ystic kidney diseases are being diagnosed earlier and earlier (1) because of more accessible routine prenatal US and advances in US technology. However, differential diagnosis often remains a challenge because kidney cysts can arise in a large variety of illnesses, imaging patterns evolve over time, and extrarenal features of systemic diseases may not be present at a young age. Thus, imaging findings for a particular disease in newborns may be different from those in adolescents, and predicting prognosis or deciding on optimal follow-up intervals can be challenging. Imaging can contribute not only to accurate diagnosis and prognosis but also to rational management of cystic nephropathies. In adults with autosomal dominant polycystic kidney disease (ADPKD), for example, total kidney volume measured at MRI has emerged as a useful tool with which to identify patients who will benefit from treatment (2); however, transfer and adaptation of these findings to children is still an important research need. The purpose of this consensus statement is to establish uniform standards for choosing the correct imaging modality and diagnostic criteria for the most common cystic kidney diseases in childhood and adolescence and to propose rational approaches to diagnosis and follow-up in important clinical settings. The spectrum of diseases covered here includes simple cysts; multicystic dysplastic kidneys (MCDKs); cystic dysplasia and HNF1B-associated disease; autosomal recessive polycystic kidney disease (ARPKD) and ADPKD; other ciliopathies, such as nephronophthisis and Bardet-Biedl syndrome; acquired cystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease in adults, with an estimated prevalence of 1 in 500-2,500 (refs 1-4). Cyst development starts early in life, and macroscopic cysts can become detectable in childhood. Substantial disease burden with massively enlarged kidneys or decreased glomerular filtration rate (GFR) usually does not occur until adulthood 5 ; however, approximately 3% of children who carry ADPKD-causing mutations have either very-early-onset or unusually rapid progressive disease 5-7. Thus, the absolute incidence of symptomatic ADPKD in childhood is thought to be higher than that of other severe paediatric kidney diseases such as autosomal recessive polycystic kidney disease (~1 in 20,000), nephrotic syndrome (~1 in 50,000) 8 or haemolytic uraemic syndrome (~1 in 100,000 children) 9. The past 25 years have seen remarkable progress in knowledge of ADPKD. Advances have been made in unravelling the genetic origins of the disease, in noninvasive monitoring and in predicting disease progression; multiple large-scale clinical trials have been conducted; and the first pharmacological treatment for

IMPORTANCEPrenatal and neonatal cystic kidney diseases are a group of rare disorders manifesting as single, multiple unilateral, or bilateral cysts or with increased echogenicity of the renal cortex without macroscopic cysts. They may be accompanied by grossly enlarged kidneys, renal oligohydramnios, pulmonary hypoplasia, extrarenal abnormalities, and neonatal kidney failure. The prognosis is extremely variable from trivial to very severe or even uniformly fatal, which poses significant challenges to prenatal counseling and management.OBJECTIVE To provide a clinical practice recommendation for fetal medicine specialists, obstetricians, neonatologists, pediatric nephrologists, pediatricians, and human geneticists by aggregating current evidence and consensus expert opinion on current management of cystic nephropathies before and after birth.METHODS After 8 systematic literature reviews on clinically relevant questions were prepared (including 90 studies up to mid-2016), recommendations were formulated and formally graded at a consensus meeting that included experts from all relevant specialties. After further discussion, the final version was voted on by all members using the Delphi method. The recommendations were reviewed and endorsed by the working groups on inherited renal disorders of the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) and European Society for Paediatric Nephrology (ESPN); the German Society of Obstetrics and Gynecology (DGGG), German Society of Perinatal Medicine (DGPM), and German Society of Ultrasound in Medicine (DEGUM); and the alliance of patient organizations, PKD International. RECOMMENDATIONSThe group makes a number of recommendations on prenatal and postnatal imaging by ultrasound and magnetic resonance imaging, genetic testing, prenatal counseling, in utero therapeutic interventions, and postnatal management of prenatal and neonatal cystic kidney diseases, including provision of renal replacement therapy in neonates. In addition to detailed knowledge about possible etiologies and their prognosis, physicians need to be aware of recent improvements and remaining challenges of childhood chronic kidney disease, neonatal renal replacement therapy, and intensive pulmonary care to manage these cases and to empower parents for informed decision making.

CLKT and sequential KALT are decided on a case-by-case basis in children for special indications such as ARPKD or PH1. We report on 21 children who underwent CLKT or KALT at our hospital between 1998 and 2013. Eleven children were diagnosed with PH1 and six with ARPKD. Other diagnosis were Joubert syndrome (n = 1), nephronophthisis (n = 1), CF (n = 1), and hepatocellular carcinoma (n = 1). Children (12 males, nine females) were aged 7.8 ± 6.2 yr (range, 10 months to 18 yr) at time of transplantation. Average wait time was 1.9 ± 0.9 yr (range, four months to 2.3 yr). Fifteen patients received dialysis prior to transplantation. In PH1 patients, four children received CLKT, five received KALT, and two infants have received only an LTx, whereas all six patients with ARPKD received CLKT. In patients with other indications, CLKT was performed in three cases and KALT in one girl. Cumulative 10-yr survival of all 21 patients was 78.4%. At the time of transfer into adult care, 13 patients retained stable liver and kidney function. Regardless the underlying diagnosis, CLKT and KALT can be performed in children with good surgical outcomes and long-term survival.

HEV infection appears to be an emerging disease in industrialized countries. The aim of this study was to evaluate the prevalence of HEV infection in pediatric solid organ transplant recipients. One hundred and twenty-four pediatric recipients of liver (n = 41) or kidney (n = 83) transplants aged between one and 18 yr were screened for anti-HEV IgG antibodies. Patients were tested for fecal HEV RNA excretion if they showed anti-HEV seropositivity. As a control group, 108 immunocompetent pediatric patients without liver disease aged between three and 18 yr were screened for anti-HEV IgG. HEV seroprevalence was 2.4% in renal Tx (2/83), 4.9% in liver Tx patients (2/41), and 3.2% overall (4/124). Three of these four patients were HEV RNA-negative. In one renal transplant patient, HEV genotype 3 RNA excretion persisted and liver enzymes were elevated, indicating chronic hepatitis. In the control group, eight patients (7.4%) were HEV IgG-positive without biochemical evidence of hepatitis. The prevalence of HEV infection in pediatric renal or liver transplant recipients is not higher compared with immunocompetent children. Chronic HEV infection with long-term carriage of the virus may develop in pediatric transplant recipients. Autochthonous HEV infection needs to be considered in uncertain cases of hepatitis in immunosuppressed as well as immunocompetent children.