Familial vesicoureteral reflux

Current options in the management of primary vesicoureteral reflux in children

The management of vesicoureteral reflux (VUR) is varied and remains controversial, which is likely because children with VUR have different risks for urinary tract infection or renal injury. Consequently, the treatment of VUR needs to be individualized based on the patient's characteristics. In this article, the authors review the medical and surgical management options for VUR in the pediatric population. The authors hope to provide a systematic approach to determine which treatment is optimal for a specific patient.

A genome scan in affected sib-pairs with familial vesicoureteral reflux identifies a locus on chromosome 5

The basis for vesicoureteral reflux (VUR) is considered to be primarily genetic, with a 30-50% incidence of VUR in first-degree relatives of patients. The search for the causative gene or genes has been elusive, likely because of VUR being genetically heterogeneous with complex inheritance patterns. In this study, a genome-wide analysis of VUR with high-density single nucleotide polymorphisms was conducted with the aim of identifying susceptibility loci for VUR in 98 families with two or more affected children. Using the affected sib-pair method of analysis in 150 sib-pairs, we identified a genome-wide statistically significant linkage peak with an LOD score greater than 4 on chromosome 5 and two linkage peaks with LOD scores greater than 3.6 on chromosomes 13 and 18 were identified in these 98 families. These results suggested that multiple genes are likely to contribute to the formation of VUR phenotype. Further mapping of these linkage peaks may help identify the causative genes.

Primary ureteral reflux: emerging insights from molecular and genetic studies

The incidence of primary vesicoureteral reflux is about 1% to 2% of the general population and is as high as 50% in siblings as well as offspring of affected patients, suggesting autosomal dominant inheritance. The current diagnosis of vesicoureteral reflux involves voiding cystourethrograms, which are invasive and costly. Consequently, vesicoureteral reflux screening in siblings and offspring is not routinely practiced, because of the known high risk. Early detection of vesicoureteral reflux will be valuable for prevention of reflux nephropathy, because the incidence of reflux nephropathy can be reduced effectively by antibiotic prophylaxis. Furthermore, the presence of reflux nephropathy can only be accurately assessed currently by dimercapto-succinic acid nuclear scans, which are costly, time and labor intensive, and often require conscious sedation by a pediatric anesthesiology team. As a result, the clinical assessment of reflux nephropathy is also not routinely practiced. There is a pressing need to develop less invasive and less costly tests for the early diagnosis of primary vesicoureteric reflux and reflux nephropathy. Recent molecular and genetic studies have greatly increased our understanding of vesicoureteral reflux and provide a promise of novel non-invasive tests. Targeted disruption of angiotensin type II receptor and uroplakin III genes result in the phenotype of primary vesicoureteral reflux. There are characteristic patterns of message and protein changes in the knockout animals, providing the basis for detection of genetic mutations leading to vesicoureteral reflux in humans by studying differential gene expression by functional genomics methodology. The urothelium is also known to secrete proteins into the urine. Preliminary studies showed unique fingerprints in urinary protein patterns in children with primary VUR, providing the basis for developing novel noninvasive molecular diagnostic tests of vesicoureteral reflux by proteomics methodology.

Silent renal damage in symptom-free siblings of children with vesicoureteral reflux: assessment with technetium Tc 99m dimercaptosuccinic acid scintigraphy

Sixteen symptom-free siblings of children with vesicoureteral reflux were found to have the condition and underwent renal scintigraphy with technetium 99m dimercaptosuccinic acid. Of these 16 children, 6 had scintigraphic evidence of renal damage. Screening for vesicoureteral reflux in siblings of children known to have the condition should therefore be carried out early in life; when reflux is present, an immediate assessment of the renal parenchyma should be made.

The transmission of vesicoureteral reflux from parent to child

Vesicoureteral reflux is now recognized to be hereditary and familial. The incidence of reflux in siblings has proved to be significant but less is known about the incidence of reflux in the offspring of known reflux patients. In an ongoing prospective series of reflux screening we identified 23 patients of childbearing age with a known history of reflux and screened their 36 offspring with an awake voiding cystourethrogram. Of these 36 offspring 24 (66%) exhibited vesicoureteral reflux. The literature was also reviewed to determine the incidence of parent/child reflux from reported cases. This review revealed a 65% rate of reflux in the offspring of known patients. Our preliminary results coupled with those in the literature signify a need to screen the offspring of known reflux patients and suggest a rethinking of the genetic transmission for this trait. While vesicoureteral reflux could still be a multifactorial genetic trait with a major gene, consideration must also be given to an autosomal dominant inheritance pattern.

Familial reflux: vesicoureteral reflux in all siblings of a family

A family is presented in which 4 of 4 (100%) siblings demonstrate vesicoureteral reflux on voiding cystogram. Mechanisms of inheritance are reviewed.

Screening of asymptomatic siblings of patients with vesicoureteral reflux

Familial trait in vesicoureteral reflux (VUR) has been revealed in many studies. This paper reports on 36 siblings of 25 patients operated for vesicoureteral reflux at our Department. Siblings aged 2 to 21 years were evaluated by urine examination, urine culture and voiding cystourethrogram (VCU) for VUR. All of the siblings were asymptomatic and VUR was found in only 4 of them (11%), unilateral in 3 cases and bilateral in one case. It is concluded that evaluation of siblings for VUR will be suitable for revealing the presence of urinary infection, and assessing them by VCU at the time they are first seen.

Vesicoureteric reflux and renal injury

Renal injury associated with the intrarenal reflux (IRR) of urine that is either infected, under high pressure, or both, is a major cause of severe hypertension during childhood and adolescence and of chronic renal insufficiency in patients less than 30 years of age. Many, but not all, adolescent and adult patients with reflux nephropathy (RN) give a history of urinary tract infection (UTI) or unexplained fevers in infancy or early childhood, when the kidney is thought to be at greatest risk of injury. Although vesicoureteric reflux (VUR) is observed more commonly in infants than children with UTI, it is rare in uninfected patients at any age and should never be considered a normal finding during human development. Renal scarring may not be obvious in radiographic or radionuclear studies to medical management alone, no definite benefit of one over the other was observed, regardless of the grade of VUR. Moreover, progressive renal injury in scarred kidneys has been noted even after VUR had been corrected, when infection had been prevented, and while hypertension had been controlled satisfactorily. Focal glomerular sclerosis, a lesion found in patients with proteinuria and RN, has been identified not only in scarred kidneys, but also may be seen in contralateral, unscarred kidneys without VUR, which might suggest a humoral factor or, perhaps, a hyperfiltration phenomenon. RN is one of the most frequent causes of end-stage renal disease (ESRD) in children, adolescents, and young adults, which is potentially preventable. However, prevention will depend on early identification of patients at risk--infants and young children after the first UTI and siblings of patients with VUR--aggressive and effective treatment of UTI, minimizing intravesical pressure, and education of patients, parents, and physicians.

Reflux nephropathy

The whole subject of reflux nephropathy, which may affect 1 in every 300 of the white female population, and is the second most common disease of the kidney in the young, is still bedevilled by a lack of information regarding many of its important aspects, and the absence of any coordinated action to obtain it. What is required above all else is a means of its early detection in very young children, so that it may be prevented, at least in its more severe forms. Its financial cost can only be surmised, but the treatment of its end-stages is likely to be in the region of a hundred million dollars a year. The cost in wastage involving, as it does, young people, particularly females, is incalculable.

Familial occurrence of nonobstructive, noninfectious vesicoureteral reflux with renal scarring

A family is described in which gross vesicoureteral reflux and renal scarring are present in the father and three sons, none with a history of urinary tract infection. Vesicoureteral reflux alone is present in an infant daughter. Father-to-son transmission of vesicoureteral reflux has not been previously reported. Autosomal dominant inheritance of the trait is suggested. The renal scarring noted in these patients may reflect generalized maldevelopment of affected renal units. The increasing recognition of vesicoureteral reflux as a familial trait suggests the need for evaluation of families in which vesicoureteral reflux is found in more than one member.