Ahmed M. Badr

Clinical characterization and NPHP1 mutations in nephronophthisis and associated ciliopathies: A single center experience

Nephronophthisis (NPHP) is a recessive disorder of the kidney that is the leading genetic cause of end-stage renal failure in children. Egypt is a country with a high rate of consanguineous marriages; yet, only a few studies have investigated the clinical and molecular characteristics of NPHP and related ciliopathies in the Egyptian population. We studied 20 children, from 17 independent families, fulfilling the clinical and the ultrasonographic criteria of NPHP. Analysis for a homozygous deletion of the NPHP1 gene was performed by polymerase chain reaction on the genomic DNA of all patients. Patients were best categorized as 75% juvenile NPHP, 5% infantile NPHP, and 20% Joubert syndrome-related disorders (JSRD). The mean age at diagnosis was 87.5 + 45.4 months, which was significantly late as compared with the age at onset of symptoms, 43.8 ± 29.7 months (P <0.01). Homozygous NPHP1 deletions were detected in six patients from five of 17 (29.4%) studied families. Our study demonstrates the clinical phenotype of NPHP and related disorders in Egyptian children. Also, we report that homozygous NPHP1 deletions account for 29.4% of NPHP in the studied families in this cohort, thereby confirming the diagnosis of type-1 NPHP. Moreover, our findings confirm that NPHP1 deletions can indeed be responsible for JSRD.

Homozygous NPHP1 deletions in Egyptian children with nephronophthisis including an infantile onset patient

Sirs, Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease that constitutes the most frequent genetic cause for end-stage renal disease (ESRD) in the first three decades of life. Homozygous deletions in the NPHP1 gene account for approximately 21% of all NPHP cases, whereas the other genes contribute less than 3% each. Interestingly, positional cloning of the nine genes (NPHP 1 through 9) and functional characterization of their encoded proteins (nephrocystins) have contributed to a unifying theory that defines cystic kidney diseases as “ciliopathies” [1]. Since there are no clinical or molecular data about NPHP in Egyptian children, we investigated the prevalence of homozygous NPHP1 deletion among a cohort of children with presumptive diagnosis of NPHP at Center of Pediatric Nephrology & Transplantation (CPNT), Cairo University. We studied 20 children, from 17 independent families, fulfilling the clinical and the ultrasonographic criteria of NPHP. All patients had full ophthalmologic examination, brain MRI was carried out in children with neurological involvement. Analysis for a homozygous deletion of the NPHP1 gene was performed by multiplex polymerase chain reaction (PCR) approach on genomic DNA of patients described earlier [2]. Sex distribution among affected patients showed a slight preponderance of females, with a ratio of 1.2:1 (11 females and 9 males). Seventy five percent of our study patients were the products of consanguineous marriages, the percentage of affected siblings was strikingly high 65% (13/20 patients) and 40% (8/20 patients) had a history of sibling death due to a similar condition. Fifteen of 20 patients (75%) presented with signs of ESRD. All the patients suffered from anemia and growth retardation when they first came to medical attention. Nineteen of 20 patients (95%) had a history typical of nephronophthisis, with symptoms of polydipsia, polyuria, and secondary enuresis. Four of 20 patients (20%) were hypertensive with elevated blood pressure above the 95th percentile for age, gender, and height. Clinically, study patients were best categorized as: 13/20 (65%) patients with isolated juvenile NPHP, 3/20 (15%) patients as infantile NPHP, while the remaining 4/20 (20%) patients had extrarenal associations (molar tooth sign on brain MRI, ataxia, mental retardation, retinal dystrophy, oculomotor apraxia, and facial dysmorphy) hence were clinically categorized as Joubert Syndrome Related Disorder (JSRD). The mean age at diagnosis 87.5 + 45.4 months was significantly late as compared to the age of onset of symptoms 43.8 ± 29.7 months (P <0.01). Homozygous deletions in the NPHP1 gene were identified in 6 patients from 5 independent families out of the 17 studied families (29.4%), thereby confirming the diagnosis of type 1 nephronophthisis (Fig. 1). This does not seem to differ from reported figures in Western countries. Five patients had isolated NPHP whereas the sixth patient was among the JSRD group with the distinct MTS detected in his brain MRI images, ataxia, retinitis pigmentosa and dysmorphic facies. This confirms that NPHP1 deletions can indeed be responsible for JSRD as previously reported [3]. Figure 1 Screening for homozygous NPHP1 deletions. 20 patients (lane 1–20) from 17 independent families were analyzed using a multiplex PCR approach amplifying 5 different markers. Two control markers (a, e) and 3 NPHP1 exon markers [arrow “d” ... Moreover we report one patient with the homozygous NPHP1 deletion presenting with an infantile onset phenotype. In the literature, Infantile NPHP frequently caused by mutations in the NPHP2/inversin gene differs from the other types of NPHP in the early age of onset of ESRD usually <5 years in all reported cases, whereas the median age of ESRD in juvenile NPHP (NPHP type 1 or type 4) is about 13 years [4]. Renal cortical microcysts is another criterion where detailed analysis of a murine model of NPHP2/inversin demonstrates cystic dilatation of Bowman’s capsule, proximal tubule, thick ascending limb and collecting duct [5]. Although homozygous NPHP1 deletions is the most frequent NPHP1 mutation known, nevertheless, in more than 6% of all NPHP1 cases the underlying mutation has been found to be a heterozygous deletion combined with a single point mutation [2]. As for the patients with no homozygous NPHP1 deletion we will investigate for heterozygous deletions in a future study. Further analysis of all other NPHP loci for potential homozygosity in consanguineous families and sequencing all exons of NPHP genes located within regions of significant homozygosity is crucial to identify the underlying genetic defect. Our infantile NPHP patient showed most of the clinical and histopathological features of NPHP type 2 previously reported in the literature [4]: (1) the characteristic cortical cysts in a normal sized hyperechogenic kidneys on renal sonogram, (2) distinct renal microcysts in the kidney histopathological examination, (3) clinical manifestations started in the first year of life and progressed to ESRD at the age of 32 months. In conclusion, homozygous deletions in the NPHP1 gene do not seem to differ in Egypt from reported figures in Western countries. Most likely this is the first report of a homozygous NPHP1 deletion in an infantile onset NPHP patient.

Pulmonary hypertension and cardiac hypertrophy in children recipients of orthotopic living related liver transplantation

Graphical abstract

Neonatal Candiduria: Does it Jeopardize the Outcome of Infants at Risk in Cairo University Neonatal Intensive Care Units (NICUs)?

Background: There is limited information on neonatal candidal urinary tract infection (UTI). Predisposing factors are prematurity, antimicrobial agents, and prolonged hospital stay. Objectives: To discuss the prevalence of candiduria among the risky neonates, to evaluate which of the predisposing factors has the highest risk of candiduria in Cairo University NICUs. We also tried to figure out the incidence of early complications (candidiasis and renal candidiasis) among candiduric neonates. Patients and Methods: We prospectively studied 50 neonates at risk [with gestational age (GA) 30-39 weeks] from Neonatal Intensive Care Units NICUs of Cairo University between January 2009 and September 2009. Urine samples were collected by sterile urethral catheterization under complete aseptic precautions. Studied cases were divided according to presence of candida in urine into two main groups: 1Group I (with candiduria) (n=16) [10 fullterm (FT) and 6 preterm (PT)]. 2Group II (without candiduria) (n=34). Blood cultures, Kidney function tests and renal ultrasound were ordered for certain cases to exclude candidiasis. Results: The incidence of candiduria among neonates at risk was 32% of case. There was no significant difference between the two groups as regard GA sex, duration of either hospital stay, or antibiotic therapy. However, certain antibiotic combinations were associated with higher incidence of candiduria. Conclusion: Neonatal candidal UTI, may be associated with morbidity and mortality. Routine urine analysis (especially for neonates with risk factors) is recommended to start antifungal therapy. Periodic re-evaluation of the feedback of antibiotic therapy protocols-in NICUsis mandatory.

Clinical and ultrasonographical characterization of childhood cystic kidney diseases in Egypt

Abstract Background: Renal cystic disorders (RCD) constitute an important and leading cause of end-stage renal disease (ESRD) in children. It can be acquired or inherited; isolated or associated with extrarenal manifestations. The precise diagnosis represents a difficult clinical challenge. Methods: The aim of this study was to define the pattern of clinical phenotypes of children with renal cystic diseases in Pediatric Nephrology Center, Cairo University. We have studied the clinical phenotypes of 105 children with RCD [45 (43%) of them had extrarenal manifestations]. Results: The most common disorders were the presumably inherited renal cystic diseases (65.7%) mainly nephronophthisis and related ciliopathies (36.2%), as well as polycystic kidney diseases (29.5%). Moreover, multicystic dysplastic kidneys accounted for 18% of study cases. Interestingly, eight syndromic cases are described, yet unclassified as none had been previously reported in the literature. Conclusion: RCD in this study had an expanded and complex spectrum and were largely due to presumably inherited/genetic disorders (65.7%). Moreover, we propose a modified algorithm for clinical and diagnostic approach to patients with RCD.

Fetuin-A and Ghrelin Levels in Children with End Stage Renal Disease and the Effect of a Single Hemodialysis Session on Them

BACKGROUND: Fetuin-A and ghrelin have been implicated in cardiovascular diseases and mortality among end stage renal disease patients. The exact mechanisms have not been fully elucidated. There is robust data supporting an association between ghrelin and various cardiovascular conditions, and some common processes such as inflammation, oxidative stress, and endoplasmic reticulum stress have been implicated. AIM: This study was conducted to assay serum fetuin-A and ghrelin in chronic renal failure pediatric patients and to study changes in their level that may occur after a single hemodialysis. MATERIAL AND METHODS: Forty nine pediatric patients suffering from ESRD on maintenance hemodialysis (HD), 20 patients with chronic renal failure (CRF) not on dialysis and 35 healthy subjects as control group were included. The mean age of the study population was 10.58 ± 3.94, 10.62 ± 3.24 and 10.61 ± 3.97 years respectively. Serum fetuin-A and plasma acyl ghrelin levels were measured by using ELISA method. RESULTS: The present study revealed that predialysis serum fetuin-A level was significantly increased in pediatric HD patients compared with the normal population, while ghrelin levels were significantly reduced. Furthermore, serum levels of fetuin-A decreased significantly after a single HD session. CONCLUSION: Our study concluded that fetuin-A and acyl ghrelin may play a role in inflammatory process among HD pediatric patients which may account for cardiovascular insults and mortality but their use as biochemical markers among ESRD pediatric patients have limitations due to wide fluctuations.

Plasminogen activator inhibitor-1 4G/5G gene polymorphism in hemodialysis patients with cardiovascular disease

Background Plasminogen activator inhibitor-1 (PAI-1) exerts antifibrinolytic and profibrotic activities and it plays an important role in renal fibrosis. Moreover, PAI-1 is also considered as a risk factor for cardiovascular disease. A 4G/5G polymorphism of the PAI-1 gene has been described associating the 4G haplotype with higher PAI-1 plasma activity. The aim of this study was to examine the frequency and distribution of the 4G/5G PAI-1 genotypes in patients with end-stage renal disease (ESRD) who developed cardiovascular complications in the form of hypertension, echocardiographic changes, and vascular thrombosis and the possible link(s) between them. Materials and methods We studied 40 patients with ESRD who had cardiovascular complications: 20 patients on hemodialysis (50%), 10 on conservative treatment (25%), and 10 subjected to renal transplantation (25%), in addition to 30 healthy individuals who served as controls. Genotyping of the PAI-1 gene was performed using allele-specific PCR method. Results The homozygous 4G/4G genotype was more frequent than the other genotypes (heterozygous 4G/5G and wild 5G/5G) among patients when compared with controls with a statistically significant difference ( P =0.01). A significant difference was also found on comparing the presence of the mutant 4G allele (in 4G/4G and 4G/5G genotypes) or its absence (in the 5G/5G genotype) between patients and controls ( P =0.04). On studying the genotyping of the four different groups, we found that the 4G/4G genotype was more prevalent among hemodialysis group, the 4G/5G was more prevalent among transplanted group, whereas the 5G/5G genotype was more frequent in the control group, and these differences were highly significant statistically ( P =0.005). For the genotype frequencies and their potential associations with cardiovascular complications and/or different laboratory findings, we only found a nearly significant association between the presence of the mutant 4G allele and lower high-density lipoprotein cholesterol levels ( P =0.08). Among patients who were subjected to renal transplantation, all patients who developed cardiovascular complications (50%), increased creatinine (10%), or repeated graft rejections (40%) had the heterozygous genotype (4G/5G) with the mutant 4G allele. Conclusion We found that the 4G/4G genotype in addition to the mutant 4G allele was more frequent among patients with ESRD compared with controls. The presence of the 4G mutation showed a nearly significant association with lower high-density lipoprotein cholesterol levels, suggesting that it could play a role in the pathogenesis of accelerated atherosclerotic heart disease in uremic patients.

Nutritional Status in Children with Chronic Renal Failure on Hemodialysis

Abstract Background and Aim: Growth retardation is still an important manifestation of children with chronic renal failure (CRF). The aim of this study is to evaluate the growth in relation to nutritional status in Egyptian children with CRF on hemodialysis. Subjects and Methods: The study included 30 Egyptian children above the age of six years on regular haemodialysis at the Haemodialysis Unit of the Centre of Pediatric Nephrology and Transplantation of Cairo University. Anthropometry, biochemical parameters and dietary intake were measured. Anthropometric measurements were expressed as z - scores. Results: Data shows that height was the most affected anthropometric parameter. Short stature in CRF is proportionate and body weight is less affected than height. Dietary analysis showed that 76.7 % of patients had recommended dietary allowance of calories. Height z-score showed a significant positive correlation with caloric intake. On the other hand, the protein intake showed a significant positive correlation with blood urea nitrogen and a significant negative correlation with serum bicarbonate. Conclusions: Nutritional assessment is essential to the management of children with CRF. Anthropometry is a sensitive indicator of the nutritional status. The study recommends avoiding excessive protein intake to prevent metabolic acidosis and accumulation of toxic nitrogen waste products.