Genetics: The diagnostic frontier in pediatric urology.

In the course of human history few scientific breakthroughs can rival the importance of the discovery of DNA. Our ever increasing ability to unravel the secrets contained in this molecule allow new insight in to the etiology and eventual treatment of human conditions ranging from congenital structural disorders to cancer. It is the focus of this article to touch upon sequencing technologies and their potential to provide information that can revolutionize healthcare.

SLC20A1 Is Involved in Urinary Tract and Urorectal Development.

Previous studies in developing Xenopus and zebrafish reported that the phosphate transporter slc20a1a is expressed in pronephric kidneys. The recent identification of SLC20A1 as a monoallelic candidate gene for cloacal exstrophy further suggests its involvement in the urinary tract and urorectal development. However, little is known of the functional role of SLC20A1 in urinary tract development. Here, we investigated this using morpholino oligonucleotide knockdown of the zebrafish ortholog slc20a1a. This caused kidney cysts and malformations of the cloaca. Moreover, in morphants we demonstrated dysfunctional voiding and hindgut opening defects mimicking imperforate anus in human cloacal exstrophy. Furthermore, we performed immunohistochemistry of an unaffected 6-week-old human embryo and detected SLC20A1 in the urinary tract and the abdominal midline, structures implicated in the pathogenesis of cloacal exstrophy. Additionally, we resequenced SLC20A1 in 690 individuals with bladder exstrophy-epispadias complex (BEEC) including 84 individuals with cloacal exstrophy. We identified two additional monoallelic de novo variants. One was identified in a case-parent trio with classic bladder exstrophy, and one additional novel de novo variant was detected in an affected mother who transmitted this variant to her affected son. To study the potential cellular impact of SLC20A1 variants, we expressed them in HEK293 cells. Here, phosphate transport was not compromised, suggesting that it is not a disease mechanism. However, there was a tendency for lower levels of cleaved caspase-3, perhaps implicating apoptosis pathways in the disease. Our results suggest SLC20A1 is involved in urinary tract and urorectal development and implicate SLC20A1 as a disease-gene for BEEC.

An immediate, single intravesical instillation of mitomycin C is of benefit in patients with non-muscle-invasive bladder cancer irrespective of prognostic risk groups.

BACKGROUND: In a recent meta-analysis, subgroups of patients were defined that may not benefit from a single, immediate instillation with chemotherapy. This led to a change in the European Association of Urology bladder cancer guidelines. In a previous paper, our group confirmed the efficacy of an immediate instillation of mitomycin C (MMC). However, prognostic groups in that study differ from those in the meta-analysis. Therefore, we performed a reanalysis using contemporary risk groups. OBJECTIVES: To validate whether specific subgroups of patients with non-muscle-invasive bladder cancer (NMIBC) benefit from an immediate instillation with MMC. PATIENTS AND METHODS: All 2,243 NMIBC patients enrolled in our randomized controlled trial between 1998 and 2003 were analyzed. Treatment effect was investigated for all subgroups, including subgroups that did not benefit from an immediate instillation according to the meta-analysis. Time to recurrence was assessed using Kaplan-Meier curves and multivariable Cox regression. Differences in treatment effect between subgroups was tested using the variable treatment by covariate interactions in a Cox regression model. RESULTS: The difference in time to recurrence was statistically significant in favor of an immediate instillation with MMC (P < 0.001) which corresponds to a 25% risk reduction (hazard ratio: 0.75, 95% confidence interval, 0.64-0.88, P < 0.001). Treatment effect of an immediate instillation with MMC did not differ significantly between any of the subgroups. CONCLUSIONS: In contrast to the recommendations in the European Association of Urology guidelines, we could not identify any subgroup of patients with NMIBC who do not benefit from an immediate instillation with MMC after transurethral resection.

The effect of timing of an immediate instillation of mitomycin C after transurethral resection in 941 patients with non-muscle-invasive bladder cancer.

OBJECTIVE: To investigate whether the timing of an immediate instillation of mitomycin C (on the day of transurethral resection of bladder tumour [TURBT] or 1 day later) has an impact on time to recurrence of non-muscle-invasive bladder cancer (NMIBC). PATIENTS AND METHODS: All patients with NMIBC who were enrolled in a prospective trial between 1998 and 2003, and treated with an early mitomycin C instillation (on the day of TURBT or 1 day later), were selected. Statistical analysis was performed with Kaplan-Meier curves and multivariable Cox regression. RESULTS: Administering an instillation of mitomycin C on the day of TURBT or 1 day later did not show a statistically significant difference in time to recurrence in a univariable model (log-rank P = 0.99). After correcting for the number of scheduled adjuvant instillations, no statistically significant difference could be detected either: hazard ratio 1.05 (95% confidence interval 0.81-1.35, P = 0.74). CONCLUSION: These data do not support the hypothesis that a very early instillation (on the day of TURBT) of mitomycin C decreases the risk of recurrence as compared with an early instillation (1 day after TURBT).

Value of an Immediate Intravesical Instillation of Mitomycin C in Patients with Non-muscle-invasive Bladder Cancer: A Prospective Multicentre Randomised Study in 2243 patients.

BACKGROUND: The efficacy of an immediate single chemotherapy instillation after transurethral resection of a bladder tumour (TURBT) in patients with non-muscle-invasive bladder cancer (NMIBC) remains a topic of debate. Evidence is even more scarce when an immediate instillation is followed by adjuvant instillations. OBJECTIVE: To compare the effect of a mitomycin C (MMC) instillation within 24h to an instillation 2 wk after TURBT in patients with NMIBC with or without adjuvant instillations. DESIGN, SETTING, AND PARTICIPANTS: Between 1998 and 2003, 2844 NMIBC patients were randomised for immediate versus delayed MMC instillation after TURBT. Patients were categorised in low-risk (LOR), intermediate-risk (IMR), and high-risk (HIR) groups. Total numbers of instillations in these groups were 1, 9, and 15, respectively. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Primary end point was 3-yr recurrence risk for the IMR and HIR groups and 5-yr risk for the LOR group. Secondary outcomes were time to recurrence and incidence of adverse events. Analyses were performed with the log-rank test, Cox-regression, and χ2 test in SPSS. RESULTS AND LIMITATIONS: A total of 2243 patients were eligible on an intention-to-treat basis. Recurrence risks were 43% and 46% in the LOR group (5-yr follow-up, p=0.11), 20% and 32% in the IMR group (3-yr follow-up, p=0.037), and 28% and 35% in the HIR group (3-yr follow-up, p=0.007), for an immediate and a delayed instillation, respectively. For all patients, the recurrence risk was 27% (95% confidence interval [CI], 24-30) in the immediate and 36% (95% CI, 33-39) in the delayed instillation group (p<0.001) with a 27% reduction in relative recurrence risk (hazard ratio: 0.73, 95% CI, 0.63-0.85, p<0.001). The incidence of adverse events did not differ significantly between treatment groups (immediate instillation 25%, delayed instillation 22%, p=0.08). The risk groups in our study differ slightly from the current guidelines, which is a limitation of our study. CONCLUSIONS: An immediate, single instillation after TURBT reduces the recurrence risk in NMIBC patients, independent of the number of adjuvant installations. PATIENT SUMMARY: A single instillation of chemotherapy after the resection of non-muscle-invasive bladder cancer reduces the recurrence risk, even if patients are treated with an adjuvant schedule of instillations.

Case Presentation: Neurogenic Bladder in a Girl After Surgery for Cloacal Malformation.

A girl born in 2006 has been under close surveillance in our pediatric urology unit since birth. Besides cloacal malformation, she has associated spinal cord dysraphism, uterus didelphys, and a vaginal septum.

Development of an in vitro model to measure bioactivity of botulinum neurotoxin A in rat bladder muscle strips.

BACKGROUND: Botulinum toxin A (BoNT-A) is a new treatment modality in various causes of bladder dysfunction; like neurogenic detrusor overactivity and overactive bladder. The best technique of administrating BoNT-A in patients is unknown. A validated in vitro model could be used to investigate newer intravesical administration techniques of BoNT-A. In this study, we describe the development and validation of in vitro model to measure inhibitory effects of BoNT-A on bladder strip contractions. METHODS: Rat bladder strips were mounted in organ baths filled with Krebs' solution. The strips were stimulated chemically (80 mM potassium chloride, 1 µM carbachol) and electrically (Electrical Field Stimulation (EFS) 100 shocks, 50 V, 20 Hz, every 3 minutes). The viability of the strips was measured by carbachol stimulation at the beginning and at the end of the experiments. The strips were incubated in various concentrations of BoNT-A (0.03, 0.2, 0.3 nM). Controls were incubated in Krebs' solution only. The inhibition of strip contraction induced by EFS was measured. These measurements were statistically analyzed with a log-logistic model representing diffusion. RESULTS: All strips remained viable during the experiments. Inhibition of strip contraction was observed after incubation with 0.3 nM BoNT-A. The measurements fitted to a log-logistic model describing diffusion of BoNT-A in the bladder strip. The parameters of the log-logistic model representing diffusion were significant for 0.3 nM BoNT-A. Incubation with 0.2 nM BoNT-A showed insignificant results for 2 out of 3 runs. Incubation with 0.03 nM BoNT-A did not result in significant inhibition of strip contractions. CONCLUSIONS: An in vitro model was developed and validated in which the inhibitory effect of low concentrations of BoNT-A on bladder strip contractions can be measured.

Phenotype severity in the bladder exstrophy-epispadias complex: analysis of genetic and nongenetic contributing factors in 441 families from North America and Europe.

OBJECTIVE: To identify genetic and nongenetic risk factors that contribute to the severity of the bladder exstrophy-epispadias complex (BEEC). STUDY DESIGN: Patients with BEEC from North America (n = 167) and Europe (n = 274) were included. The following data were collected: associated anomalies, parental age at conception, mode of conception, periconceptional folic acid supplementation, maternal risk factors during pregnancy, and environmental risk factors. The patients were divided into 3 subgroups according to phenotype severity: (i) mild, epispadias (n = 43); (ii) intermediate, classic bladder exstrophy (n = 366); and (iii) severe, cloacal exstrophy (n = 31). These subgroups then were compared with identify factors that contribute to phenotype severity. RESULTS: Males were overrepresented in all subgroups. A relatively high prevalence of cleft lip, with or without cleft palate, was observed. Maternal smoking and medical radiation during the first trimester were associated with the severe cloacal exstrophy phenotype. Compliance with periconceptional folic acid supplementation was associated with the mildest phenotype (epispadias). CONCLUSIONS: Periconceptional folic acid supplementation appears to prevent the development of the severe phenotype of BEEC.

Urological and nephrological findings of renal ectopia.

PURPOSE: Urological characteristics of renal ectopia have been addressed previously but little is known about the functional consequences. We sought to study renal function, blood pressure, proteinuria and urological abnormalities in children with renal ectopia. As a secondary objective, we compared these parameters between simple and crossed ectopia. MATERIALS AND METHODS: For this retrospective, single center, observational study we reviewed case documents and radiological records. We also analyzed longitudinal data on blood pressure, proteinuria and kidney function. RESULTS: Renal ectopia was diagnosed in 41 cases, of which 26 (63%) were simple renal ectopia, ie unilateral pelvic kidney. In 32% of patients the diagnosis was made during prenatal screening. Median patient age was 0.24 years at diagnosis and 7.7 years at the most recent control visit. Associated urological abnormalities were found in 66% of patients. Voiding cystourethrography was performed in all patients, with vesicoureteral reflux shown in 13. In 8 of 10 cases with unilateral reflux the condition manifested in the orthotopic kidney. The relative function of the ectopic kidney on dimercapto-succinic acid scan was 38%, and in 22% of patients glomerular filtration rate was less than 90 ml per minute per 1.73 m(2). Albuminuria and proteinuria were absent in most cases. Longitudinal analysis of blood pressure, glomerular filtration rate and albuminuria revealed a stable course for all parameters. No substantial difference was observed between simple and crossed renal ectopia. CONCLUSIONS: Our data suggest no adverse effects on blood pressure or kidney function in children with renal ectopia. However, periodic followup seems warranted, at least until young adulthood.

Posterior urethral valves in three siblings: a case report and review of the literature.

BACKGROUND: Posterior urethral valves (PUVs), the most common congenital cause of lower urinary tract obstruction, have been described to occur in families. Until now, reports have been published on 10 cases of PUVs in two siblings and 13 cases of PUVs in identical and nonidentical twins, of which we provide an overview. CASES: We report for the first time on three siblings with PUVs, with a different presentation and course in the three brothers. This within-family variability is well noted and is even present in identical twins. CONCLUSIONS: This finding suggests that both genetic and environmental factors play a role in the presence and severity of PUVs. As brothers of patients with PUVs seem to be at increased risk of having PUVs, we suggest antenatal ultrasound screening in brothers of patients with PUVs in order to guide early and optimal care.