Prenatal diagnosis and epidemiology of multicystic kidney dysplasia in Europe

State of the Science for Kidney Disorders in Phelan-McDermid Syndrome: UPK3A, FBLN1, WNT7B, and CELSR1 as Candidate Genes

Phelan-McDermid syndrome (PMS) is a neurodevelopmental disorder caused by chromosomal rearrangements affecting the 22q13.3 region or by SHANK3 pathogenic variants. The scientific literature suggests that up to 40% of individuals with PMS have kidney disorders, yet little research has been conducted on the renal system to assess candidate genes attributed to these disorders. Therefore, we first conducted a systematic review of the literature to identify kidney disorders in PMS and then pooled the data to create a cohort of individuals to identify candidate genes for renal disorders in PMS. We found 7 types of renal disorders reported: renal cysts, renal hypoplasia or agenesis, hydronephrosis, vesicoureteral reflux, kidney dysplasia, horseshoe kidneys, and pyelectasis. Association analysis from the pooled data from 152 individuals with PMS across 22 articles identified three genomic regions spanning chromosomal bands 22q13.31, 22q13.32, and 22q13.33, significantly associated with kidney disorders. We propose UPK3A, FBLN1, WNT7B, and CELSR1, located from 4.5 Mb to 5.5 Mb from the telomere, as candidate genes. Our findings support the hypothesis that genes included in this region may play a role in the pathogenesis of kidney disorders in PMS.

Prenatal diagnosis and outcome of unilateral multicystic kidney

We reviewed the records of 144 patients. The mean gestational age at first US diagnosis was 27.5 ± 4.3 weeks. An anomaly of the contralateral kidney was detected in 25% of cases. An extrarenal anomaly was detected in 13.8%. Karyotype analysis was performed in 16.6% of cases and revealed trisomy 18 in 2 cases with extrarenal defects. Karyotype analysis was normal in all the patients who had isolated multicystic dysplastic kidney (MCDK). The diagnostic accuracy of prenatal ultrasound was 92.2%. Contralateral kidney anomaly was detected 33.9% of patients, and half of these were vesicoureteral reflux. Antihypertensive therapy was required in 2.6% of cases. Nephrectomy was performed in 8%, and partial or total involution of MCDK was achieved in 33.9% of patients. MCDK can be accurately diagnosed by prenatal sonography, and prognosis depends on extrarenal and contralateral renal abnormalities. In isolated cases, require of surgery is rare, and serial follow-up is suggested to determine involution.Impact statementWhat is already known on this subject? Multicystic dysplastic kidney (MCDK) is one of the most renal anomalies and is associated with numerous renal and extrarenal abnormalities. It can lead to severe consequences in the neonatal period.What do the results of this study add? The accuracy of prenatal ultrasonography is excellent for detecting MCDK. In isolated unilateral cases, chromosomal aberrations are low, and the majority of them involute spontaneously. A periodic follow-up of the contralateral kidney is mandatory due to an increased risk of an anomaly. Genital anomaly risk is increased in males.What are the implications of these findings for clinical practice and/or further research? Detailed evaluation and follow-up of the contralateral kidney are crucial for counselling in isolated cases. Karyotype analysis in isolated unilateral MCDK is debateable. Postnatal prognosis is encountering, and the majority of patients have no requirement of surgery.

Bardet-Biedl syndrome: Antenatal presentation of forty-five fetuses with biallelic pathogenic variants in known Bardet-Biedl syndrome genes

Bardet-Biedl syndrome (BBS) is an emblematic ciliopathy associated with retinal dystrophy, obesity, postaxial polydactyly, learning disabilities, hypogonadism and renal dysfunction. Before birth, enlarged/cystic kidneys as well as polydactyly are the hallmark signs of BBS to consider in absence of familial history. However, these findings are not specific to BBS, raising the problem of differential diagnoses and prognosis. Molecular diagnosis during pregnancies remains a timely challenge for this heterogeneous disease (22 known genes). We report here the largest cohort of BBS fetuses to better characterize the antenatal presentation. Prenatal ultrasound (US) and/or autopsy data from 74 fetuses with putative BBS diagnosis were collected out of which molecular diagnosis was established in 51 cases, mainly in BBS genes (45 cases) following the classical gene distribution, but also in other ciliopathy genes (6 cases). Based on this, an updated diagnostic decision tree is proposed. No genotype/phenotype correlation could be established but postaxial polydactyly (82%) and renal cysts (78%) were the most prevalent symptoms. However, autopsy revealed polydactyly that was missed by prenatal US in 55% of the cases. Polydactyly must be carefully looked for in pregnancies with apparently isolated renal anomalies in fetuses.

[Kidney Cysts and Cystic Nephropathies in Children - A Consensus Guideline by 10 German Medical Societies]

This consensus-based guideline was developed by all relevant German pediatric medical societies. Ultrasound is the standard imaging modality for pre- and postnatal kidney cysts and should also exclude extrarenal manifestations in the abdomen and internal genital organs. MRI has selected indications. Suspicion of a cystic kidney disease should prompt consultation of a pediatric nephrologist. Prenatal management must be tailored to very different degrees of disease severity. After renal oligohydramnios, we recommend delivery in a perinatal center. Neonates should not be denied renal replacement therapy solely because of their age. Children with unilateral multicystic dysplastic kidney do not require routine further imaging or nephrectomy, but long-term nephrology follow-up (as do children with uni- or bilateral kidney hypo-/dysplasia with cysts). ARPKD (autosomal recessive polycystic kidney disease), nephronophthisis, Bardet-Biedl syndrome and HNF1B mutations cause relevant extrarenal disease and genetic testing is advisable. Children with tuberous sclerosis complex, tumor predisposition (e. g. von Hippel Lindau syndrome) or high risk of acquired kidney cysts should have regular ultrasounds. Even asymptomatic children of parents with ADPKD (autosomal dominant PKD) should be monitored for hypertension and proteinuria. Presymptomatic diagnostic ultrasound or genetic examination for ADPKD in minors should only be done after thorough counselling. Simple cysts are very rare in children and ADPKD in a parent should be excluded. Complex renal cysts require further investigation.

Impact of prenatal ultrasound diagnosis for fetal renal abnormalities: Study Protocol

BACKGROUND

This study will evaluate diagnostic accuracy and management outcome studies involving patients assessed with prenatal ultrasound diagnosis (PUD) for fetal renal abnormalities (FRA).

METHODS

We will search the following electronic databases of MEDLINE, EMBASE, Cochrane Library, Web of Science, Springer, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure for diagnostic accuracy studies from inceptions to the present without language restrictions. Two authors will independently screen studies, collect data, and assess methodological quality.We will use RevMan V.5.3 and Stata V.12.0 software for data pooling and statistical analysis.

RESULTS

In this study, we will assess sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio to determine the diagnostic accuracy of PUD for the treatment of patients with FRA.

CONCLUSION

This study will provide latest evidence for the diagnostic accuracy of PUD for FRA.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019151306.

Magnetic resonance imaging for evaluation of foetal multicystic dysplastic kidney

We sought to evaluate the diagnostic value of foetal magnetic resonance imaging (MRI) for multicystic dysplastic kidney (MCDK) disease. We retrospectively identified 55 foetuses with MCDK diagnosed (51 unilateral; 4 bilateral) by foetal MRI. We analysed the anatomical findings by prenatal MRI and compared them with the prenatal ultrasound (US) and postnatal findings. Additional diagnostic information added by MRI was recorded. The gestational age of the 55 foetuses ranged from 22 to 35 weeks (mean, 26.5 ± 3.6 weeks). The age of the pregnant women ranged from 23 to 40 years (mean, 31 ± 4.2 years). All 55 cases were performed at 1.5 T magnetic resonance unit. MRI sequences, including steady-state free precession (SSFP), single-shot fast spin echo (SSFSE), T₁-weighted imaging (T₁WI), and diffusion weighted imaging (DWI) sequences. Follow-up was obtained for 53 cases (2 cases of autopsy, 51 cases of postnatal imaging or surgery confirmed). Among the 51 unilateral cases, 16 cases were associated with other urinary tract anomalies, 3 cases with extra-renal anomalies, and the remaining 32 cases without associated anomalies. 2 of 16 cases with contralateral renal agenesis were with oligohydramnios and pulmonary hypoplasia. 2 of 4 bilateral MCDK presented with oligohydramnios and pulmonary hypoplasia. 52 of 53 cases were correctly diagnosed by MRI compared with the final diagnoses; 40 of 53 (75.5%) cases were correctly diagnosed by prenatal ultrasound. Both prenatal ultrasound and MRI failed to correctly diagnose one case bilateral MCDK, and MRI correctly changed the ultrasound diagnosis in 12 cases. Foetal MRI can add additional diagnostic information to prenatal US in the assessment of MCDK, even change the prenatal counselling and decisions.

Retrospective study to identify risk factors for chronic kidney disease in children with congenital solitary functioning kidney detected by neonatal renal ultrasound screening

To evaluate the prognostic significance of factors frequently associated with a reduction in renal mass, such as prematurity, low birth weight, and congenital anomalies of kidney and urinary tract (CAKUT), in patients with solitary functioning kidney (SFK) and investigate signs of early renal injury due to glomerular hyperfiltration damage or dysplasia in the remaining kidney.Retrospective observational study of congenital SFK diagnosed and followed at a tertiary care hospital over a period of 10 years in which 32,900 newborns underwent routine neonatal abdominal ultrasound screening. We analyzed age at diagnosis, sex, gestational age, anthropometric measurements at birth and prenatal and neonatal ultrasound findings, in addition to follow-up data corresponding to imaging findings (ultrasound, micturating cystourethrography, dimercaptosuccinic acid renal, and scintigraphy), ipsilateral CAKUT, compensatory hypertrophy, and renal injury in the form of albuminuria, blood pressure, and estimated glomerular filtration rate (eGFR).In total, 128 congenital SFK cases were detected (1 per 257 live births). Of these, 117 (91.4%) were diagnosed by neonatal ultrasound screening and 44.5% of these had been previously identified by prenatal ultrasound. Neonatal ultrasound had a specificity of 100% and a sensitivity of 92.1%. Forty-five patients (35.2%) had ipsilateral CAKUT and the most common type was urinary collecting system anomalies (75.5%). Over a median follow-up of 6.3 years (1-10 years), compensatory renal hypertrophy was observed in 81 patients (63.7%), most of whom had ipsilateral CAKUT (76.1% vs 56.6% of patients without ipsilateral CAKUT). Albuminuria and hypertension were observed in 3.12% and 5% of patients, respectively, and both were associated with ipsilateral CAKUT (P < .05). In addition, 75% of albuminuria cases (P = .031), 83.3% of hypertension cases (P = .004), and 100% of decreased eGFRcases (P = .031) were significantly associated with CAKUT (renal parenchymal anomaly category), being the strongest predictor of GFR the presence or absence of CAKUT.Neonatal ultrasound screening is useful for the early diagnosis of SFK. The presence of ipsilateral CAKUT should be evaluated in all patients with SFK as congenital anomalies of the renal parenchyma are associated with a poorer prognosis. Because morbidity from CAKUTs may not develop until adulthood, patients should be closely followed throughout life.

Prenatal diagnosis of urinary tract anomalies, a cohort study in the Northern Netherlands

OBJECTIVE

To describe prevalence, time of diagnosis, and type of birth in children and fetuses with urinary tract (UT) anomalies after the introduction of the anomaly scan in the Netherlands in 2007.

METHODS

We selected, from a population-based congenital anomaly registry, children and fetuses with UT anomalies born between 2008 and 2014. Cases were defined according to type of UT anomaly and whether isolated or with associated anomalies. Information was collected on time of diagnosis and type of birth.

RESULTS

We included 487 cases. Total prevalence increased from 34.0 in 2008 to 42.3 per 10 000 births in 2014, mainly by an increase in anomalies of the collecting system. Almost 70% presented as isolated. Anomalies of the renal parenchyma were more often associated with genetic or other anomalies (47.3%) than anomalies of the collecting system (19.0%). The proportion of prenatally diagnosed cases increased from 59.3% in 2008 to 80.9% in 2014. Termination of pregnancy occurred in 14.8%, of which the majority were UT anomalies associated with a genetic disorder or other anomalies.

CONCLUSION

In the period after the introduction of the anomaly scan, we observed an increasing prevalence of anomalies of the collecting system, but no increase in termination of pregnancies.

Diagnostic accuracy of midtrimester antenatal ultrasound for multicystic dysplastic kidneys

OBJECTIVES

To establish the diagnostic accuracy of obstetric ultrasound at a tertiary fetal medicine center in the prenatal detection of unilateral and bilateral multicystic dysplastic kidney (MCDK) in fetuses in which this condition was suspected, and to undertake a systematic review of the relevant literature.

METHODS

This was a retrospective observational study of all cases referred to a regional tertiary fetal medicine unit due to suspicion of either unilateral or bilateral MCDK between 1997 and 2015. Diagnosis was confirmed by postnatal ultrasound reports or postmortem examination. The accuracy of prenatal ultrasound in the diagnosis of MCDK was calculated. Using a systematic search strategy we also performed a review of the literature regarding the prenatal diagnosis and diagnostic accuracy of MCDK.

RESULTS

We included 144 women in our analysis; 37 (25.7%) opted for pregnancy termination (TOP) (due to unilateral MCDK with additional abnormalities, suspected bilateral MCDK or severe obstructive uropathy). Complete pre- and postnatal data were available in 126 pregnancies, including 104 livebirths, 19 TOPs with postmortem findings available and three intrauterine fetal deaths. Two infants died shortly after birth (due to known bilateral MCDK or known cranial vault defect). The overall number of cases of MCDK confirmed postnatally was 100; of these, 98 were diagnosed prenatally (true positive), while two were thought to be hydronephrosis prenatally (false negative) and the diagnosis of MCDK was made after birth. In nine cases, the initial antenatal diagnosis of suspected MCDK was revised, either later in pregnancy (n = 2) or postnatally (n = 7) (false positive). Overall, the diagnostic accuracy in our population for the use of antenatal ultrasound to detect MCDK was 91.3%, while that reported in the existing literature was found to range from 53.3% to 100%. MCDK was isolated in the majority (71%) of cases, while in 29% of cases it was found to be associated with other renal and extrarenal fetal abnormalities.

CONCLUSIONS

Antenatal ultrasound had a diagnostic accuracy of about 91% in the prediction of postnatal MCDK and can therefore be used to guide antenatal counseling. However, prenatal or postnatal revision of the diagnosis occurred in about 7% of cases and parents should be counseled appropriately. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Multicystic dysplastic kidney: Assessment of the need for renal scintigraphy and the safety of conservative treatment

OBJECTIVES

To assess the need for implementing renal scintigraphy in the diagnosis of the multicystic dysplastic kidney (MCDK) and the safety of its conservative treatment.

MATERIAL AND METHODS

A retrospective study of patients with unilateral MCDK was conducted at our centre from January 2005 to August 2015. We calculated the positive predictive value (PPV) of ultrasonography, taking renal scintigraphy and pathology as the gold standard. We calculated a survival curve according to the Kaplan-Meier method to assess the annual probability of spontaneous resolution of the multicystic kidney.

RESULTS

Fifty-six patients were identified, 48 (85.7%) of whom had a prenatal diagnosis. Thirty eight (67.9%) of the patients were males, and the left side was affected in 33 (58.9%) of the patients. We observed associated urological abnormalities in 22 (39.29%) patients, with vesicoureteral reflux the most common (8, 14.29%). Seven patients (12.5%) developed renal failure. Forty-nine (87.5%) patients developed compensatory contralateral renal hypertrophy. Of the 33 patients who underwent surgery, the pathology results confirmed the MCDK diagnosis in 32. Compared with scintigraphy and pathology, the PPV of ultrasonography was 100% and 97%, respectively. The rate of spontaneous involution was 5.4% at 3 months of life, 11.3% at 2 years and 38.4% at 5 years.

CONCLUSIONS

In our experience, the conservative treatment of MCDK, until at least 5 years of age, is safe. Our data suggest that performing scintigraphy is not required for these patients, which means lower radiation exposure, as well as financial savings.

Unilateral Fetal Renal Abnormalities: Are They Really Isolated?

OBJECTIVES

Our objective was to describe the association between unilateral fetal renal abnormalities and other major anomalies that were not apparent in the second trimester.

METHODS

A review of the ultrasound database identified fetuses with suspected unilateral renal agenesis, unilateral multicystic dysplastic kidney, and renal ectopia from 2005 to 2014. Neonatal records were reviewed to identify anomalies not suspected in the second trimester, and postnatal imaging studies were reviewed. Categorical data were compared by &x003C7;(2) analysis and the Fisher exact test.

RESULTS

We identified 102 cases, including 36 with suspected renal agenesis, 28 with suspected multicystic dysplastic kidney, and 38 with suspected renal ectopia. There were 8 cases (7.8%) with major anomalies not suspected in the second trimester. In 5 cases (4.9%), there were no associated findings in the second trimester. There were no significant differences in the rates of unsuspected abnormalities between the 3 groups. There was a trend toward a higher rate of unsuspected anomalies in the cases with a single umbilical artery compared to those with a 3-vessel cord (28.6% vs 6.3%; P= .09).

CONCLUSIONS

In fetuses with unilateral renal abnormalities, major anomalies that were not suspected in the second trimester were uncommon. However, patients should be aware of the possibility that other major anomalies could subsequently be identified, and the outcome may depend on more than postnatal renal function.

Positive predictive value and completeness of prenatally assigned International Classification of Disease-10 kidney anomaly diagnoses in the Danish National Patient Registry

Objective

Restricting studies of severe congenital malformations to live-born children may introduce substantial bias. In this study, we estimated the attendance to the second-trimester fetal malformation screening program. We also estimated the positive predictive value (PPV) of prenatally assigned International Classification of Disease-10 diagnoses recorded in the Danish National Patient Registry (DNPR) and the completeness of case registration. We used kidney anomalies as an example.

Methods

We identified the proportion of all Danish live-born children from January 1, 2007 to December 31, 2012, who were scanned during the second trimester using the DNPR and the Civil Registration System. Details of all fetuses with specific kidney anomaly diagnoses according to the DNPR were retrieved. The PPV was estimated using the nationwide Astraia database of pregnancy medical charts or traditional medical charts, as gold standard. The completeness was assessed using the total number of cases estimated by the capture–recapture method.

Results

Of 372,263 live born infants, 97.3% were scanned during the second trimester. We identified 172 fetuses in the DNPR. Of these, 149 had kidney anomalies according to Astraia or medical chart review, corresponding to a PPV of 87% (95% CI: 81%–91%). The estimated completeness was 43% (95% CI: 38%–49%) for the DNPR and 75% (95% CI: 70%–79%) for Astraia.

Conclusion

Almost all live-born children were scanned during the second trimester in Denmark. However, low completeness may hamper the use of the DNPR for studies of prenatally detected severe malformations, and use of the Astraia database may preferably be considered.