Monoallelic Loss-of-Function IFT140 Pathogenic Variants Cause Autosomal Dominant Polycystic Kidney Disease: A Confirmatory Study With Suspicion of an Additional Cardiac Phenotype

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease. While biallelic variants affecting IFT140 are responsible for Mainzer-Saldino syndrome (characterized by severe ciliopathy causing skeletal abnormalities, kidney disease, and cysts), monoallelic loss-of-function (LoF) variants have been recently reported as an important cause of ADPKD beyond PKD1/2 genes. Herein, we report 6 non-family-related cases of monoallelic IFT140 LoF variants, identified from 1,340 exomes sequenced for nephrological indications in our local database. Every patient presented with polycystic kidney disease. Furthermore, the mother of a boy diagnosed with Mainzer-Saldino syndrome with a biallelic variant affecting IFT140 presented with several bilateral cysts, revealed after kidney imaging, and was found to carry a pathologic frameshift IFT140 variation. As well as this particular Mainzer-Saldino case, our 6 additional patients confirm that heterozygous IFT140 frameshift variants are responsible for the cystic phenotype and kidney failure. Interestingly, of the 6 patients, 2 also exhibited dilated cardiomyopathy, which was of unknown origin, as no genetic cause was found after exome sequencing analysis, suggesting a potential connection between IFT140 and heart disease.

The screening, diagnosis, and management of patients with autosomal dominant polycystic kidney disease: A national consensus statement from Taiwan

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of end-stage kidney disease (ESKD) worldwide. Guidelines for the diagnosis and management of ADPKD in Taiwan remains unavailable. In this consensus statement, we summarize updated information on clinical features of international and domestic patients with ADPKD, followed by suggestions for optimal diagnosis and care in Taiwan. Specifically, counselling for at-risk minors and reproductive issues can be important, including ethical dilemmas surrounding prenatal diagnosis and pre-implantation genetic diagnosis. Studies reveal that ADPKD typically remains asymptomatic until the fourth decade of life, with symptoms resulting from cystic expansion with visceral compression, or rupture. The diagnosis can be made based on a detailed family history, followed by imaging studies (ultrasound, computed tomography, or magnetic resonance imaging). Genetic testing is reserved for atypical cases mostly. Common tools for prognosis prediction include total kidney volume, Mayo classification and PROPKD/genetic score. Screening and management of complications such as hypertension, proteinuria, urological infections, intracranial aneurysms, are also crucial for improving outcome. We suggest that the optimal management strategies of patients with ADPKD include general medical care, dietary recommendations and ADPKD-specific treatments. Key points include rigorous blood pressure control, dietary sodium restriction and Tolvaptan use, whereas the evidence for somatostatin analogues and mammalian target of rapamycin (mTOR) inhibitors remains limited. In summary, we outline an individualized care plan emphasizing careful monitoring of disease progression and highlight the need for shared decision-making among these patients.

US Veterans Administration Autosomal Dominant Polycystic Kidney Disease Cohort: Demographic, Comorbidity, and Key Laboratory Data Characteristics

Key Points

Background

We used the largest integrated US healthcare system, the Veterans Health Administration, to establish a robust resource for demographic, longitudinal outcome, and predictive modeling studies in autosomal dominant polycystic kidney disease (ADPKD).

Methods

We built the ADPKD cohort by extracting the relevant electronic health record data from nationwide Veterans Health Administration database (years 1999–2020).

Results

We identified 12,217 patients diagnosed with ADPKD. By the end of the 20-year study period, 5342 patients with ADPKD were deceased, 1583 were alive but reached ESKD, and 4827 remained alive without ESKD. Most demographic characteristics of this ADPKD cohort resemble the total US veteran population. For example, 94% were male patients, 45% age 65 years or older, 85% non-Hispanic, and 66% white; however, 19% were Black/African Americans (versus 12% in the general veteran population; a relevant enrichment after considering age and sex distributions between races). The comorbidities overrepresented in the ADPKD cohort include hypertension (89% versus 50%), diabetes (32% versus 22%), depression (40% versus 10%), chronic obstructive pulmonary disease (30% versus 6%), and congestive heart failure (21% versus 1%). By contrast, obesity was underrepresented in veterans with ADPKD (30% versus 41%).

Conclusions

We established a large electronic medical record-based cohort of ADPKD veterans. Here, we provide initial analysis of its demographic, comorbidity, and key laboratory data.

HYDROchlorothiazide versus placebo to PROTECT polycystic kidney disease patients and improve their quality of life: study protocol and rationale for the HYDRO-PROTECT randomized controlled trial

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) leads to progressive renal cyst formation and loss of kidney function in most patients. Vasopressin 2 receptor antagonists (V2RA) like tolvaptan are currently the only available renoprotective agents for rapidly progressive ADPKD. However, aquaretic side effects substantially limit their tolerability and therapeutic potential. In a preliminary clinical study, the addition of hydrochlorothiazide (HCT) to tolvaptan decreased 24-h urinary volume and appeared to increase renoprotective efficacy. The HYDRO-PROTECT study will investigate the long-term effect of co-treatment with HCT on tolvaptan efficacy (rate of kidney function decline) and tolerability (aquaresis and quality of life) in patients with ADPKD.

METHODS

The HYDRO-PROTECT study is an investigator-initiated, multicenter, double-blind, placebo-controlled, randomized clinical trial. The study is powered to enroll 300 rapidly progressive patients with ADPKD aged ≥ 18 years, with an eGFR of > 25 mL/min/1.73 m2, and on stable treatment with the highest tolerated dose of tolvaptan in routine clinical care. Patients will be randomly assigned (1:1) to daily oral HCT 25 mg or matching placebo treatment for 156 weeks, in addition to standard care.

OUTCOMES

The primary study outcome is the rate of kidney function decline (expressed as eGFR slope, in mL/min/1.73 m2 per year) in HCT versus placebo-treated patients, calculated by linear mixed model analysis using all available creatinine values from week 12 until the end of treatment. Secondary outcomes include changes in quality-of-life questionnaire scores (TIPS, ADPKD-UIS, EQ-5D-5L, SF-12) and changes in 24-h urine volume.

CONCLUSION

The HYDRO-PROTECT study will demonstrate whether co-treatment with HCT can improve the renoprotective efficacy and tolerability of tolvaptan in patients with ADPKD.

Prenatal diagnosis of polycystic kidney caused by biallelic hypomorphic variants in the PKD1 gene

Heterozygous loss-of-function variants in the PKD1 gene are commonly associated with adult-onset autosomal dominant polycystic kidney disease (ADPKD), where the formation of renal cysts depends on the dosage of the PKD1 gene. Biallelic null PKD1 variants are not viable, but biallelic hypomorphic variants could lead to early-onset PKD. We report a non-consanguineous Chinese family with recurrent fetal polycystic kidney and negative findings in the coding region of the PKHD1 gene or chromosomal microarray analysis. Trio exome analysis revealed compound heterozygous variants of uncertain significance in the PKD1 gene in the index pregnancy: a novel paternally inherited c.7863 + 5G > C and a maternally inherited c.9739C > T, p.(Arg3247Cys). Segregation analysis through long-range PCR followed by nested PCR and Sanger sequencing confirmed another affected fetus had both variants, while the other two normal siblings and the parents carried either variant. Thus, these two variants, both of which were hypomorphic as opposed to null variants, co-segregated with prenatal onset polycystic kidney disease in this family. Functional studies are needed to further determine the impact of these two variants. Our findings highlight the biallelic inheritance of hypomorphic PKD1 variants causing prenatal onset polycystic kidney disease, which provides a better understanding of phenotype-genotype correlation and valuable information for reproductive counseling.

Laparoscopic Nephrectomy Via the Retroperitoneal Approach for Autosomal Dominant Polycystic Kidney Disease After Renal Transplant: A Case Report

We report a case of laparoscopic nephrectomy via the retroperitoneal approach for autosomal dominant polycystic kidney disease after renal transplant. A 54-year-old male patient with end-stage renal failure because of autosomal dominant polycystic kidney disease underwent a living donor renal transplant and right nephrectomy via open surgery through a median abdominal incision 5 years previously. However, the left kidney gradually became enlarged. We performed laparoscopic left nephrectomy via the retroperitoneal approach. After dissecting the renal vessels, we performed cyst puncture and aspiration to decrease the kidney volume. The patient's symptoms improved after operation. Laparoscopic nephrectomy for enlarged kidneys with multiple cysts can be safely performed, and the retroperitoneal approach can be preferred if the patient has a history of abdominal surgery or an enlarged polycystic kidney.

External carotid artery pseudoaneurysm rupture in a patient with polycystic kidney disease: Case report and review of literature

BACKGROUND

Vascular abnormalities, including dissections and aneurysms, can be found in patients with autosomal dominant kidney disease (ADPKD). While intracranial aneurysms have been reported in 10%-25% of ADPCKD, occurrences at other locations are exceedingly rare.

METHOD

This is a first case report of a patient with ADPCKD who presented with a rupture of the left external carotid artery pseudoaneurysm.

CONCLUSION

Rupture of a carotid artery aneurysm is rare with potentially high morbidity. An endovascular and surgical approach are effective strategies for successful management that depends on etiology, location, and surgeon experience.

Molecular diagnostic results of a nephropathy gene panel in patients with suspected hereditary kidney disease

OBJECTIVE

Clinical diagnosis of hereditary kidney disease can be difficult because of its rarity and severe phenotypic variability. Identifying mutated causative genes can provide diagnostic and prognostic information. In this study, we report the clinical application and outcome of a next-generation sequencing-based, targeted multi-gene panel test for the genetic diagnosis of patients with hereditary kidney disease.

METHODS

A total of 145 patients evaluated for hereditary kidney disease who underwent a nephropathy panel with 44 different genes were retrospectively reviewed and included in the study.

RESULTS

Genetic diagnosis of other hereditary kidney diseases, particularly autosomal dominant polycystic kidney disease, was made in 48% of patients. The nephropathy panel changed the preliminary diagnosis in 6% of patients. The variants in 18 (12%) patients had not been previously reported in the literature.

CONCLUSION

This study demonstrates the utility of the nephropathy panel in identifying patients diagnosed with hereditary kidney disease who are referred for genetic testing. A contribution was made to the variant spectrum of genes associated with hereditary kidney disease.

The VUS Challenge in Cystic Kidney Disease: A Case-Based Review

Genetic testing in nephrology is becoming increasingly important to diagnose patients and to provide appropriate care. This is especially true for autosomal dominant polycystic kidney disease (ADPKD) because this is a common cause of kidney failure and genetically complex. In addition to the major genes, PKD1 and PKD2 , there are at least six minor loci, and phenotypic, and in some cases, genetic overlap with other cystic disorders. Targeted next-generation sequencing, a low-cost, high-throughput technique, has made routine genetic testing viable in nephrology clinics. Appropriate pre- and post-testing genetic counseling is essential to the testing process. Carefully assessing variants is also critical, with the genetic report classifying variants in accordance with American College of Medical Genetics and Genomics guidelines. However, variant of uncertain significance (VUSs) may pose a significant challenge for the ordering clinician. In ADPKD, and particularly within PKD1 , there is high allelic heterogeneity; no single variant is present in more than 2% of families. The Mayo/Polycystic Kidney Disease Foundation variant database, a research tool, is the best current database of PKD1 and PKD2 variants containing over 2300 variants identified in individuals with polycystic kidney disease, but novel variants are often identified. In patients with a high pretest probability of ADPKD on the basis of clinical criteria, but no finding of a pathogenic (P) or likely pathogenic (LP) variant in a cystic kidney gene, additional evaluation of cystic gene VUS can be helpful. In this case-based review, we propose an algorithm for the assessment of such variants in a clinical setting and show how some can be reassigned to a diagnostic grouping. When assessing the relevance of a VUS, we consider both patient/family-specific and allele-related factors using population and variant databases and available prediction tools, as well as genetic expertise. This analysis plus further family studies can aid in making a genetic diagnosis.

Molecular genetic diagnosis of kidney ciliopathies: Lessons from interpreting genomic sequencing data and the requirement for accurate phenotypic data

INTRODUCTION

Massively parallel sequencing (MPS) techniques have made a major impact on the identification of the genetic basis of inherited kidney diseases such as the ciliopathy autosomal dominant polycystic kidney disease (ADPKD). Great care must be taken when analysing MPS data in isolation from accurate phenotypic information, as this can cause misdiagnosis.

METHODS

Here, we describe a family trio, recruited to the Genomics England 100,000 Genomes Project, labelled as having cystic kidney disease, who were genetically unsolved following routine data analysis pipelines. We performed a bespoke reanalysis of Whole Genome Sequencing (WGS) data and coupled this with revised phenotypic data and targeted PCR and Sanger sequencing to provide a precise molecular genetic diagnosis.

RESULTS

We detected a heterozygous PKD1 frameshift variant within the WGS data which segregated with the redefined ADPKD phenotypes. An additional heterozygous exon deletion in ALG8 was also found in affected and unaffected individuals, but its precise clinical significance remains unclear.

CONCLUSION

This case illustrates that reanalysis of WGS data in unsolved cases of cystic kidney disease is valuable. Clinical phenotypes must be reassessed as these may have been incorrectly recorded and evolve over time. Undertaking additional studies including genotype-phenotype correlation in wider family members provides useful diagnostic information.

DNAJB11 Mutation in ADPKD Patients: Clinical Characteristics in a Monocentric Cohort

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a late-onset cilia-related disorder, characterized by progressive cystic enlargement of the kidneys. It is genetically heterogeneous with PKD1 and PKD2 pathogenic variants identified in approximately 78% and 15% of families, respectively. More recently, additional ADPKD genes, such as DNAJB11, have been identified and included in the diagnostic routine test for renal cystic diseases. However, despite recent progress in ADPKD molecular approach, approximately ~7% of ADPKD-affected families remain genetically unresolved. We collected a cohort of 4 families from our center, harboring heterozygous variants in the DNAJB11 gene along with clinical and imaging findings consistent with previously reported features in DNAJB11 mutated patients. Mutations were identified as likely pathogenetic (LP) in three families and as variants of uncertain significance (VUS) in the remaining one. One patient underwent to kidney biopsy and showed a prevalence of interstitial fibrosis that could be observed in ~60% of the sample. The presence in the four families from our cohort of ADPKD characteristics together with ADTKD features, such as hyperuricemia, diabetes, and chronic interstitial fibrosis, supports the definition of DNAJB11 phenotype as an overlap disease between these two entities, as originally suggested by the literature.

Beyond Loss of Kidney Function: Patient Care in Autosomal Dominant Polycystic Kidney Disease

Patients with autosomal dominant polycystic kidney disease benefit from specialized care over their lifetimes, starting with diagnosis of the condition with ongoing discussion of both the renal course and extra-renal issues. Both renal and extra-renal issues may continue to cause major morbidity even after successful kidney transplant or initiation of RRT, and extra-renal disease aspects should always be considered as part of routine management. In this review, we will focus on updates in pain/depression screening, cardiac manifestations, liver and pancreatic cysts, kidney stone management, and genetic counseling. In some instances, we have shared our current clinical practice rather than an evidence-based guideline. We anticipate more standardization of care after the release of the Kidney Disease Improving Global Outcomes guidelines for management in autosomal dominant polycystic kidney disease later this year.

OGM and WES identifies translocation breakpoints in PKD1 gene in an polycystic kidney patient and healthy baby delivered using PGT

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common autosomal dominant genetic diseases. Whole exome sequencing (WES) is a routine tool for diagnostic confirmation of genetic diseases, and it is usually performed to confirm the clinical diagnosis in ADPKD. Reciprocal translocation is the most common chromosomal structural abnormalities and most of its carriers have normal phenotypes until they are encountered infertility problems in adulthood. However, for the polycystic kidney disease caused by abnormal chromosome structure, WES is difficult to achieve the purpose of gene diagnosis.

METHODS

ADPKD-related genes were detected by WES; Chromosomal karyotyping and Optical Genome Mapping (OGM) were used to detect structural variant; The genomic break-point locations and the abnormal splicing were detected by reverse transcription-PCR and Sanger sequencing; The karyomapping gene chip and Next-Generation Sequencing (NGS) were performed to screen aneuploidy and to distinguish the non-carrier embryos from the carrier embryos.

RESULTS

No pathogenic variant was found after the first round of WES analysis. Karyotyping data showed 46, XX, t (16; 17) (p13.3; q21.3). With the help of OGM, the translocation breakpoint on chromosome 16 was located within the PKD1 gene. With re-analysis of WES raw data, the breakpoint of translocation was verified to be located at the c.10618 + 3 of PKD1 gene. Based on this molecular diagnosis, a non-carrier embryo was selected out from three blastocysts. With preimplantation genetic testing (PGT) after in vitro fertilization (IVF), it was then transferred into uterus. With confirmation by prenatal and postnatal testing, the pedigree delivered a healthy baby.

CONCLUSION

We identified a case of ADPKD caused by balanced translocation and assisted the patient to have a healthy child. When the phenotype was closely related with a monogenic disease and the WES analysis was negative, chromosomal structural analysis would be recommended for further genetic diagnosis. Based on the precision diagnosis, preventing the recurrence of hereditary diseases in offspring would be reachable.

Cardiometabolic comorbidities in autosomal dominant polycystic kidney disease: a 16-year retrospective cohort study

BACKGROUND

Autosomal-dominant polycystic kidney disease (ADPKD) is the most prevalent hereditary kidney disease and the fourth leading cause of end-stage renal disease (ESRD) requiring renal replacement therapy (RRT). Nevertheless, there is a paucity of epidemiological research examining the risk factors and survival on RRT for ADPKD. Thus, we aimed to investigate the cumulative effects of cardiometabolic comorbidities, including hypertension (HTN), type 2 diabetes mellitus (DM), and dyslipidemia (DLP) to clinical outcomes in ADPKD.

METHODS

We identified 6,142 patients with ADPKD aged ≥ 20 years from 2000 to 2015 using a nationwide population-based database. HTN, DM, and DLP diagnoses before or at the time of ADPKD diagnosis and different combinations of the three diagnoses were used as the predictors for the outcomes. Survival analyses were used to estimate the adjusted mortality risk from cardiometabolic comorbidities and the risk for renal survival.

RESULTS

Patients with ADPKD who developed ESRD had the higher all-cause mortality (HR, 5.14; [95% CI: 3.88-6.80]). Patients with all three of the diseases had a significantly higher risk of entering ESRD (HR:4.15, [95% CI:3.27-5.27]), followed by those with HTN and DM (HR:3.62, [95% CI:2.82-4.65]), HTN and DLP (HR:3.54, [95% CI:2.91-4.31]), and HTN alone (HR:3.10, [95% CI:2.62-3.66]) compared with those without any three cardiometabolic comorbidities.

CONCLUSIONS

Our study discovered the cumulative effect of HTN, DM, and DLP on the risk of developing ESRD, which reinforces the urgency of proactive prevention of cardiometabolic comorbidities to improve renal outcomes and overall survival in ADPKD patients.

Double Heterozygous Pathogenic Variants in the LOX and PKD1 Genes in a 5-Year-Old Patient with Thoracic Aortic Aneurysm and Polycystic Kidney Disease

Familial thoracic aortic aneurysms and dissections may occur as an isolated hereditary trait or as part of connective tissue disorders with Mendelian inheritance, but severe cardiovascular disease in pediatric patients is extremely rare. There is growing knowledge on pathogenic variants causing the disease; however, much of the phenotypic variability and gene-gene interactions remain to be discovered. We present a case report of a 5.5-year-old girl with an aortic aneurysm and concomitant polycystic kidney disease. Whole exome sequencing was performed, followed by family screening by amplicon deep sequencing and diagnostic imaging studies. In the proband, two pathogenic variants were identified: p.Tyr257Ter in the LOX gene inherited from her mother, and p.Thr2977Ile in the PKD1 gene inherited from her father. All adult carriers of either of these variants showed symptoms of aortic disease. We conclude that the coexistence of two independent genetic variants in the proband may be the reason for an early onset of disease.

Public support for patients with intractable diseases in Japan: impact on clinical indicators from nationwide registries in patients with autosomal dominant polycystic kidney disease

BACKGROUND

Clinical practice guidelines recommend antihypertensive and tolvaptan therapies for patients with autosomal dominant polycystic kidney disease (ADPKD) in Japan. However, tolvaptan therapy may pose an economic burden. The Japanese Ministry of Health, Labour and Welfare supports patients with intractable diseases. This study aimed to confirm the impact of the intractable disease system in Japan on the clinical treatment of ADPKD.

METHODS

We analyzed the data of 3768 patients with ADPKD having a medical subsidy certificate from the Japanese Ministry of Health, Labour and Welfare in 2015-2016. The following quality indicators were use: the adherence rate to the 2014 clinical practice guideline for polycystic kidney disease (prescription rates of antihypertensive agents and tolvaptan in this cohort) and the number of Japanese patients with ADPKD nationwide started on renal replacement therapy in 2014 and 2020.

RESULTS

Compared with new applications from 2015 to 2016, the prescription rates of antihypertensives and tolvaptan for the indicated patients at the 2017 renewal application increased by 2.0% (odds ratio = 1.41, p = 0.008) and 47.4% (odds ratio = 10.1, p > 0.001), respectively. These quality indicators improved with antihypertensive treatment, especially in patients with chronic kidney disease stages 1-2 (odds ratio = 1.79, p = 0.013) and in those aged < 50 years (odds ratio = 1.70, p = 0.003). The number of patients with ADPKD who were started on renal replacement therapy in Japan decreased from 999 in 2014 to 884 in 2020 in the nationwide database (odds ratio = 0.83, p < 0.001).

CONCLUSIONS

The Japanese public intractable disease support system contributes to improvement of ADPKD treatment.

Factors Associated With the Development and Severity of Polycystic Liver in Patients With Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Factors related to the development and severity of polycystic liver disease (PLD) have not been well established. We aimed to evaluate the genetic and epidemiologic risk factors of PLD in patients with autosomal dominant polycystic kidney disease (ADPKD).

METHODS

Adult patients with inherited cystic kidney disease were enrolled from May 2019 to May 2021. Demographic, clinical, and laboratory data were collected at the initial study visit. The severity of PLD was graded based on the height-adjusted total liver volume: < 1,000 mL/m (Gr1), 1,000-1,800 mL/m (Gr2), and > 1,800 mL/m (Gr3). Targeted exome sequencing was done by a gene panel including 89 ciliopathy-related genes. We searched out the relative factors to the presence and the severity of PLD using logistic regression analysis.

RESULTS

Of 602 patients with typical ADPKD, 461 (76.6%) patients had PLD. The patients with PLD showed female predominance and a higher frequency of other ADPKD-related complications. The genetic variants with truncating mutation of PKD1 (PKD1-protein-truncating [PT]) or PKD2 commonly affected the development and severity of PLD. An older age, female sex, and higher kidney volume with Mayo classification 1C-1E was significantly associated with the development of PLD, but not with the severity of PLD. On the other hand, higher body mass index, lower hemoglobin, and higher alkaline phosphatase (ALP) were the significant risk factors of severe PLD (≥ Gr2).

CONCLUSION

Hepatic involvement in ADPKD could be related to kidney manifestations and genetic variants including PKD1-PT or PKD2. Monitoring hemoglobin and ALP and evaluating the genetic variants might help predict severe PLD.

TRIAL REGISTRATION

Clinical Research Information Service Identifier: KCT0005580.

A long-read sequencing and SNP haplotype-based novel preimplantation genetic testing method for female ADPKD patient with de novo PKD1 mutation

The autosomal dominant form of polycystic kidney disease (ADPKD) is the most common hereditary disease that causes late-onset renal cyst development and end-stage renal disease. Preimplantation genetic testing for monogenic disease (PGT-M) has emerged as an effective strategy to prevent pathogenic mutation transmission rely on SNP linkage analysis between pedigree members. Yet, it remains challenging to establish reliable PGT-M methods for ADPKD cases or other monogenic diseases with de novo mutations or without a family history. Here we reported the application of long-read sequencing for direct haplotyping in a female patient with de novo PKD1 c.11,526 G > C mutation and successfully established the high-risk haplotype. Together with targeted short-read sequencing of SNPs for the couple and embryos, the carrier status for embryos was identified. A healthy baby was born without the PKD1 pathogenic mutation. Our PGT-M strategy based on long-read sequencing for direct haplotyping combined with targeted SNP haplotype can be widely applied to other monogenic disease carriers with de novo mutation.

Pregnancy in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disorder occurring in approximately 1:1000 individuals. ADPKD is characterized by gradual cyst expansion and kidney enlargement and is a slowly progressive disorder where patients typically initiate renal replacement therapy in the sixth decade of life. The vast majority of women with ADPKD become pregnant in the third or fourth decade, often before knowing that they have ADPKD, in the setting of normal kidney function or chronic kidney disease Stage 1. In ADPKD, pregnancy outcomes for mother and baby differ from the general population, and long-term consequences of maternal complications from pregnancy are common in ADPKD. In the current era of genetic testing, options to consider pre-implantation genetic screening are becoming more available. This chapter will review renal physiologic and anatomic changes that occur in pregnancy, the potential impact of ADPKD on maternal and fetal outcomes, medical management during pregnancy, the impact of pregnancy on long-term outcomes in women with ADPKD, and options for families with ADPKD planning to undergo pregnancy with regard to genetic testing.

Low agreement between various eGFR formulae in pediatric and young adult ADPKD patients

BACKGROUND

Young autosomal dominant polycystic kidney disease (ADPKD) patients are becoming the new target population for the development of new treatment options. Determination of a reliable equation for estimated glomerular filtration rate (eGFR) from early stages is needed with the promising potential interventional therapies.

METHODS

Prospective and longitudinal study on a cohort of 68 genotyped ADPKD patients (age range 0-23 years) with long-term follow-up. Commonly used equations for eGFR were compared for their relative performance.

RESULTS

The revised Schwartz formula (CKiD) showed a highly significant decline in eGFR with aging (- 3.31 mL/min/1.73 m2/year, P < 0.0001). The recently updated equation by the Schwartz group (CKiDU25) showed a smaller (- 0.90 mL/min/1.73 m2/year) but significant (P = 0.001) decline in eGFR with aging and also showed a significant sex difference (P < 0.0001), not observed by the other equations. In contrast, the full age spectrum (FAS) equations (FAS-SCr, FAS-CysC, and the combined) showed no age and sex dependency. The prevalence of hyperfiltration is highly dependent on the formula used, and the highest prevalence was observed with the CKiD Equation (35%).

CONCLUSIONS

The most widely used methods to calculate eGFR in ADPKD children (CKiD and CKiDU25 equations) were associated with unexpected age or sex differences. The FAS equations were age- and sex-independent in our cohort. Hence, the switch from the CKiD to CKD-EPI equation at the transition from pediatric to adult care causes implausible jumps in eGFR, which could be misinterpreted. Having reliable methods to calculate eGFR is indispensable for clinical follow-up and clinical trials. A higher resolution version of the Graphical abstract is available as Supplementary information.

Dual diagnosis of autosomal dominant polycystic kidney disease and sickle cell disease in a teenage male

BACKGROUND

Sickle cell disease (SCD) and autosomal dominant polycystic kidney disease (ADPKD) are relatively common genetic conditions with considerable overlap in clinical presentation. In addition to similarities between the signs and symptoms in sickle cell nephropathy and ADPKD, more than half of SCD patients have kidney cysts. The co-occurrence of these two diseases has not been previously reported in the literature.

CASE DIAGNOSIS/TREATMENT

A 16-year-old Black male with SCD had bilateral kidney enlargement and multiple simple cysts on ultrasound. Although kidney cysts are significantly more common in individuals affected with SCD, genetic testing with a broad kidney gene panel was performed to explore the possible presence of another underlying genetic cause of his cysts, in addition to SCD. A dual diagnosis of SCD and ADPKD was made following the identification of two copies of the common pathogenic sickle cell HBB variant (c.20A > T, p.Glu7Val) and a pathogenic missense variant in PKD1 (c.8311G > A, p.Glu2771Lys).

CONCLUSIONS

SCD and ADPKD differ in pathophysiological mechanisms and treatment regimens. As such, it will be paramount for this teenager to be closely monitored for signs of diminished kidney function and to be co-managed as he transitions to adult care to ensure proper treatment and management. Early identification of individuals with both SCD and a co-occurring condition is crucial to ensuring proper clinical management. Furthermore, identifying and reporting additional patients with SCD and ADPKD dual diagnoses will help us to understand the co-occurring disease course and optimal treatments.

Renin-angiotensin system activation: may it increase frequency of obstructive sleep apnea in patients with autosomal dominant polycystic kidney disease?

PURPOSE

Renin-angiotensin system (RAS) hyperactivity is a common entity in both autosomal dominant polycystic kidney disease (ADPKD) and obstructive sleep apnea (OSA). We aimed to investigate the frequency of OSA in adults with ADPKD either with stages 3-4 or stages 1-2 chronic kidney disease (CKD) and evaluate the effect of RAS blockade on OSA in these patients.

METHODS

This is a comparative, prospective, two-center clinical study. Eligible patients with ADPKD were enrolled in a polysomnography (PSG) study. Presence of OSA in patients with ADPKD was compared with individuals who underwent polisomnography study due to OSA symptoms. A subgroup analysis was performed in terms of the presence of OSA in ADPKD with eGFR values lower or higher than 60 ml/min/1.73 m2 (stages 3-4 and stages 1-2 CKD, respectively).

RESULTS

Frequency of OSA (65%) was higher than in the general population and similar between the two groups (p = 0.367). Patients with ADPKD and eGFR ≥ 60 ml/min/1.73 m2 presented a similar frequency of OSA to the control group (p = 0.759). However, OSA was significantly more frequent in ADPKD with eGFR < 60 ml/min/1.73 m2 (p = 0.018). Subgroup analysis revealed that presence of OSA also was significantly higher in ADPKD with lower eGFR levels (eGFR < 60 ml/min/1.73 m2 and eGFR > 60 ml/min/1.73 m2) 14/17 (82%) and 12/23 (52%), respectively (p: 0.048).

CONCLUSION

As kidney disease progresses, uremia and related factors of renal failure rather than RAS activation seem to play a more important role for the development of OSA in patients with ADPKD.

Autosomal dominant polycystic kidney disease in Colombia

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic cause of chronic kidney disease (CKD) that requires dialysis. Knowing geographical clusters can be critical for early diagnosis, progression control, and genetic counseling. The objective was to establish the prevalence, geographic location, and ethnic groups of patients with ADPKD who underwent dialysis or kidney transplant in Colombia between 2015 and 2019.

METHODS

We did a cross-sectional study with data from the National Registry of Chronic Kidney Disease (NRCKD) managed by the High-Cost Diseases Fund (Cuenta de Alto Costo [CAC] in Spanish) between July 1, 2015, and June 30, 2019. We included Colombian population with CKD with or without renal replacement therapy (RRT) due to ADPKD. Crude and adjusted prevalence rates were estimated by state and city.

RESULTS

3,339 patients with ADPKD were included, period prevalence was 9.81 per 100,000 population; there were 4.35 cases of RRT per 100,000 population, mean age of 52.58 years (± 13.21), and 52.78% women. Seventy-six patients were Afro-Colombians, six were indigenous, and one Roma people. A total of 46.07% began scheduled dialysis. The highest adjusted prevalence rate was in Valle del Cauca (6.55 cases per 100,000 population), followed by Risaralda, and La Guajira. Regarding cities, Cali had the highest prevalence rate (9.38 cases per 100,000 population), followed by Pasto, Medellin, and Bucaramanga.

CONCLUSIONS

ADPKD prevalence is lower compared to Europe and US; some states with higher prevalence could be objective to genetic prevalence study.

Cystic Kidney Diseases in Children and Adults: Differences and Gaps in Clinical Management

Cystic kidney diseases, when broadly defined, have a wide differential diagnosis extending from recessive diseases with a prenatal or pediatric diagnosis, to the most common autosomal-dominant polycystic kidney disease primarily affecting adults, and several other genetic or acquired etiologies that can manifest with kidney cysts. The most likely diagnoses to consider when assessing a patient with cystic kidney disease differ depending on family history, age stratum, radiologic characteristics, and extrarenal features. Accurate identification of the underlying condition is crucial to estimate the prognosis and initiate the appropriate management, identification of extrarenal manifestations, and counseling on recurrence risk in future pregnancies. There are significant differences in the clinical approach to investigating and managing kidney cysts in children compared with adults. Next-generation sequencing has revolutionized the diagnosis of inherited disorders of the kidney, despite limitations in access and challenges in interpreting the data. Disease-modifying treatments are lacking in the majority of kidney cystic diseases. For adults with rapid progressive autosomal-dominant polycystic kidney disease, tolvaptan (V2-receptor antagonist) has been approved to slow the rate of decline in kidney function. In this article, we examine the differences in the differential diagnosis and clinical management of cystic kidney disease in children versus adults, and we highlight the progress in molecular diagnostics and therapeutics, as well as some of the gaps meriting further attention.

An update on treatments for autosomal dominant polycystic kidney disease

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) is less common than primary hypertension or diabetes but should be considered as a possible cause of end-stage renal disease, especially in young patients without comorbidities. Because of ADPKD's nonspecific symptoms, the diagnosis, treatment, and pertinent patient education may be delayed. This article describes ADPKD and its management, including tolvaptan, a new treatment with the potential to reduce or delay morbidity. However, only a subset of patients qualifies for this expensive treatment.

Metabolomic profiling to identify early urinary biomarkers and metabolic pathway alterations in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the formation of numerous fluid-filled cysts that lead to progressive loss of functional nephrons. Currently, there is an unmet need for diagnostic and prognostic indicators of early stages of the disease. Metabolites were extracted from the urine of patients with early-stage ADPKD (n = 48 study participants) and age- and sex-matched normal controls (n = 47) and analyzed by liquid chromatography-mass spectrometry. Orthogonal partial least squares-discriminant analysis was used to generate a global metabolomic profile of early ADPKD for the identification of metabolic pathway alterations and discriminatory metabolites as candidates of diagnostic and prognostic biomarkers. The global metabolomic profile exhibited alterations in steroid hormone biosynthesis and metabolism, fatty acid metabolism, pyruvate metabolism, amino acid metabolism, and the urea cycle. A panel of 46 metabolite features was identified as candidate diagnostic biomarkers. Notable putative identities of candidate diagnostic biomarkers for early detection include creatinine, cAMP, deoxycytidine monophosphate, various androgens (testosterone; 5-α-androstane-3,17,dione; trans-dehydroandrosterone), betaine aldehyde, phosphoric acid, choline, 18-hydroxycorticosterone, and cortisol. Metabolic pathways associated with variable rates of disease progression included steroid hormone biosynthesis and metabolism, vitamin D3 metabolism, fatty acid metabolism, the pentose phosphate pathway, tricarboxylic acid cycle, amino acid metabolism, sialic acid metabolism, and chondroitin sulfate and heparin sulfate degradation. A panel of 41 metabolite features was identified as candidate prognostic biomarkers. Notable putative identities of candidate prognostic biomarkers include ethanolamine, C20:4 anandamide phosphate, progesterone, various androgens (5-α-dihydrotestosterone, androsterone, etiocholanolone, and epiandrosterone), betaine aldehyde, inflammatory lipids (eicosapentaenoic acid, linoleic acid, and stearolic acid), and choline. Our exploratory data support metabolic reprogramming in early ADPKD and demonstrate the ability of liquid chromatography-mass spectrometry-based global metabolomic profiling to detect metabolic pathway alterations as new therapeutic targets and biomarkers for early diagnosis and tracking disease progression of ADPKD.NEW & NOTEWORTHY To our knowledge, this study is the first to generate urinary global metabolomic profiles from individuals with early-stage ADPKD with preserved renal function for biomarker discovery. The exploratory dataset reveals metabolic pathway alterations that may be responsible for early cystogenesis and rapid disease progression and may be potential therapeutic targets and pathway sources for candidate biomarkers. From these results, we generated a panel of candidate diagnostic and prognostic biomarkers of early-stage ADPKD for future validation.

Blocker displacement amplification-based genetic diagnosis for autosomal dominant polycystic kidney disease and the clinical outcomes of preimplantation genetic testing

OBJECTIVE

Given that the molecular diagnosis of autosomal dominant polycystic kidney disease (ADPKD) is complicated, we aim to apply blocker displacement amplification (BDA) on the mutational screening of PKD1 and PKD2.

METHODS

A total of 35 unrelated families with ADPKD were recruited from the Center for Reproductive Medicine, Women and Children's Hospital of Chongqing Medical University (Chongqing, China), from October 2018 to October 2021. Long-range PCR followed by next-generation sequencing were applied for resequencing of PKD1 and PKD2, and the putatively disease-causative variants were verified with BDA. The effects of ADPKD on male and female infertility and the factors influencing the clinical outcomes of preimplantation genetic testing (PGT) for ADPKD were investigated.

RESULTS

A total of 26 PKD1 variants and 5 PKD2 variants were identified, of which 13 were newly discovered. The BDA system worked effectively for eliminating the interference of pseudogenes in genetic testing of PKD1 (1-33 exons) with different concentrations of genome DNA. The females with ADPKD have no specific infertility factors, while 68.2% of the affected men were with abnormal sperm concentration and/or motility with an indefinite genotype-phenotype relationship. As for PGT, the fertilization rate of couples with the male partner having ADPKD was relatively lower compared to those with the female partner being affected. The ADPKD patients receiving PGT usually achieved high rates of live births.

CONCLUSION

These findings expanded the variant spectrum of PKD genes and emphasized the application prospect of blocker displacement amplification on PKD1-related genetic diagnosis.

Individuals heterozygous for ALG8 protein-truncating variants are at increased risk of a mild cystic kidney disease

ALG8 protein-truncating variants (PTVs) have previously been described in patients with polycystic liver disease and in some cases cystic kidney disease. Given a lack of well-controlled studies, we determined whether individuals heterozygous for ALG8 PTVs are at increased risk of cystic kidney disease in a large, unselected health system-based observational cohort linked to electronic health records in Pennsylvania (Geisinger-Regeneron DiscovEHR MyCode study). Out of 174,172 patients, 236 were identified with ALG8 PTVs. Using ICD-based outcomes, patients with these variants were significantly at increased risk of having any kidney/liver cyst diagnosis (Odds Ratio 2.42, 95% confidence interval: 1.53-3.85), cystic kidney disease (3.03, 1.26-7.31), and nephrolithiasis (1.89, 1.96-2.97). To confirm this finding, blinded radiology review of computed tomography and magnetic resonance imaging studies was completed in a matched cohort of 52 thirty-plus year old ALG8 PTV heterozygotes and related non-heterozygotes. ALG8 PTV heterozygotes were significantly more likely to have cystic kidney disease, defined as four or more kidney cysts (57.7% vs. 7.7%), or bilateral kidney cysts (69.2% vs. 15.4%), but not one or more liver cyst (11.5% vs. 7.7%). In publicly available UK Biobank data, ALG8 PTV heterozygotes were at significantly increased risk of ICD code N28 (other disorders of kidney/ureter) (3.85% vs. 1.33%). ALG8 PTVs were not associated with chronic kidney disease or kidney failure in the MyCode study or the UK Biobank data. Thus, PTVs in ALG8 result in increased risk of a mild cystic kidney disease phenotype.

Hypomorphic PKD1 Alleles Impact Disease Variability in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) manifesting earlier than expected on the basis of family history can identify clinically tolerant PKD1 alleles with reduced expression. Hypomorphic PKD1 alleles can cause mild kidney disease or liver cysts in the absence of clinically manifest kidney involvement. The presented data highlight pleiotropic ADPKD clinical presentations and varying severity of kidney disease from PKD1 allele combinations.

Development of a Patient-Reported Outcomes Tool to Assess Pain and Discomfort in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Pain has been identified as a core outcome for individuals with autosomal dominant polycystic kidney disease (ADPKD), but no disease-specific pain assessment has been developed using current development methodology for patient-reported outcomes (PRO) instruments. We developed and validated an ADPKD-specific pain questionnaire: the ADPKD Pain and Discomfort Scale (ADPKD-PDS).

METHODS

Conceptual underpinnings were drawn from literature review, concept elicitation, expert consultation, and measurement performance. In the qualitative analysis phase, concepts were elicited from focus groups of adults with ADPKD, and the resulting draft instrument was refined using cognitive debriefing interviews with individuals with ADPKD. For quantitative analysis, adults with ADPKD completed the draft instrument and other PRO tools in an online survey, and a follow-up survey was conducted 3-4 weeks later. Survey responses were analyzed for item-level descriptive statistics, latent model fit statistics, item discrimination, item- and domain-level psychometric statistics, test-retest reliability, responsiveness to change, and convergent validity.

RESULTS

In the qualitative phase, 46 focus groups were conducted in 18 countries with 293 participants. Focus groups described three conceptually distinct types of ADPKD-related pain and discomfort (dull kidney pain, sharp kidney pain, and fullness/discomfort). In the quantitative phase, 298 adults with ADPKD completed the online survey, and 108 participants completed the follow-up survey. After iterative refinement of the instrument, latent variable measurement models showed very good fit (comparative fit and nonnormed fit indices both 0.99), as did item- and domain-level psychometric characteristics. The final ADPKD-PDS contains 20 items assessing pain severity and interference with activities over a 7-day recall period.

CONCLUSIONS

The ADPKD-PDS is the first validated tool for systematically assessing pain and discomfort in ADPKD.

Delayed diagnosis of bladder cancer in a patient with autosomal dominant polycystic kidney disease

ABSTRACT

Approximately 50% of autosomal dominant polycystic kidney disease (ADPKD) patients have gross hematuria, but few cases of bladder cancer complications are known. We report a case of a 49-year-old female ADPKD patient with bladder cancer, who was presented to our hospital 4 months after the onset of gross hematuria. A computed tomography (CT) scan showed a bladder mass, enlarged pelvic and left inguinal lymph nodes, multiple liver cysts, and a polycystic kidney. Based on family history, CT scan results, and lymph node biopsy, we diagnosed the patient with uroplakin III-negative bladder cancer with squamous metaplasia and ADPKD. The patient was treated with systemic chemotherapy but died 2 months after the definitive diagnosis. The delayed diagnosis was disastrous, and malignancy should be considered in the differential diagnosis when symptoms suggestive of malignancy such as hematuria appear. Particularly, uroplakin III-negative advanced bladder cancer has a poor prognosis and requires early diagnosis and treatment.

Considerations for genetic testing in individuals with autosomal dominant polycystic kidney disease

ABSTRACT

Autosomal dominant polycystic kidney disease (ADPKD) is a systemic, irreversible, genetic condition caused by mutations in the PKD1 and PKD2 genes, and the most common form of inherited kidney disease in the United States, affecting more than 600,000 individuals. Because the condition is autosomal dominant, there is a 50% chance that each child of an affected adult will also have the pathogenic genetic mutation. PKD1 mutation accounts for approximately 85% of ADPKD cases and is characterized by an earlier onset of disease with more rapid progression, whereas PKD2 mutation accounts for the remaining 15% of cases and is characterized by a less severe and less rapid disease course. Genetic testing is not consistently used in the management of individuals with ADPKD, although it can provide invaluable information regarding disease progression and prognosis. Genetic data are necessary to effectively communicate disease progression with patients, use current prognostic calculators, and play a role in family planning. Increasing clinician knowledge in primary care and nephrology providers will contribute to improved care for individuals affected by ADPKD.

Hereditary thrombotic thrombocytopenic purpura (TTP) with co-occurring autosomal dominant polycystic kidney disease (ADPKD)

Hereditary thrombotic thrombocytopenic purpura (TTP) and autosomal dominant polycystic kidney disease (ADPKD) are two distinct genetic diseases that may affect the kidneys through different mechanisms. ADPKD is a common genetic disorder that leads to exponential formation and growth of cysts replacing all segments of nephrons. Hereditary TTP is a rare autosomal recessive disorder that leads to the disseminated formation of arteriolar platelet-rich thrombi, which produce manifestations of various organs dysfunction. We present a case of a pregnant female with hereditary TTP co-occurring with ADPKD. To our knowledge, this is the first case in the literature describing the co-occurrence of ADPKD and hereditary TTP. We aim to describe the clinical course including the renal and the pregnancy outcomes, describe the consanguinity and family history, and try to explain the potential effect of one disease on the clinical course of the other.

[Analysis of PDK1 gene variants and prenatal diagnosis for eight pedigrees affected with autosomal dominant polycystic kidney disease]

OBJECTIVE

To detect potential variants in eight Chinese pedigrees affected with autosomal dominant polycystic kidney disease (ADPKD) and provide prenatal diagnosis for two of them.

METHODS

Whole exome sequencing and high-throughput sequencing were carried out to detect variants of PKD1 and PKD2 genes in the probands. Sanger sequencing was used to validate the variants, and their pathogenicity was predicted by searching the ADPKD and protein variation databases.

RESULTS

Eight PKD1 variants were detected, which have included five nonsense mutations and three missense mutations. Among these, four nonsense variants (PKD1: c.7555C>T, c.7288C>T, c.4957C>T, c.11423G>A) were known to be pathogenic, whilst one missense variant (PKD1: c.2180T>G) was classified as likely pathogenic. Three novel variants were detected, which included c.6781G>T (p.Glu2261*), c.109T>G (p.Cys37Gly) and c.8495A>G (p.Asn2832Ser). Prenatal testing showed that the fetus of one family has carried the same mutation as the proband, while the fetus of another family did not.

CONCLUSION

PKD1 variants, including three novel variants, have been identified in the eight pedigrees affected with ADPKD. Based on these results, prenatal diagnosis and genetic counseling have been provided.

Targeted Next Generation Sequencing Revealed Novel Variants in the PKD1 and PKD2 Genes of Iranian Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD), one of the common inherited disorders in humans, is characterized by the development and enlargement of renal cysts, often leading to end-stage renal disease (ESRD). In this study, Iranian ADPKD families were subjected to high-throughput DNA sequencing to find potential causative variants facilitating the way toward risk assessment and targeted therapy.

METHODS

Our protocol was based on the targeted next generation sequencing (NGS) panel previously developed in our center comprising 12 genes involved in PKD. This panel has been applied to investigate the genetic causes of 32 patients with a clinical suspicion of ADPKD.

RESULTS

We identified a total of 31 variants for 32 individuals, two of which were each detected in two individuals. Twenty-seven out of 31 detected variants were interpreted as pathogenic/likely pathogenic and the remaining 4 of uncertain significance with a molecular diagnostic success rate of 87.5%. Among these variants, 25 PKD1/2 pathogenic/likely pathogenic variants were detected in 32 index patients (78.1%), and variants of uncertain significance in four individuals (12.5% in PKD1/2). The majority of variants was identified in PKD1 (74.2%). Autosomal recessive PKD was identified in one patient, indicating the similarities between recessive and dominant PKD. In concordance with earlier studies, this biallelic PKD1 variant, p.Arg3277Cys, leads to rapidly progressive and severe disease with very early-onset ADPKD.

CONCLUSION

Our findings suggest that targeted gene panel sequencing is expected to be the method of choice to improve diagnostic and prognostic accuracy in PKD patients with heterogeneity in genetic background.

Design and Basic Characteristics of a National Patient-Powered Registry in ADPKD

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of inherited kidney disease worldwide. Over the past five years, the therapeutic pipeline for ADPKD has expanded, leading to a growing need for patient enrollment in clinical trials and improved understanding of patient-centered outcomes that can be used in trial design. To advance these goals, the Polycystic Kidney Disease Foundation (PKDF) established a national web-based ADPKD Registry.

METHODS

The ADPKD Registry is hosted on a secure, HIPAA-compliant, online platform (IQVIA, oc-meridian.com/pkdcure). Participants are consented through the online system and complete a series of modules. The Core Questionnaire includes patient-reported diagnosis, latest creatinine values, and comorbidities. Additional modules include surveys of family history, diet, quality of life, extrarenal manifestations, and attitudes surrounding research participation.

RESULTS

As of October 2021, 1563 ADPKD patients across the United States have registered and completed the Core Questionnaire. Participants have a median age of 44 years and are 72% women, 93% White, with 4% self-identifying as Hispanic/Latino and 2% as Black. All CKD stages are present, including post kidney transplant. To date, seven clinical studies have used the Registry as a recruitment tool. Additionally, quality-of-life burden scores revealed a correlation with disease stage as determined by kidney function.

CONCLUSIONS

The Registry described here is the only one of its kind and is a valuable longitudinal research tool encompassing all stages of ADPKD. The registry will allow investigators to pursue a range of research questions related to the management of ADPKD, including definition of health-related quality of life (HRQoL) outcomes and recruitment for a variety of observational and therapeutic clinical protocols.

[Analysis of PKD1 gene mutation in a pedigree affected with autosomal dominant polycystic kidney disease]

Objective: To analyze the clinical phenotype and detect the pathogenic gene in a Chinese pedigree with autosomal dominant polycystic kidney disease(ADPKD). Methods: The proband of this study was hospitalized in Dongguan City People's Hospital on October 10, 2017, due to "left maxillary apical cyst". Clinical phenotypes were noted, imaging examinations and determination of biochemical indicators were carried out for the clinical diagnosis of the proband. Genomic DNA was extracted from peripheral venous blood. Whole-exome genotyping of the proband was performed with the next generation sequencing technology, and the candidate mutation site of the patient and his family members was verified by PCR and Sanger sequencing technology. The mutation site was further screened in 150 unrelated healthy Chinese controls. Mutation frequency within human populations and bioinformatics analysis were predicted with softwares including ExAC, dbSNP, HGMD, 1000 genomes, ClinVar, PKDB, Mutation Taster and PhyloP. Results: The proband, a 46-year-old male, was diagnosed with hypertension, positive urine occult blood and elevated blood creatinine. B-ultrasound and CT examinations showed that he had bilateral polycystic kidney with left kidney stones and polycystic liver. The gene analysis showed that the c.11017-10C>A heterozygous splice mutation in PKD1 gene was identified in the proband, his second younger brother, younger sister, daughter and niece, but absent in 150 healthy controls. Bioinformatics analysis showed it has been reported in the dbSNP, ClinVar, HGMD, PKDB and Mutation Taster databases. Some databases predicted it has a harmful function for probably leading to production of a truncated polycystin1(PC1) protein. Conclusion: c.11017-10C>A underlies the Chinese ADPKD pedigree and expands mutation spectrum of PKD1.

Delay in funding of tolvaptan for polycystic kidney disease in Aotearoa New Zealand

Autosomal dominant polycystic kidney disease (ADPKD) is the fifth most common cause of end stage kidney disease (ESKD) in Aotearoa New Zealand. Identification of two genes, PCKD1 and PCKD2, which cause the majority of this disease, has played a key role in the development of DNA-sequence molecular diagnostics. ADPKD is characterised by the formation and growth of multiple cysts within the kidney, with some but not all patients progressing to ESKD. The diagnosis of ADPKD is based on the presence of family history, and radiological imaging although increasingly genetic testing is being used for screening and diagnosis. Once diagnosed, standard management of ADPKD includes laboratory monitoring of chronic kidney disease (CKD) parameters, lowering of blood pressure, and a high fluid intake. Over the last decade much research has been undertaken for targeted therapies for ADPKD; however, despite funding of these medications overseas since May 2015, and applications to Te Pātaka Whaioranga, The Pharmaceutical Management Agency (PHARMAC), these therapies remain unavailable to New Zealanders resulting in an increased burden of disease to individuals and the whānau and financial cost to the health system.

Consensus document on autosomal dominant polycystic kindey disease from the Spanish Working Group on Inherited Kindey Diseases. Review 2020

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent cause of genetic renal disease and accounts for 6-10% of patients on kidney replacement therapy (KRT). Very few prospective, randomized trials or clinical studies address the diagnosis and management of this relatively frequent disorder. No clinical guidelines are available to date. This is a revised consensus statement from the previous 2014 version, presenting the recommendations of the Spanish Working Group on Inherited Kidney Diseases, which were agreed to following a literature search and discussions. Levels of evidence mostly are C and D according to the Centre for Evidence-Based Medicine (University of Oxford). The recommendations relate to, among other topics, the use of imaging and genetic diagnosis, management of hypertension, pain, cyst infections and bleeding, extra-renal involvement including polycystic liver disease and cranial aneurysms, management of chronic kidney disease (CKD) and KRT and management of children with ADPKD. Recommendations on specific ADPKD therapies are provided as well as the recommendation to assess rapid progression.

[ADPKD and intracranial aneurysms: indications for screening, follow-up and clinical management]

Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent hereditary nephropathy and is the fourth most common cause for end-stage renal disease in Europe. ADPKD is a systemic disease; besides the typical renal involvement, characterized by progressive cyst expansion leading to massive enlargement and distortion of the kidney architecture and, ultimately, to end-stage renal disease, multiple extrarenal manifestations can be observed included cysts in other organs, diverticulosis, cardiac valvulopathies, abdominal and inguinal hernias, vascular anomalies. The rupture of an intracranial aneurysm is one of the most serious complications in ADPKD patients. Aim of this review is to provide useful indications for the clinician to define the risk of intracranial aneurysms in ADPKD population, to identify screening criteria (which patients to screen, how often and with which diagnostic methods), to estimate the risk of rupture of intracranial aneurysms, which may require intervention.