Monkeys mutant for PKD1 recapitulate human autosomal dominant polycystic kidney disease

Anoctamin 1 induces calcium-activated chloride secretion and proliferation of renal cyst–forming epithelial cells

In vitro cyst formation of ADPKD cells.

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 or PKD2, which encode polycystin-1 and polycystin-2, respectively. Rodent models are available to study the pathogenesis of polycystic kidney disease (PKD) and for preclinical testing of potential therapies-either genetically engineered models carrying mutations in Pkd1 or Pkd2 or models of renal cystic disease that do not have mutations in these genes. The models are characterized by age at onset of disease, rate of disease progression, the affected nephron segment, the number of affected nephrons, synchronized or unsynchronized cyst formation and the extent of fibrosis and inflammation. Mouse models have provided valuable mechanistic insights into the pathogenesis of PKD; for example, mutated Pkd1 or Pkd2 cause renal cysts but additional factors are also required, and the rate of cyst formation is increased in the presence of renal injury. Animal studies have also revealed complex genetic and functional interactions among various genes and proteins associated with PKD. Here, we provide an update on the preclinical models commonly used to study the molecular pathogenesis of ADPKD and test potential therapeutic strategies. Progress made in understanding the pathophysiology of human ADPKD through these animal models is also discussed.

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 and PKD2, encoding polycystin-1 (PC1) and polycystin-2 (PC2), which are required for the regulation of the renal tubular diameter. Loss of polycystin function results in cyst formation. Atypical forms of ADPKD are caused by mutations in genes encoding endoplasmic reticulum (ER)-resident proteins through mechanisms that are not well understood. Here, we investigate the function of DNAJB11, an ER co-chaperone associated with atypical ADPKD. We generated mouse models with constitutive and conditional Dnajb11 inactivation and Dnajb11-deficient renal epithelial cells to investigate the mechanism underlying autosomal dominant inheritance, the specific cell types driving cyst formation, and molecular mechanisms underlying DNAJB11-dependent polycystic kidney disease. We show that biallelic loss of Dnajb11 causes cystic kidney disease and fibrosis, mirroring human disease characteristics. In contrast to classical ADPKD, cysts predominantly originate from proximal tubules. Cyst formation begins in utero and the timing of Dnajb11 inactivation strongly influences disease severity. Furthermore, we identify impaired PC1 cleavage as a potential mechanism underlying DNAJB11-dependent cyst formation. Proteomic analysis of Dnajb11- and Pkd1-deficient cells reveals common and distinct pathways and dysregulated proteins, providing a foundation to better understand phenotypic differences between different forms of ADPKD.

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic ciliopathy that causes adult-onset progressive renal failure. Inflammation and the resulting fibrosis play a crucial role in the pathogenesis. In recent years, an increasing number of inflammatory markers such as MCP-1 and TNF-α, that are associated with the development and progression of ADPKD have been identified. The objective of this study was to identify and evaluate potential proinflammatory biomarkers in patients with ADPKD from the German AD(H)PKD registry. In this exploratory pilot study, serum concentrations of IL-1β, IL-2, IL-6, IL-8, IL-10, IL-13, IFN-γ, MCP-1 and TNF-α were measured by multiplex immunoassay in 233 adults patients with ADPKD from the German AD(H)PKD registry and compared to an age- and sex-matched healthy control group (n = 30). IL-6, IL-8, MCP-1, TNF-α and IFN-γ concentrations were significantly higher in patients with ADPKD than in healthy controls. In addition, sex influenced the concentrations of MCP-1 and TNF-α in the ADPKD and control groups (MCP-1 male =134.8 pg/l, female=75.11pg/l; p = 0.0055; TNF-α male=26.22pg/l, female=21.08 pg/l; p = 0.0038). In conclusion, patients with ADPKD have significantly higher levels of IL-6, IL-8, MCP-1, TNF-α and IFN-γ compared to healthy individuals. These findings underline that inflammation may play a crucial role in the pathogenesis of ADPKD and may be a potential target, both as biomarkers and for therapeutic interventions.

Background: A significant phenotypical variability is observed in autosomal dominant polycystic kidney disease (ADPKD). The variability cannot be fully explained by the genetic heterogeneity of the disease. We examined the influence of G‐protein β3‐subunit C825T polymorphism and endothelial nitric oxide synthase Glu298Asp polymorphism on the progression of ADPKD towards end stage renal failure (ESRF). Methods: 306 ADPKD patients (pts) were analyzed; 261 pts (136 males, 125 females) with ESRF, with subgroup of 73 pts (44 males, 29 females) with ESRF before 45 years (rapid progressors), 46 pts (20 males, 26 females) with ESRF later than in 63 years (slow progressors) and 45 ADPKD pts (17 males, 28 females) in mean age 51 years with serum creatinine under 110 µmol/L (slow progressors) and 100 genetically unrelated healthy Czech subjects. DNA samples from collected blood were genotyped for G‐protein β3‐subunit C825T genotype in exon 10 and for endothelial nitric oxide synthase Glu298Asp genotype in exon 7. Results: The G‐protein β3‐subunit C825T genotype exhibited no significant differences among the groups of slow progressors (6.6% (6/91) TT, 54.9% (50/91) CT, 38.8% (35/91) CC), rapid progressors (9.6% (7/73) TT, 46.6% (34/73) CT, 43.8% (32/73) CC), ADPKD group with ESRF between 40–63 years (9.2% (13/142) TT, 50% (71/142) CT, 40.8% (58/142) CC) and control group (12% TT, 44% CT, 44% CC). When comparing the ages of ESRF of all patients with ESRF, we did not find significant differences in the ages: males TT—51.7 ± 8.8 years, CT—51.9 ± 10.3 years, CC—49.7 ± 10.2 years and females TT—56 ± 9.9 years, CT—53.2 ± 8.5 years, CC—53.9 ± 8.7 years. The endothelial nitric oxide synthase Glu298Asp and Asp29Asp genotypes were significantly more frequent in rapid progressors (9.6% (7/73) Asp/Asp, 39.7% (29/73) Asp/Glu, 50.7% (37/73) Glu/Glu) and in ADPKD group with ESRF between 40–63 years (11.3% (16/142) Asp/Asp, 41.5% (59/142) Asp/Glu, 47.2% (67/142) Glu/Glu) in comparison with slow progressors (8.8% (8/91) Asp/Asp, 24.2% (22/91) Asp/Glu, 67.0% (61/91) Glu/Glu) and with control group (8% Asp/Asp, 32% Asp/Glu, 60% Glu/Glu) (Chi‐square test, p < 0.05). Comparing the ages of ESRF of all patients with ESRF, we did not find significant differences in the ages in males with Asp/Asp—54.9 ± 10.4 years, Asp/Glu—50.2 ± 9.4 years, Glu/Glu—51.0 ± 10.4 years. We found out in homozygous Asp/Asp females significantly earlier onset of ESRF (49.2 ± 5.6 years) in comparison with heterozygous females (53.3 ± 7.2 years) and with Glu/Glu homozygous females (54.8 ± 9.7 years) (t‐test, p < 0.05). Conclusion: We excluded the significance of G‐protein β3‐subunit C825T polymorphism on the progression of ADPKD. We established the negative prognostic value of the carriers of Asp variant of eNOS polymorphism. Finding of new modifiers could have in future clinical consequences for ADPKD patients.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is caused by mutations in PKD1 or PKD2 and is the most common single-gene disorder resulting in kidney failure. Since deletion of either Pkd1 or Pkd2 in mice is embryonically lethal, conditional alleles have become indispensable tools for studying the pathobiology of ADPKD and for preclinical testing. The rapidity of cyst formation in Pkd1 conditional mice depends on the timing of gene inactivation, but this has never been systematically studied for Pkd2. Here, we characterize the kinetics of cystogenesis in a Pkd2 conditional mouse model and identify associated alterations in gene expression. Using a conditional mouse model, we inactivated Pkd2 at different postnatal stages and characterized the severity of cyst formation. Additionally, we performed RNA-sequencing analysis to identify gene expression changes associated with Pkd2 loss in males and females. There is a similar developmental switch in Pkd2 conditional mice with delayed cyst formation after Pkd2 inactivation at or beyond postnatal day 14. Like Pkd1 models, cystogenesis is associated with differential expression of genes involved in metabolism, cell proliferation, and immune response. We confirm that sex is a key modifier of ADPKD progression with differences in disease severity occurring in the context of significant transcriptional differences between males and females that are independent of the Pkd2 genotype. Pkd2 conditional mice are a useful model for understanding ADPKD pathogenesis and for testing therapeutics. Our data highlight the importance of sex as a biological variable that should be considered in any study design using orthologous mouse models with late Pkd2 inactivation.

The mechanisms contributing to progressive kidney damage in autosomal dominant polycystic kidney disease (ADPKD) remain unclear. Renal microvascular (MV) rarefaction plays an important role in kidney disease, but its natural history, underlying mechanisms, and contributions to renal disease progression in ADPKD remain unknown. We hypothesized that intrarenal MV rarefaction is present early on and is preceded by vascular transcriptional and metabolic changes. Pkd1RC/RC and wild type (WT) mice (n = 16 each) were studied at 1, 6, and 12 mo. Total kidney volume (TKV) was measured in vivo (MRI), whereas renal MV architecture [three-dimensional (3-D) micro-computed tomography, 3-D micro-CT], capillary density, perivascular fibrosis, and histomorphometric parameters were assessed ex vivo. In randomly selected Pkd1RC/RC and WT kidneys (n = 5, each/time point), mRNA-sequencing was performed to identify differentially expressed vasculature-related genes (differentially expressed genes, DEGs). Next, in young humans with ADPKD and matched controls (n = 10 each), plasma cellular energy metabolites were determined (LC-MS/MS), validated in an extended cohort (n = 32 and n = 16, respectively), and correlated with markers of disease severity and progression. Gene-metabolite interaction networks were generated to integrate DEGs in Pkd1RC/RC at 1 mo with metabolites dysregulated in individuals with ADPKD, which were further quantified in WT and Pkd1RC/RC kidneys. Renal MV density was preserved at 1 mo but progressively decreased at 6 and 12 mo, associated with capillary loss and perivascular fibrosis. A total of 110, 48, and 201 DEGs were identified at 1, 6, and 12 mo, respectively. Plasma gamma-aminobutyric acid (GABA), homocysteine (Hcy), and asymmetric dimethyl arginine (ADMA) levels were higher in humans with ADPKD vs. controls, interacted with DEGs implicated in inflammatory and innate immune response and Hcy metabolism, and correlated with TKV and renal blood flow. Our data demonstrate that intrarenal MV abnormalities present early in ADPKD and are preceded by vascular transcriptional and metabolic changes. The renal microcirculation may constitute an important therapeutic target in ADPKD, and its underlying biomarkers may serve to monitor its progression.NEW & NOTEWORTHY We provide the first longitudinal and most comprehensive analysis of the intrarenal microvasculature in a slowly progressive model of autosomal dominant polycystic kidney disease (ADPKD) and integrate the findings with studies in a young cohort of individuals with ADPKD. We identified vasculature-related pathways that could be targeted for therapeutic interventions and contribute promising, noninvasive biomarkers in patients with ADPKD. Alterations of the intrarenal microcirculation may affect drug delivery; a better understanding of its longitudinal changes may aid in treatment management.

Autosomal dominant polycystic kidney disease (ADPKD) is a heterogeneous inherited disease characterized by renal and extrarenal manifestations with progressive fluid-filled cyst development leading to end-stage renal disease. The rate of disease progression in ADPKD exhibits high inter- and intrafamilial variability suggesting involvement of modifier genes and/or environmental factors. Renal hypouricemia (RHUC) is an inherited disorder characterized by impaired tubular uric acid transport with severe complications, such as acute kidney injury and chronic kidney disease (CKD). However, the two disorders have distinct and well-delineated genetic, biochemical, and clinical findings. Only a few cases of coexistence of ADPKD and RHUC (type 1) in a single individual have been reported. We report a family with two members: an ADPKD 24-year-old female which presented bilateral renal cysts in utero and hypouricemia since age 5, and her mother with isolated hypouricemia. Next-generation sequencing identified two mutations in two genes PKD1 and SLC2A9 in this patient and one isolated SLC2A9 mutation in her mother, showing RHUC type 2, associated to CKD. The coexistence of these two disorders provides evidence of SLC2A9 variant could act as a modifier change, with synergistic actions, that could promote cystogenesis and rapid ADPKD progression. This is the first case of coexistence of PKD1 and SLC2A9 mutations treated with tolvaptan.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is caused by mutation of PKD1 or PKD2, which encode polycystin 1 and 2, respectively. The polycystins localize to primary cilia and the functional loss of the polycystin complex leads to the formation and progressive growth of fluid-filled cysts in the kidney. The pathogenesis of ADPKD is complex and molecular mechanisms connecting ciliary dysfunction to renal cystogenesis are unclear. Primary cilia mediate Hedgehog signaling, which modulates cell proliferation and differentiation in a tissue-dependent manner. Previously, we showed that Hedgehog signaling was increased in cystic kidneys of several PKD mouse models and that Hedgehog inhibition prevented cyst formation in embryonic PKD mouse kidneys treated with cAMP. Here, we show that in human ADPKD tissue, Hedgehog target and activator, Glioma 1, was elevated and localized to cyst-lining epithelial cells and to interstitial cells, suggesting increased autocrine and paracrine Hedgehog signaling in ADPKD, respectively. Further, Hedgehog inhibitors reduced basal and cAMP-induced proliferation of ADPKD cells and cyst formation in vitro. These data suggest that Hedgehog signaling is increased in human ADPKD and that suppression of Hedgehog signaling can counter cellular processes that promote cyst growth in vitro.

Background/Aims: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disorder with mutations in PKD1 or PKD2. This study aimed to identify novel PKD1 and PKD2 mutations in Chinese patients with ADPKD. Methods: Mutational analyses of both PKD genes were performed in 120 Chinese families with inherited ADPKD using long-range PCR and targeted next-generation sequencing approaches. Sanger sequencing was performed to check the positive mutations, while multiplex ligation-dependent probe amplification was adopted to examine those without mutations for the presence of large deletions. Results: A total of 93 mutations in PKD1 and PKD2 were identified in 98 Chinese families with ADPKD inheritance and the detection rate was 81.7% (98/120). The mutation rates of PKD1 and PKD2 were 91.4% (85/93) and 8.6% (85/93), respectively. Among the 93 mutations, 59.1% (55/93) were reported for the first time. A total of 65 mutations (26 nonsense, 33 frameshift, 2 large deletion, and 4 typical splicing mutations) were identified as definite pathogenic mutations. The remaining 28 mutations (21 missense, 3 in-frame deletion, and 4 atypical splicing mutations) were determined as probable pathogenic mutations. In addition, 9 de novo mutations were found by pedigree analysis. Correlation analysis between genotype and phenotype revealed that patients with PKD1 mutations or truncating mutations exhibited the most severe clinical outcome. Conclusion: The newly identified sites for known mutations will facilitate the early diagnosis and prediction of prognosis in patients with ADPKD, and provide fundamental genetic information for clinical intervention to prevent the inheritance of this disease in affected families.

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in the PKD1 and PKD2 genes, and often progresses to kidney failure. ADPKD progression is not uniform among patients, suggesting that factors secondary to the PKD1/2 gene mutation could regulate the rate of disease progression. Here we tested the effect of circadian clock disruption on ADPKD progression. Circadian rhythms are regulated by cell-autonomous circadian clocks composed of clock proteins. BMAL1 is a core constituent of the circadian clock. To disrupt the circadian clock, we deleted Bmal1 gene in the renal collecting ducts of the Pkd1RC/RC (RC/RC) mouse model of ADPKD (RC/RC;Bmal1f/f;Pkhd1cre, called DKO mice), and in Pkd1 knockout mouse inner medullary collecting duct cells (Pkd1Bmal1KO mIMCD3 cells). Only male mice were used. Human nephrectomy ADPKD kidneys showed altered clock gene expression when compared to normal control human kidneys. When compared to RC/RC kidneys, DKO kidneys showed significantly altered clock gene expression, increased cyst growth, cell proliferation, apoptosis and fibrosis. DKO kidneys also showed increased lipogenesis and cholesterol synthesis-related gene expression, and increased tissue triglyceride levels compared to RC/RC kidneys. Similarly, in vitro, Pkd1Bmal1KO cells showed altered clock genes, increased lipogenesis and cholesterol synthesis-related genes, and reduced fatty-acid oxidation-related gene expression compared to Pkd1KO cells. The Pkd1Bmal1KO cells showed increased cell proliferation compared to Pkd1KO cells, which was rescued by pharmacological inhibition of lipogenesis. Renal collecting duct specific Bmal1 gene deletion disrupted the circadian clock and triggered accelerated ADPKD progression by altering lipid metabolism-related gene expression.

INTRODUCTION: Autosomal dominant polycystic kidney disease (ADPKD) is caused by a mutation in PKD1 or PKD2; it occurs in approximately 1 in 1000 live births. The current literature shows a significant correlation between ADPKD and intracranial aneurysm formation. METHODS: This was a retrospective study that utilized the TriNetX Analytics network. Only patients &gt;18 were included in the analysis. Using ICD-10 codes, two groups of patients were created: patients with autosomal dominant polycystic kidney disease (ADPKD) and intracranial aneurysms and patients without ADPKD and with intracranial aneurysms (control). Odds ratios with 95% confidence intervals were calculated. The prevalence and rupture rate at 1 year, 5 years, and 10 years were determined. RESULTS: There were 26,614 patients with a diagnosis of ADPKD and 92,995,720 patients without ADPKD. The prevalence of an intracranial aneurysm in the ADPKD group versus the control is 7.39% and 0.25%, respectively. The odds ratio of aneurysm rupture in the ADPKD group versus the control at one year, five years, and ten years is 0.398 (0.324, 0.487), 0.477 (0.398, 0.57), and 0.49 (0.411, 0.584), respectively. CONCLUSIONS: ADPKD patients have a significantly higher prevalence of intracranial aneurysms than patients in the general population. However, we have determined that the aneurysm rupture at 1 year, 5 years, and 10 years is significantly lower in patients with ADPKD and intracranial aneurysms than in patients in the general population with intracranial aneurysms. This has implications for the screening and management of intracranial aneurysms in patients with ADPKD.

Background and Aims Thyroid hormone (TH) signaling plays a crucial role in the regulation of the cell differentiation state, cell cycle and metabolism in various organs. Low TH levels are observed in most patients with chronic kidney disease, and correlate with cell de-differentiation and reactivation of the cell cycle. Despite this knowledge, possible alterations of TH signaling in Autosomal Dominant Polycystic Kidney Disease (ADPKD) and the capacity of TH to modulate anti-cystogenic and renoprotective pathways have not yet been studied. In this study we aimed to (i) investigate the role of TH signaling in the pathogenesis of ADPKD in patients and experimental models, and (ii) assess whether the pharmacological modulation of this pathway with TH (T3, T4) and TH analogs could arrest or reverse ADPKD progression. Method Ninety patients with a diagnosis of ADPKD based on renal ultrasonography findings or genetic testing were included in the study and divided into five subgroups of chronic kidney disease stages, according to the KDIGO classification. Serum TH was measured using ELISA and chemiluminescent immunoassays. The correlation between TH levels and renal function parameter (eGFR) in these patients was assessed using linear regression. 3D polycystic tubules were engineered from patient-derived cells as previously described (Benedetti et al. 2016). For the in vivo experiments, PCK rats—an animal model of ADPKD—were treated with T4 (10 μg/kg) or vehicle by gavage from 4 to 11 weeks of age. Age-matched SD rats were followed for the same length of time and used as controls. Results The analysis of patients’ data showed a strong linear correlation between the levels of FT3 and eGFR, and corresponding inverse correlation between rT3 (the inactivated form of T3) and eGFR. Treating patients-derived tubules with THs strongly inhibited cyst formation and growth. Interestingly, the results were validated in engineered polycystic tubules from three ADPKD patients with different mutations (missense, splice-site and stop-gain) in the PKD1 gene, further confirming that T4 plays an essential role in the cystogenesis and, presumably, progression of the disease in humans. Treating PCK rats—an animal model of ADPKD—with T4 resulted in a significant increase in T4 serum levels and a simultaneous reduction in the size of the macrocystic area compared to vehicle-treated PCK rats. Most importantly, T4 serum levels positively correlated with a reduction in both the size of the macrocystic area and loss of protein into the urine, indicating that TH signaling plays a role in the growth of cysts, and that exogenous T4 can slow down cystogenesis and improve renal function. Interestingly, our mechanistic studies revealed that T4 exerts its anti-cystogenic effects, at least partially, by binding to the membrane receptor αvβ3 and activating the MAPK cascade. Conclusion These results suggest that TH signaling plays a role in the progression of ADPKD and timely administration of T4, ideally at a relatively early stage of the disease, could delay progression or even reverse key clinical features of ADPKD.

BACKGROUND AND AIMS The risk of urinary tract stone formation in patients with autosomal dominant polycystic kidney disease (ADPKD) is 20%, twice as high as in the normal population. The most important reason for this increased tendency to stone disease is thought to be anatomic changes in the kidney. To investigate metabolic factors that predispose to urinary system stone formation in individuals with ADPKD. METHOD A total of 180 volunteers who applied to our outpatient clinic between December 2019 and May 2021 were included in the study. Four groups were formed: patients with ADPKD and urinary system stones (ADPKD + STONE) (n = 42), patients with ADPKD but no stones (ADPKD + STONE FREE) (n = 43), stone patients without ADPKD (STONE) (n = 47) and healthy controls (HEALTHY) (n = 48) groups. Spot urine pH, 24-h urine volume, calcium, uric acid, oxalate, citrate, sodium and magnesium parameters were measured. STONE group data were obtained retrospectively. Along with these parameters, serum electrolyte, parathormone (PTH), ferritin, albumin, creatinine, urea and uric acid values were also compared. A P value of &amp;lt;.05 was considered significant for statistical analysis. RESULTS There was no statistically significant difference between the four groups in terms of age and gender (P &amp;gt; .05). The citrate value in 24-h urine was significantly lower in the ADPKD + STONE and ADPKD + STONE-FREE groups than the STONE and HEALTHY groups (P &amp;lt; .05). The citrate value in the 24-h urine was significantly lower in the STONE group than in the HEALTHY group (P &amp;lt; .05). The citrate value in 24-h urine did not differ significantly between the ADPKD + STONE and ADPKD + STONE FREE groups (P &amp;gt; .05). In the ADPKD + STONE and ADPKD + STONE-FREE groups, the 24-h urinary calcium value was significantly lower than the STONE and HEALTHY groups (P &amp;lt; .05). In the STONE group, the 24-h urinary calcium value was significantly higher than the HEALTHY group (P &amp;lt; .05). There was no significant difference in the 24-h urinary calcium value between the ADPKD + STONE and ADPKD + STONE FREE groups (P &amp;gt; .05). The uric acid level in 24-h urine was significantly lower in the ADPKD + STONE and ADPKD + STONE-FREE groups than in the HEALTHY group (P &amp;lt; .05). The uric acid value in the 24-h urine did not differ significantly between the ODPBH + STONE, ADPKD + STONE-FREE and STONE groups (P &amp;gt; .05). The uric acid value in 24-h urine did not differ significantly between the STONE and HEALTHY groups (P &amp;gt; .05). Oxalate, sodium and magnesium values in 24-h urine and 24-h urine volume did not differ significantly between the groups (P &amp;gt; .05). Urine pH value was significantly lower in the ADPKD + STONE, ADPKD + STONE-FREE and STONE groups than in the HEALTHY group (P &amp;lt; .05). The pH value did not differ significantly between ADPKD + STONE, ADPKD + STONE-FREE and STONE groups (P &amp;gt; .05). Serum PTH values were significantly higher in the ADPKD + STONE and ADPKD + STONE-FREE groups than in the HEALTHY group (P &amp;lt; .05). The PTH values did not differ significantly between the STONE and HEALTHY groups (P &amp;gt; .05). PTH values did not differ significantly between ODPBH + STONE, ADPKD + STONE-FREE and STONE groups (P &amp;gt; .05). There was no significant difference between the groups in terms of serum ferritin, sodium, potassium, calcium, phosphorus, magnesium and uric acid values (P &amp;gt; .05). CONCLUSION In our study, 24-h urine citrate level was found to be significantly lower in both ADPKD + STONE and ADPKD + STONE-FREE patients compared to the volunteers in the STONE and HEALTHY groups (P &amp;lt; .05). In conclusion, patients with ADPKD should also be evaluated for hypocitraturia in the outpatient clinic.