseline renal function, age at VUR diagnosis and urinary protein excretion in relation to the risk of progressive renal failure. MATERIALS AND METHODS: As of December 31, 2001 the registry included a total of 343 patients (261 males) with a diagnosis of primary VUR, which was the leading single cause of CRF, accounting for 25.4% of all patients with CRF. RESULTS: The estimated risk of end stage renal disease (ESRD) by age 20 years was 56%. The patients with a creatinine clearance (Ccr) of less than 40 ml per minute at baseline had an estimated 4-fold greater risk of ESRD developing in comparison with those whose Ccr was 40 to 75 ml per minute. No significant difference in probability of disease progression to ESRD was found between subjects diagnosed with VUR at age 6 months or less and those diagnosed later (older than 6 months). Furthermore, children with normal urinary protein excretion (a urinary protein [uPr]/urinary creatinine [uCr] ratio of less than 0.2 in 36 patients) and low grade proteinuria (uPr/uCr 0.2 to 0.8 in 34 patients) at baseline showed a significantly slower decrease in mean Ccr than those with moderate proteinuria (uPr/uCr greater than 0.8 in 34 patients). Hypertension and/or antihypertensive treatment (including antiprogressive drugs) were reported in 29.1% of patients. CONCLUSIONS: The results of the present study define the long-term risk of ESRD in a large population of children with CRF and VUR, and provide some critical information for identifying the prognosis.

Blood pressure and cardiovascular involvement in children with neurofibromatosis type1.

We evaluated blood pressure in a sample of patients with neurofibromatosis type 1 (NF1), using ambulatory blood pressure monitoring (ABPM), to determine whether ABPM, when compared with casual BP recordings, allowed the detection of a higher risk for hypertension. We also evaluated the correlation between BP and vascular abnormalities. We studied 69 NF1 patients (36 males and 33 females) with a mean age of 11+/-4 years, divided into group A, with 24-h mean systolic blood pressure (SBP) or diastolic blood pressure (DBP) <95th percentile, and group B, with mean SBP or DBP >95th percentile. Standard electrocardiography and M-mode, two-dimensional echocardiography were performed and all patients were in sinus rhythm. ABPM identified 11 hypertensive patients (16%); 5 had a mean SBP >95th percentile, 3 mean SBP-DBP >95th percentile, and 3 a mean DBP >95th percentile. Laboratory and other investigations to exclude secondary hypertension were normal. Cardiac abnormalities were found in 13 of the 69 patients (18.8%) with NF1. There were no significant clinical and cardiac differences between the normotensive and hypertensive group. Our data emphasize the importance of periodic ABPM in NF1 patients to diagnose hypertension early and avoid target organ damage and increased mortality.

Risk factors for poor renal prognosis in children with hemolytic uremic syndrome.

Many factors have been proposed as predictors of poor renal prognosis in children with hemolytic uremic syndrome (HUS), but their role is still controversial. Our aim was to detect the most reliable early predictors of poor renal prognosis to promptly identify children at major risk of bad outcome who could eventually benefit from early specific treatments, such as plasmapheresis. Prognostic factors identifiable at onset of HUS were evaluated by survival analysis and a proportional hazard model. These included age at onset, prodromal diarrhea (D), leukocyte count, central nervous system (CNS) involvement, and evidence of Shiga toxin-producing Escherichia coli (STEC) infection. Three hundred and eighty-seven HUS cases were reported; 276 were investigated for STEC infection and 189 (68%) proved positive. Age at onset, leukocyte count, and CNS involvement were not associated with the time to recovery. Absence of prodromal D and lack of evidence of STEC infection were independently associated with a poor renal prognosis; only 34% of patients D(-)STEC(- )recovered normal renal function compared with 65%-76% of D(+)STEC(+), D(+)STEC(-) and D(-)STEC(+ )patients. In conclusion, absence of both D and evidence of STEC infection are needed to identify patients with HUS and worst prognosis, while D(-) but STEC(+) patients have a significantly better prognosis.

Pelviureteral junction obstruction: correlation of renal cell apoptosis and differential renal function.

PURPOSE: We evaluated the relationship between renal biopsy changes and preoperative and postoperative renal scans in 29 male and 14 female infants with prenatal severe hydronephrosis and unilateral ureteropelvic junction obstruction. We also verified on immunohistochemical studies glomerular changes, degeneration of the epithelium of the proximal tubules, interstitial fibrosis and inflammation and apoptotic nuclei. MATERIALS AND METHODS: In the children, all with prenatal diagnosis of hydronephrosis, ureteropelvic junction obstruction was diagnosed with 99mtechnetium mercaptoacetyltriglycine renal scan performed in all patients at ages 4 to 6 weeks to establish baseline differential renal function. All patients underwent renal biopsies at the time of pyeloplasty. The biopsy samples were examined with histological and immunohistochemical methods for antigens associated with apoptosis, such as clusterin, CD95, TDAG51 and bcl-2. Renograms were performed 3 months after surgical repair. RESULTS: The male-to-female ratio was 2.1:1. There was no difference between males and females in regard to baseline differential renal function of the affected kidney. All biopsy samples confirmed degeneration of the epithelium of the proximal tubules, interstitial focal fibrosis was found in 4 samples, mild chronic inflammation with lymphoid aggregates in 4 and focal Bowman's space dilatation in 1. No specimen demonstrated apoptotic nuclei as confirmed by immunohistochemical study which showed the presence of bcl-2 and absence of CD95, TDAG51 and clusterin, probably because there was no dysplasia in the samples examined. CONCLUSIONS: These results indicate absence of apoptosis in the kidney with preoperative uptake less than 40% and minimal histological changes.

Reflux nephropathy and hypertension: correlation with the progression of renal damage.

The aim of this study was to evaluate the relationship between blood pressure (BP), measured with ambulatory blood pressure monitoring (ABPM), and the progression of renal damage in 100 (70 females, 30 males) normotensive children with reflux nephropathy (RN). The patients, mean age of 13.5+/-5 years and almost 5 years of follow-up, were divided according to degree of RN into group A (I/II) and group B (III/IV). For each subject, 24-h systolic and diastolic BP (SBP-DBP), load (percentage of BP readings that exceeded the age- and sex-specific 95th percentile), and biochemical parameters were recorded. There was no significant difference in casual BP between the groups. The mean 24-h SBP-DBP and load were significantly higher in group B than A. There was a significant difference in creatinine (Cr) levels between the groups, and Cr correlated with BP in both groups. In group B, microalbuminuria correlated with ambulatory BP, and plasma renin activity failed to decrease with chronological age. Elevated load was shown in 8 of 50 patients in group A and in 21 of 50 in group B. In 3 of 12 patients of group B, with increased load BP, left ventricular geometry, by integrated backscatter, was abnormal. ABPM was useful in selected children at risk of hypertension.

Non-allelic heterogeneity in familial unilateral renal adysplasia.

We report three families with dominant unilateral renal adysplasia without vesico-ureteral reflux. No dysmorphia or anomalies were evident in the reproductive system. Ophthalmological examination excluded the presence of optic nerve coloboma or other ocular anomalies. No mutations were detected in the EMX(2) and in PAX(2) genes of affected members. Other homeobox genes could be responsible for this anomaly in these three families.

The heart in neurofibromatosis type 1: an echocardiographic study.

BACKGROUND: Comprehensive data are unavailable for cardiac abnormalities in patients with neurofibromatosis type 1 (NF1). The goal of this study was to evaluate the prevalence of cardiovascular abnormalities with echocardiography with color Doppler scan (ECHO) in a large, consecutive series of patients with NF1. METHODS: We studied 48 patients with NF1 (mean age, 10 years). Thirty healthy subjects comparable for age and sex served as the control group. All ECHO studies were performed by the same cardiologist and reviewed by a second cardiologist blinded to the physical findings of the subjects. RESULTS: Cardiac abnormalities were found in 13 of the 48 young patients (27%). A secundum atrial septal defect with a left to right shunt was found in 2 children. ECHO evidence of mild left pulmonary artery stenosis was found in 1 participant. A moderate coarctation of the thoracic aorta was found in 1 patient. ECHO criteria for mitral valve prolapse and evidence of trivial mitral regurgitation with myxomatous mitral valve was present in 1 case. Mild mitral regurgitation was found in 2 patients. A regurgitant mild flow signal was detected from the aortic valve in 2 subjects. Atrial septal aneurysm was found in 2 patients without patent foramen ovale. Two patients had septal to posterior left ventricular free wall ratio greater than 1.5, suggesting hypertrophic cardiomyopathy. CONCLUSION: This is the first attempt to evaluate the prevalence of cardiovascular abnormalities in patients with NF1 with ECHO. The study's most striking finding is the high prevalence of cardiovascular abnormalities. Congenital lesions have potential long-term hemodynamic consequences that justify an early diagnosis. Thus, a cardiologic assessment at regular intervals, including ECHO study, is mandatory for patients with NF1.

T-lymphocyte populations and cytokines in childhood nephrotic syndrome.

We investigated lymphocyte subpopulations and the production of cytokines by T helper cell subtype 1 (Th1), Th2, and monocytes/macrophages (tumor necrosis factor-alpha [TNF-alpha]) in peripheral-blood mononuclear cells of 18 children with steroid-sensitive (SS) nephrotic syndrome (NS) and 10 children with steroid-resistant (SR) NS. Mean age was 10.9 +/- 5.7 years, with a mean follow-up before the study of 6 +/- 5 years. To evaluate the possible relationship between cytokine levels and response to treatment, patients with SS and SR NS were assessed during relapse/marked proteinuria (group A), total/partial remission (group B), and off treatment (group C). In children with SS and SR NS, we found no significant difference in CD3 counts compared with controls. The proportion of CD4 cells decreased significantly in relapse and off therapy compared with controls in children with SS NS, whereas in those with SR NS, there was a concomitant reduction in all groups. B-Lymphocyte counts were significantly increased in either group versus controls. In SR NS, CD8 and natural killer cell levels increased during relapse versus controls. The CD4+/CD8+ ratio was reduced to the same degree in those with SS and SR NS. In patients with SR NS, we observed increased levels of soluble interleukin-2 (IL-2) receptor (sIL-2R) from corresponding control values (P < 0.01). A significant increase in TNF-alpha levels was found in patients with SS and SR NS versus controls. High levels of IL-2, sIL-2R, and interferon-gamma during relapse in patients with SS NS give further evidence for a Th1 pattern that might be involved in the pathogenesis of NS, and monitoring the Th1/Th2 balance would be useful in evaluating the response to therapy.

Mutant chromatin remodeling protein SMARCAL1 causes Schimke immuno-osseous dysplasia.

Schimke immuno-osseous dysplasia (SIOD, MIM 242900) is an autosomal-recessive pleiotropic disorder with the diagnostic features of spondyloepiphyseal dysplasia, renal dysfunction and T-cell immunodeficiency. Using genome-wide linkage mapping and a positional candidate approach, we determined that mutations in SMARCAL1 (SWI/SNF2-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1), are responsible for SIOD. Through analysis of data from persons with SIOD in 26 unrelated families, we observed that affected individuals from 13 of 23 families with severe disease had two alleles with nonsense, frameshift or splicing mutations, whereas affected individuals from 3 of 3 families with milder disease had a missense mutation on each allele. These observations indicate that some missense mutations allow retention of partial SMARCAL1 function and thus cause milder disease.