The Evaluation of Genetic Diagnosis on High-Risk Fetal CAKUT

Background: It is challenging to make an accurate prenatal diagnosis for congenital anomalies of the kidney and urinary tract (CAKUT) because of its pathologic diversity. This study aims to evaluate the performance of whole-exome sequencing (WES) combined with karyotype analysis and copy number variations (CNVs) in diagnosing high-risk fetal CAKUT. Methods: We conducted a retrospective study on prenatal diagnoses of CAKUT in our hospital from January 2020 to April 2021. The research studied 24 high-risk fetuses with CAKUT who were scanned by ultrasonography at the prenatal diagnosis center of Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology. The likely pathogenic gene variants were screened for the patients and their parents by multiple approaches, including karyotype analysis, CNVs and WES, and further verified with Sanger sequencing. Results: ①We detected abnormal CNVs in 20.8% (5/24) of the fetuses but only 8.3% (2/24) fetuses had abnormal karyotypes. ②Of the 15 CAKUT fetuses, positive findings (40%) were detected by WES. Of the 9 high-risk fetuses with CAKUT (negative findings in ultrasound scan but with family history), we found abnormal variants (77.8%) through WES. Conclusion: The application of CNVs and WES showed advance in prenatal diagnosis of CAKUT and the pathogenic gene variants were detectable especially for high-risk fetuses with negative ultrasound findings on CAKUT in the preliminary study. The applied strategy could be used to improve the accuracy of prenatal diagnosis for CAKUT in the future.

ACR Appropriateness Criteria® Antenatal Hydronephrosis-Infant

Antenatal hydronephrosis is the most frequent urinary tract anomaly detected on prenatal ultrasonography. It occurs approximately twice as often in males as in females. Most antenatal hydronephrosis is transient with little long-term significance, and few children with antenatal hydronephrosis will have significant obstruction, develop symptoms or complications, and require surgery. Some children will be diagnosed with more serious conditions, such as posterior urethral valves. Early detection of obstructive uropathy is necessary to mitigate the potential morbidity from loss of renal function. Imaging is an integral part of screening, diagnosis, and monitoring of children with antenatal hydronephrosis. Optimal timing and appropriate use of imaging can reduce the incidence of late diagnoses and prevent renal scarring and other complications. In general, follow-up neonatal ultrasound is recommended for all cases of antenatal hydronephrosis, while further imaging, including voiding cystourethrography and nuclear scintigraphy, is recommended for moderate or severe cases, or when renal parenchymal or bladder wall abnormalities are suspected. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Changes in differential renal function after pyeloplasty in infants and children

INTRODUCTION

Ureteropelvic junction obstruction (UPJO) is one of the most common causes of hydronephrosis in pediatric populations. Many need surgical intervention. The aim of surgery is preserving renal function and reducing symptoms such as urinary tract infections and pain.

OBJECTIVES

The objectives were to evaluate differential renal function (DRF) in infants and children after surgery for UPJO and to identify factors predicting postoperative improvement. The difference in outcomes between patients with antenatal hydronephrosis and those diagnosed later was evaluated.

STUDY DESIGN

A total of 85 children (63 boys and 22 girls) aged 0-16 years, treated for UPJO with dismembered pyeloplasty, were followed up as per a structured protocol including ultrasounds and renal scans (MAG-3) pre-operatively and three and 18 months postoperatively. Five children with bilateral or single kidney UPJO were excluded. Patient records were retrospectively reviewed, and the patients were grouped as per prenatal (group 1, n = 23) or postnatal (group 2, n = 57) diagnosis. Univariable and multivariable logistic regression analyses searching for factors predicting >5% postoperative improvement in DRF on the obstructed side were performed. Factors included in analyses were age at diagnosis and surgery, sex, type of presentation, cause of obstruction, estimated glomerular filtration rate, pre-operative DRF, anteroposterior diameter (APD), APD/renal parenchymal thickness, and grade of hydronephrosis as per the Onen alternative grading system (grade 1-4).

RESULTS

Pre-operative DRF on the obstructed side was a mean of 42% (standard deviation, 12), with no difference between the groups. The median age at surgery was 0.9 (0.2-10) and 8.1 (0.6-16) years in groups 1 and 2, respectively (P < 0.001). The majority had unchanged DRF 18 months postoperatively, 19 (27%) patients improved by >5%, and one deteriorated. The proportion of patients with improved DRF was higher in group 1 (n = 10; 45%, P = 0.026). Anteroposterior diameter, APD/parenchymal thickness, pre-operative DRF, and antenatal diagnosis were predictors in the univariable analyses, and high APD (odds ratio [OR] = 1.1, P = 0.0023), antenatal diagnosis (OR = 0.23, P = 0.048), and low pre-operative DRF (OR = 0.90, P = 0.0045) built the best model of independent factors predicting improvement in DRF in multivariable analyses (Summary Figure).

DISCUSSION

The limitation of the study is that it is retrospective, but it has the advantage of a uniform follow-up protocol, including patients from a five-year period, with few lost to follow-up. The results can be of interest in evaluating factors of importance for predicting recovery of function in obstructive uropathies in children.

CONCLUSION

The majority of children had preserved or improved function after surgery for UPJO. Those with an antenatal diagnosis displayed a greater ability to catch up in DRF, and high APD, antenatal diagnosis, and low pre-operative DRF were independent predictive factors of an improvement in renal function after pyeloplasty.

Moderate and severe fetal pyelectasis: Correlation between prenatal aspects and postnatal outcome

BACKGROUND

Renal pelvic dilatation (RPD) is a frequent finding in fetal ultrasound. The aim of the study is to correlate the prenatally detected moderate and severe pyelectasis with the postnatal outcome.

METHODS

A retrospective analysis involving 90 cases of prenatally detected moderate and severe RPD referred to our prenatal diagnosis centre with 18 months of urological follow-up. Prenatal ultrasound was correlated with postnatal renal function, assessed by plasmatic creatinine and/or renal scintigraphy performed before surgery.

RESULTS

Cases were divided between two groups according to postnatal management: group A including 35 newborns (38.9%) that needed surgical treatment and group B with 55 patients (61.1%) who were managed conservatively. The group A presented higher median RPD (18 mm, IQR 12-25 mm) compared to the group B (11 mm, IQR 10-14 mm). The most common anomaly detected within group A was pelvi-ureteric junction (PUI) obstruction (43%). Within group B 32 cases (58%) showed spontaneous resolution of hydronephrosis during postnatal follow up. In case of moderate pyelectasis the risk of postnatal surgery was 25% and raised to 60% for severe RPD. In our study, 29 newborns showed pathologic scintigraphies: 25 required surgery while 4 did not find indication for surgery due to ipsilateral renal function irreversible damage. 6 patients had high creatinine level (>0.6 mg/dl). 35 cases out of 90 (39%) developed monolateral irreversible renal function impairment.

CONCLUSION

Moderate and severe RPD are often correlated with postnatal renal damage, therefore a close multidisciplinary follow-up is required. Prenatal scanning is highly predictive of postnatal outcome and can address properly the prenatal counseling.

Evaluation of the clinical value of retroperitoneal laparoscopic pyeloplasty in the treatment of ureteropelvic junction obstruction in infants: A single-center experience involving 22 consecutive patients

Retroperitoneal laparoscopic pyeloplasty (RLP) is 1 method for treating ureteropelvic junction obstruction (UPJO) in children, but reports are more common in children than in infants younger than 2 years old. The purpose of this study was to evaluate the clinical value of RLP for infants with UPJO.From January 2015 to December 2017, a retrospective analysis of 22 infants aged 2 to 24 (11.95 ± 6.00) months with UPJO who were treated with RLP in our hospital was performed. During the same period, 14 infants who underwent conventional transperitoneal laparoscopic pyeloplasty (TLP) were compared with those who underwent RLP. Postoperative recovery and complications, including bleeding, infection, urinary leakage and anastomotic stenosis, postoperative resumption of oral feeding, postoperative hospitalization time and surgical success rate were evaluated. Drainage and function were assessed with isotope scan at 6 months and later during the yearly follow-up and by intravenous urography (IVU) and mercaptoacetyltriglycine (MAG3) renography.Both groups underwent successful surgery. The operative time in the RLP group was 88 to 205 (120.59 ± 24.59) min, and there was no significant difference compared with the TLP group (P = .767). The estimated intraoperative blood loss was 2 to 10 (3.75 ± 1.59) ml, which was not significantly different between the 2 groups (P = .386). In the RLP group, the mean postoperative resumption of oral feeding was faster than that in the TLP group (3.55 ± 0.74 vs 5.50 ± 0.85 hour, P < .001), and the postoperative hospitalization time was shorter in the TLP group than in the RLP group (6.59 ± 0.50 vs 7.07 ± 0.47 day, P = .007 < .05). Follow-up lasted from 6 months to 3 years, and there was a significant reduction in postoperative hydronephrosis in both groups (P < .05, respectively).RLP is a safe procedure for infants. This procedure is associated with relatively little trauma, a quick recovery and good cosmetic effects. RLP also has the advantages of relatively little interference with the abdominal cavity and sufficient operating space; thus, this technique is worth promoting.

Outcome after prenatal diagnosis of fetal urinary tract abnormalities: A tertiary center experience

Objective:

With the widespread use of ultrasonography for fetal screening, the detection and management of congenital urinary tract abnormalities has become crucial. In this study, we aimed to describe the clinical approaches in patients with prenatally detected urinary tract abnormalities.

Material and Methods:

This study is a retrospective, single-center study performed at a perinatology unit of a university hospital, between 2010 and 2016. The outcomes of 124 patients who were prenatally diagnosed as having urinary tract abnormalities are reported. Variables included in the analysis were fetal sex, birth week and weight, persistency, and necessity surgery after birth for renal pelvic dilatation. Low-risk renal pelvic dilatation was determined as an anterior-posterior (AP) diameter of 4-7 mm at 16-28 weeks, 7-10 mm after 28 weeks, whereas high-risk dilatation was defined as AP measurements of ≥7 mm at 16-28 weeks, ≥10 mm after 28 weeks, respectively.

Results:

The majority of patients consisted of male fetuses with bilateral pelviectasis (62.9%, 20.2%, respectively). The mean age was 28.8±6.4 years. The mean gestational age at birth was 34.2±7.8 weeks. The mean birth weight was 2593±1253.3 g. The need for surgery was greater in high-risk patients than in low-risk patients (58.3% vs. 8.7%) (p<0.002).

Conclusion:

Patients with high-risk antenatal renal pelvic dilatation require surgical treatment after delivery. Close prenatal and postnatal follow-up is mandatory in specialized centers. Perinatologists, neonatologists, pediatricians and pediatric nephrologists, and radiologists should treat these children with a multidisciplinary approach.

Renal development in the fetus and premature infant

Congenital abnormalities of the kidney and urinary tract (CAKUT) are one of the leading congenital defects to be identified on prenatal ultrasound. CAKUT represent a broad spectrum of abnormalities, from transient hydronephrosis to severe bilateral renal agenesis. CAKUT are a major contributor to chronic and end stage kidney disease (CKD/ESKD) in children. Prenatal imaging is useful to identify CAKUT, but will not detect all defects. Both genetic abnormalities and the fetal environment contribute to CAKUT. Monogenic gene mutations identified in human CAKUT have advanced our understanding of molecular mechanisms of renal development. Low nephron number and solitary kidneys are associated with increased risk of adult onset CKD and ESKD. Premature and low birth weight infants represent a high risk population for low nephron number. Additional research is needed to identify biomarkers and appropriate follow-up of premature and low birth weight infants into adulthood.

Revised guidelines on management of antenatal hydronephrosis

Widespread antenatal screening has resulted in increased detection of anomalies of the kidneys and urinary tract. The present guidelines update the recommendations published in 2000. Antenatal hydronephrosis (ANH) is transient and resolves by the third trimester in almost one-half cases. The presence of oligohydramnios and additional renal or extrarenal anomalies suggests significant pathology. All patients with ANH should undergo postnatal ultrasonography; the intensity of subsequent evaluation depends on anteroposterior diameter (APD) of the renal pelvis and/or Society for Fetal Urology (SFU) grading. Patients with postnatal APD exceeding 10 mm and/or SFU grade 3-4 should be screened for upper or lower urinary tract obstruction and vesicoureteric reflux (VUR). Infants with VUR should receive antibiotic prophylaxis through the first year of life, and their parents counseled regarding the risk of urinary tract infections. The management of patients with pelviureteric junction or vesicoureteric junction obstruction depends on clinical features and results of sequential ultrasonography and radionuclide renography. Surgery is considered in patients with increasing renal pelvic APD and/or an obstructed renogram with differential renal function <35-40% or its subsequent decline. Further studies are necessary to clarify the role of prenatal intervention, frequency of follow-up investigations and indications for surgery in these patients.