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Significance Statement: Congenital obstructive uropathy (COU) is a prevalent human developmental defect with highly heterogeneous clinical presentations and outcomes. Genetics may refine diagnosis, prognosis, and treatment, but the genomic architecture of COU is largely unknown. Comprehensive genomic screening study of 733 cases with three distinct COU subphenotypes revealed disease etiology in 10.0% of them. We detected no significant differences in the overall diagnostic yield among COU subphenotypes, with characteristic variable expressivity of several mutant genes. Our findings therefore may legitimize a genetic first diagnostic approach for COU, especially when burdening clinical and imaging characterization is not complete or available., Background: Congenital obstructive uropathy (COU) is a common cause of developmental defects of the urinary tract, with heterogeneous clinical presentation and outcome. Genetic analysis has the potential to elucidate the underlying diagnosis and help risk stratification., Methods: We performed a comprehensive genomic screen of 733 independent COU cases, which consisted of individuals with ureteropelvic junction obstruction ( n =321), ureterovesical junction obstruction/congenital megaureter ( n =178), and COU not otherwise specified (COU-NOS; n =234)., Results: We identified pathogenic single nucleotide variants (SNVs) in 53 (7.2%) cases and genomic disorders (GDs) in 23 (3.1%) cases. We detected no significant differences in the overall diagnostic yield between COU sub-phenotypes, and pathogenic SNVs in several genes were associated to any of the three categories. Hence, although COU may appear phenotypically heterogeneous, COU phenotypes are likely to share common molecular bases. On the other hand, mutations in TNXB were more often identified in COU-NOS cases, demonstrating the diagnostic challenge in discriminating COU from hydronephrosis secondary to vesicoureteral reflux, particularly when diagnostic imaging is incomplete. Pathogenic SNVs in only six genes were found in more than one individual, supporting high genetic heterogeneity. Finally, convergence between data on SNVs and GDs suggest MYH11 as a dosage-sensitive gene possibly correlating with severity of COU., Conclusions: We established a genomic diagnosis in 10.0% of COU individuals. The findings underscore the urgent need to identify novel genetic susceptibility factors to COU to better define the natural history of the remaining 90% of cases without a molecular diagnosis., (Copyright © 2023 by the American Society of Nephrology.)

Hydronephrosis in children is most often due to an intrinsic ureteropelvic junction obstruction or by compression on ureter by accessory renal artery coming from the aorta to the lower pole of the kidney., Aim: The aim of study was to present a case with a late onset of hydronephrosis caused by accessory renal artery., Case Report: 5-year old boy with a mild pyelectasia during first 10 months of age was admitted to hospital because of abdominal pain and vomiting. Abdominal ultrasound revealed a marked dilatation of the right pelvicalyceal system with renal pelvis measuring 23 mm in anterior-posterior (ap) diameter, enlargement of calyces to 10 mm and narrowed cortex to 5 mm. Dynamic scintigraphy (99mTc-EC) showed right-sided hydronephrosis with decreased isotope intake up to 31%, prolonged time of tissue perfusion and signs of ureteropelvic junction obstruction. Computed tomography urography with vascular option revealed right kidney length of 116 mm with narrow cortex, and dilated renal pelvis up to 53x52x28 (ap) mm and dilated calyces up to 16 mm. Apart from dilated collecting system, the computed tomography showed two renal arteries: normal artery coming from the aorta at the L1 level and the accessory renal artery, which originated from the aorta to the lower pole of the kidney at the L2/L3 level. The accessory renal artery compressed on the ureter causing hydronephrosis. The pyeloplasty modo Hynes-Anderson was performed. After 3 months an abdominal ultrasound revealed the right kidney of 89 mm in length with only moderate hydronephrosis: dilatation of renal pelvis up to 15-18 mm and calyces up to 7-8 mm. Scintigraphy showed isotope intake 48%., Conclusions: Hydronephrosis caused by accessory renal artery can be asymptomatic, with mild dilatation of pyelocalyceal system seen on abdominal ultrasonography. The first clinical symptoms may occur after several years and be associated with large hydronephrosis., (© 2018 MEDPRESS.)

Pyonephrosis in the course of hydronephrosis usually provides to total or near-total loss of renal function. In adults pyonephrosis usually results from urolithiasis. In children usually congenital urinary tract anomalies are present as contributing factors., Case Report: 6-year old girl was admitted to the hospital because of 2-day history of high fever, abdominal pain, progressive deterioration of general condition and ultrasonographically (US) detected left hydronephrosis. US on admission showed grossly dilated left renal collecting system together with extensive echogenic debris and laboratory tests highly elevated inflammatory markers. Once diagnosis of pyonephrosis was established on the basis of clinical picture and US as well as laboratory tests results, nephrostomy tube was placed percutaneously. Pus culture obtained during placement of nephrostomy showed E.Coli ESBL (-) growth. Intensive antibiotic treatment (Meropenem) was continued for 3 weeks, nephrostomy was removed after 12 days after receiving normal urine. Further evaluation of urinary tract (US and computed tomography urography) showed large hydronephrosis due to ureteropelvic junction obstruction, while dynamic scintigraphy obstructive renogram with grossly diminished left kidney function to 20% of differential renal function. The girl was referred for operative treatment on urgent basis. Intraoperatively long distance utreteropelvic junction stenosis was found and dismembered Anderson- Hynes pyeloplasty was performed. During 2-years follow-up postoperatively US showed gradually decrease of dilatation of left renal collecting system, while dynamic scintigraphy revealed permanent improvement of drainage together with almost normal renal function (up to 45%). No urinary tract infections were noted., Conclusions: Proper management of pyonephrosis in hydronephrotic kidney due to congenital ureteropelvic junction obstruction enables good final result of treatment., (© 2018 MEDPRESS.)

The incidence of horseshoe kidney is 1 per 400-800 live births. From 44-52% of the patients with horseshoe kidney have other coexisting abnormalities of the urinary tract, such as hydronephrosis, vesicoureteral reflux and a duplex collecting system. Our patient, a 5-year old boy, was admitted to a pediatric nephrology department because of abdominal pain and vomiting. He had ultrasonography of the abdomen performed for the first time at the age of 9-months and horseshoe kidney was shown. In a control ultrasonography, a mild dilatation of the pyelocalyceal system in the left kidney was described. On the day of admission, an abdominal ultrasound confirmed horseshoe kidney with large left hydronephrosis. Power Doppler ultrasonography showed two renal arteries to the left kidney and no arterial compression on the ureter. Dynamic scintigraphy (99mTc-EC) revealed left-sided hydronephrosis with high isotope intake up to 55% ERPF, a prolonged time of tissue perfusion and signs of subpelvic junction obstruction. Magnetic resonance urography presented an enlarged left kidney, with a diameter of up to 105 mm, a narrow renal cortex, a dilated renal pelvis up to 39 mm in diameter, dilated calyces up to 26-32 mm, and the high insertion of the ureter from the pelvis. The right kidney was normal. To facilitate drainage from the dilated collecting system of the left kidney, a double-J catheter was inserted. Pyeloplasty is planned as the next step of treatment. Conclusion: In a child with horseshoe kidney and a mild dilatation of the collecting system detected in infancy, long-term follow up is necessary, because of the increased risk of significant hydronephrosis in the future.

Background: Hydronephrosis is the one of the most common congenital abnormalities of urinary tract. The left kidney is more commonly affected than the right side and is more common in males., Aim of the Study: To determine the role of ultrasonography, renal dynamic scintigraphy and lowerdose computed tomography urography in preoperative diagnostic workup of infant with extreme hydronephrosis., Case Report: We presented the boy with antenatally diagnosed hydronephrosis. In serial, postnatal ultrasonography, renal scintigraphy and computed tomography urography we observed slightly declining function in the dilated kidney and increasing pelvic dilatation. Pyeloplasty was performed at the age of four months with good result., Conclusions: Results of ultrasonography and renal dynamic scintigraphy in child with extreme hydronephrosis can be difficult to asses, therefore before the surgical procedure a lower-dose computed tomography urography should be performed.

Unlabelled: There are many controversies related to diagnosis of significant urodynamically uretropelvic junction obstruction (UPJO) in children with congenital hydronephrosis (CHN). We compared three imaging methods: ultrasonography (US), diuretic renography (DR) and urography. We studied 23 children with CHN in mean age 6.8 +/- 10.4 months. Despite similar antero-posterior kidney diameter in US, an obstruction of urinary flow was seen significantly more often in urography than in DR. Agreement between DR and urography was noticed only in 32% of the kidneys., Conclusions: Recognition of UPJO in small children can be very difficult. An obstruction of urinary flow in DR can be associated not only with UPJO, but with immaturity of kidney and distensibility of the renal pelvis. Urography for imaging of CHN in small children can cause overdiagnosis of urodynamically significant UPJO and therefore too early surgical treatment.