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Introduction: Autosomal recessive polycystic kidney disease (ARPKD) ranks among the most severe chronic kidney diseases (CKD). Its primary cause is variants in the Polycystic Kidney and Hepatic Disease 1 gene (PKHD1). The clinical spectrum of ARPKD varies widely, ranging from mild late‐onset symptoms to severe perinatal mortality. However, achieving an early genetic diagnosis in ARPKD patients before clinical symptoms appear proves challenging. Case Presentation: This case is a 4‐year‐old boy who experienced a convulsion characterized by a generalized tonic attack lasting approximately 3‐5 minutes and later sought treatment to our hospital. However, routine abdominal ultrasound examination accidentally detected that he had diffuse liver lesions, splenomegaly, and bilateral renal enlargement with renal pelvis dilation. Given the uncertainty regarding the underlying cause of the patient's structural abnormalities and convulsions, karyotyping, whole exome sequencing (WES), structural variant analysis (SV analysis) of whole genome sequencing (WGS) were recommended. The result of SV analysis revealed that he has an RBT impacting PKHD1 and the precise location of breakpoints was confirmed through Long‐Range Polymerase Chain Reaction (LR‐PCR). However, WES did not screen out pathogenic variants initially, the WES data was reviewed subsequently based on SV analysis results. Conclusion: We identified an infrequent variant combination, c.2507T>C (p.V836A) in PKHD1 and an RBT with broken PKHD1, which extends the genetic spectrum of ARPKD, and provide a basis for further genetic counselling to the family. [ABSTRACT FROM AUTHOR]

Background: Nephronophthisis (NPH) comprises a heterogeneous group of inherited renal ciliopathies clinically characterized by progressive kidney failure. So far, definite diagnosis is based on molecular testing only. Here, we studied the feasibility of NPHP1 and NPHP4 immunostaining of nasal epithelial cells to secure and accelerate the diagnosis of NPH. Methods: Samples of 86 individuals with genetically determined renal ciliopathies were analyzed for NPHP1 localization using immunofluorescence microscopy (IF). A sub-cohort of 35 individuals was also analyzed for NPHP4 localization. Western blotting was performed to confirm IF results. Results: NPHP1 and NPHP4 were both absent in all individuals with disease-causing NPHP1 variants including one with a homozygous missense variant (c.1027G > A; p.Gly343Arg) formerly classified as a "variant of unknown significance." In individuals with an NPHP4 genotype, we observed a complete absence of NPHP4 while NPHP1 was severely reduced. IF results were confirmed by immunoblotting. Variants in other genes related to renal ciliopathies did not show any impact on NPHP1/NPHP4 expression. Aberrant immunostaining in two genetically unsolved individuals gave rise for a further genetic workup resulting in a genetic diagnosis for both with disease-causing variants in NPHP1 and NPHP4, respectively. Conclusions: IF of patient-derived respiratory epithelial cells may help to secure and accelerate the diagnosis of nephronophthisis—both by verifying inconclusive genetic results and by stratifying genetic diagnostic approaches. Furthermore, we provide in vivo evidence for the interaction of NPHP1 and NPHP4 in a functional module. [ABSTRACT FROM AUTHOR]

Background: Autosomal recessive polycystic kidney disease (ARPKD) is a genetically inherited pediatric disorder. It is caused by a mutation in the PKHD1 gene located on chromosome 6. The predominant phenotype is characterized by early-onset bilateral enlarged kidneys, as well as fibrocystic changes in the kidney and liver. Fetuses or infants usually present with Potter syndrome, and they are more likely to develop severe renal insufficiency. Generally, patients die perinatally or in infancy. Liver involvement has been reported in adults with ARPKD who have survived the neonatal period and childhood. However, renal involvement is rarely expected in adulthood. The case is being presented for its clinical rarity, in addition to emphasize the critical role of NGS approaches in diagnosis. Case presentation: We hereby describe a 33-year-old female with adult-onset proteinuria and nephromegaly. She had a rare homozygous missense mutation of the PKHD1 gene with autosomal recessive inheritance. The proband has consanguineous heterozygote parents. The mutation was identified by whole-exome sequencing, and the results were confirmed by segregation analysis. Conclusion: Here, we reported a thorough literature review of late-onset autosomal recessive polycystic kidney disease. Furthermore, we explored the importance of genetic work-up in families with genetic disorders and consanguineous marriages, particularly in underdeveloped countries. [ABSTRACT FROM AUTHOR]

Background: Prenatal ultrasound findings of fetal bilateral echogenic kidneys accompanied by oligohydramnios can be highly stressful for both pregnant women and physicians. The diversity of underlying causes makes it challenging to confirm a prenatal diagnosis, predict postnatal outcomes, and counsel regarding recurrence risks in future pregnancies. Case Presentation: We report two cases of abnormal fetal echogenic kidneys with oligohydramnios detected in the early third trimester. Autosomal recessive polycystic kidney disease (ARPKD), a rare genetic syndrome, was initially suspected in both cases. However, postnatal diagnoses differed: the first case was confirmed as glomerulocystic kidney disease (GCKD) through renal pathology, while the second case was diagnosed as ARPKD with a compound heterozygous likely pathogenic PKHD1 mutation. Conclusion: Prenatal diagnosis of fetal echogenic kidneys with oligohydramnios should prioritize accurate diagnosis. Given the differences in the clinical spectrum, GCKD should be considered a differential diagnosis for this condition, particularly ARPKD. This study highlights the importance and benefits of molecular diagnosis and postnatal renal pathology for precise diagnosis and effective counseling. [ABSTRACT FROM AUTHOR]

Nagashima-type palmoplantar keratosis (NPPK) is a relatively common autosomal recessive dermatosis characterized by well-defined diffuse erythema and non-destructive hyperkeratosis on the palmoplantar areas, with swelling and whitening when exposed to water. The pathogenesis of NPPK can be attributable to altered structure and function of SERPINB7, environmental factors, barrier dysfunction and inflammatory response. There is no specific and standardized therapy for this disorder. Topical treatment is primary therapy although systemic drugs or surgery can be used for severe cases. Gentamicin, a targeted therapy for the disease, has shown some potential, but more clinical studies are still needed to verify its efficacy and safety. The aim of this review is to summarize the causative gene, pathogenesis and therapeutic strategies of NPPK. [ABSTRACT FROM AUTHOR]

Background: Autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD) are major genetic polycystic kidney diseases that can progress to end-stage kidney disease (ESKD). Longitudinal data on the clinical characteristics associated with clinical outcomes in polycystic kidney disease (PKD), including the development of ESKD and cardiovascular disease (CVD) are lacking in Japan. To address this unmet need the authors are establishing a novel, web-based, Nationwide Cohort Registry Study—the Japanese Registry of PKD (JRP). Methods: The JRP is a prospective cohort study for ADPKD (aim to recruit n = 1000 patients), and both a retrospective and prospective study for ARPKD (aim to recruit n = 100). In the prospective registry, patients will be followed-up for 10 years every 6 months and 12 months for patients with ADPKD and ARPKD, respectively. Data collection will be recorded on Research Electronic Data Capture (REDCap) starting on April 1, 2024, with recruitment ending on March 31, 2029. (jRCT 1030230618). Results: Data to be collected include: baseline data, demographics, diagnostic and genetic information, radiological and laboratory findings, and therapeutic interventions. During follow-up, clinical events such as development of ESKD, hospitalization, occurrence of extra kidney complications including CVD events, and death will be recorded, as well as patient-reported health-related quality of life for patients with ADPKD. Conclusions: The JRP is the first nationwide registry study for patients with ADPKD and ARPKD in Japan, providing researchers with opportunities to advance knowledge and treatments for ADPKD and ARPKD, and to inform disease management and future clinical practice. [ABSTRACT FROM AUTHOR]

Background/aim: Autosomal recessive polycystic kidney disease is an inherited kidney disease. This study aims to detect rare and common DNA variants of the PKHD1 gene using next-generation sequencing (NGS) and to classify them in terms of being pathogenic according to The American College of Medical Genetics and Genomics. Materials and methods: NGS analysis was performed on the DNA of 304 patients who were referred to Ege University Molecular Medicine Laboratory with suspected polycystic kidney disease. Results: As a result, a total of 82 different DNA variants, 16 of which were novel, were detected. The breakdown of the variants found is as follows: 73 (89.02%) were missense variants, six (7.32%) nonsense variants, two (2.44%) frameshift deletions, and one (1.22%) nonframeshift deletion. According to The American College of Medical Genetics and Genomics classification of these variants, 26 were benign (Class 5), two were likely benign (Class 4), 36 were of uncertain significance (Class 3), and nine were likely pathogenic (Class 2), nine of which are pathogenic variants (Class 1). Heterozygosity was found in 39 (63.9%) patients, homozygosity in six (9.8%) patients, compound heterozygosity in 12 (19.7%) patients, and complex genotype in four (6.6%) patients in which variants in Class 1, Class 2 and Class 3 were determined according to ACMG classification. When the exon distributions of the DNA variants detected in the PKHD1 gene were analyzed, the most common exons of the DNA variant are exon 32 (n = 9), exon 58 (n = 8), exon 67 (n = 6), exon 61 (n = 5), 30 exons (n = 4). Conclusion: This fast and economical molecular diagnostic approach will provide a reliable prenatal diagnostic option, enabling definitive disease diagnosis and the identification of carriers. [ABSTRACT FROM AUTHOR]

The incidence of rare diseases is expected to be comparatively higher in the Middle East and North Africa (MENA) region than in other parts of the world, attributed to the high prevalence of consanguinity. Most MENA countries share social and economic statuses, cultural relativism, religious beliefs, and healthcare policies. Polycystic kidney diseases (PKDs) are the most common genetic causes of kidney failure, accounting for nearly 8.0% of dialysis cases. The development of PKDs is linked to variants in several genes, including PKD1, PKD2, PKHD1, DZIP1L, and CYS1. Autosomal recessive PKD (ARPKD) is the less common yet aggressive form of PKD. ARPKD has an estimated incidence between 1:10,000 and 1:40,000. Most patients with ARPKD require kidney replacement therapy earlier than patients with autosomal dominant polycystic kidney disease (ADPKD), often in their early years of life. This review gathered data from published research studies and reviews of ARPKD, highlighting the epidemiology, phenotypic presentation, investigations, genetic analysis, outcomes, and management. Although limited data are available, the published literature suggests that the incidence of ARPKD may be higher in the MENA region due to consanguineous marriages. Patients with ARPKD from the MENA region usually present at a later disease stage and have a relatively short time to progress to kidney failure. Limited data are available regarding the management practice in the region, which warrants further investigations. [ABSTRACT FROM AUTHOR]

Cystic kidney diseases encompass a range of genetic disorders in which the primary cilia of the cells are affected and thereby cysts form as a result. There are an increasing range of cystic renal diseases recognized due to the advances in genomics. The most common genetic kidney condition is autosomal dominant polycystic kidney disease (ADPKD). ADPKD leads to renal failure in adulthood. In children, hypertension is common and if treated, may slow down renal decline. The most common cystic kidney disease causing renal failure in children is autosomal recessive polycystic kidney disease (ARPKD). ARPKD also affects the liver. These conditions often have extra-renal features which also need to be addressed. Until recently, treatments were mainly supportive but now it is possible to slow down development of cyst formation and renal decline in ADPKD. This raises hope for treatment for other cystic renal conditions as more genes are identified and underlying mechanisms defined. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Contemporary Pediatrics is the property of Xiangya Medical Periodical Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Renal ciliopathies are a group of genetic disorders that affect the function of the primary cilium in the kidney, as well as other organs. Since primary cilia are important for regulation of cell signaling pathways, ciliary dysfunction results in a range of clinical manifestations, including renal failure, cyst formation, and hypertension. We summarize the current understanding of the pathophysiological and pathological features of renal ciliopathies in childhood, including autosomal dominant and recessive polycystic kidney disease, nephronophthisis, and Bardet-Biedl syndrome, as well as skeletal dysplasia associated renal ciliopathies. The genetic basis of these disorders is now well-established in many cases, with mutations in a large number of cilia-related genes such as PKD1, PKD2, BBS, MKS, and NPHP being responsible for the majority of cases. Renal ciliopathies are broadly characterized by development of interstitial fibrosis and formation of multiple renal cysts which gradually enlarge and replace normal renal tissue, with each condition demonstrating subtle differences in the degree, location, and age-related development of cysts and fibrosis. Presentation varies from prenatal diagnosis of congenital multisystem syndromes to an asymptomatic childhood with development of complications in later adulthood and therefore clinicopathological correlation is important, including increasing use of targeted genetic testing or whole genome sequencing, allowing greater understanding of genetic pathophysiological mechanisms. [ABSTRACT FROM AUTHOR]

The article addresses the increasing recognition of genetic factors in chronic kidney disease (CKD) and the role of genetics in improving diagnosis and management. Topics include the growing importance of genetic testing for CKD, advancements in understanding the genetic basis of kidney diseases, and the evolving identification of genetic causes of CKD in both children and adults.

Objective: To explore the role of polycystic kidney and hepatic disease 1-like 1 (PKHD1L1) in lung adenocarcinoma (LUAD). Methods: Bioinformatics tools were utilized to examine the clinical profile of PKHD1L1 and chromobox protein homolog 7 (CBX7) in LUAD. The Cell Counting Kit-8, colony formation, terminal deoxynucleotidyl transferase dUTP nick end labeling, Transwell, and wound-healing assays were carried out to assess the proliferative, apoptotic, invasive, and migrative capacities of the cells. Furthermore, the interrelation between PKHD1L1 and CBX7 was validated using a co-immunoprecipitation assay. A LUAD mice model was constructed by subcutaneous injection of A549 cells. Finally, immunohistochemical staining was performed to evaluate CBX7 and Ki67 expression. Results: PKHD1L1 was downregulated in LUAD and predicted dismal outcomes in patients with LUAD. PKHD1L1 upregulation repressed the proliferative, invasive, and migrative capabilities of A549 cells and exacerbated the apoptotic rate. Additionally, PKHD1L1 may bind to CBX7 and positively modulate CBX7 expression. CBX7 deletion partly abrogated the effects of PKHD1L1 upregulation on the cellular biological activities in A549 cells. Furthermore, the PKHD1L1/CBX7 axis regulates the Hippo signaling pathway in A549 cells. PKHD1L1 restricted tumor growth in LUAD xenograft mice; this was partly abolished by CBX7 knockdown. Conclusion: PKHD1L1 can hinder LUAD progression by regulating CBX7-mediated Hippo signaling. [ABSTRACT FROM AUTHOR]

Background. Polycystic kidney disease is a cystic genetic disease. There are two forms: an autosomal dominant one, more common and typical of adults, and an autosomal recessive one, rarer and present in childhood. The autosomal dominant form is caused by genetic mutations of the PKD1 gene in 85% of cases and of PKD2 in 10-15% of cases. Case Report. We reported a case of 56-year-old woman with ADPKD, who had a kidney transplant and who was hospitalized for respiratory failure from Covid 19 disease. She was intubated, sedated and dialyzed, treated with antibiotics, immunosuppressants, diuretics and heparin. CT scan of the abdomen showed multiple cysts of various sizes in the liver and multiple cysts in the kidneys. The patient died after 20 days because she was unresponsive to therapy. The autopsy showed milky ascitic fluid in the abdomen, massive gastric haemorrhage, intestinal fungal plaques, hepatic and renal polycystosis. The kidneys measured a total of 27 cm with a total weight of about 9 kg. The liver parenchyma appeared cavernous with multiple cysts. The kidney cysts contained bloody liquid. Conclusions. The case demonstrates how important it is in these subjects to evaluate not only the kidneys but also the liver which could present polycystosis and cause liver failure, affecting the severity of the pathology and death. This data is important to emphasize in the clinical management of these patients a close monitoring of liver function also from a preventative perspective in life. [ABSTRACT FROM AUTHOR]

Background: To investigate whether the novel mutation of PKHD1 could cause polycystic kidney disease by affecting splicing with a recessive inheritance pattern. Methods: A nonconsanguineous Chinese couple with two recurrent pregnancies showed fetal enlarged echogenic polycystic kidney and oligoamnios were recruited. Pedigree WES, minigene splicing assay experiment and following bioinformatics analysis were performed to verify the effects, and inheritance pattern of diseasing-causing mutations. Results: WES revealed that both fetuses were identified as carrying the same novel mutation c.3592_3628 + 45del, p.? and c.11207 T>C, p.(Ile3736Thr) in the PKHD1 gene (NM_138694.4), which inherited from the father and mother respectively. Both bioinformatic method prediction and minigene splicing assay experience results supported the mutation c.3592_3628 + 45del, p.? affects the splicing of the PKHD1 transcript, resulting in exon 31 skipping. Another missense mutation c.11207 T>C, p.(Ile3736Thr) has a low frequency in populations and is predicted to be deleterious by bioinformatic methods. Conclusion: These findings provide a direct clinical and functional evidence that the truncating mutations of the PKHD1 gene could lead to more severe phenotypes, and cause ARPKD as a homozygous or compound heterozygous pattern. Our study broadens the variant spectrum of the PKHD1 gene and provides a basis for genetic counseling and diagnosis of ARPKD. [ABSTRACT FROM AUTHOR]

Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease and is one of the most frequent genetic causes for kidney failure (KF) in children and adolescents. Over 20 genes cause NPHP and over 90 genes contribute to renal ciliopathies often involving multiple organs. About 15–20% of NPHP patients have additional extrarenal symptoms affecting other organs than the kidneys. The involvement of additional organ systems in syndromic forms of NPHP is explained by shared expression of most NPHP gene products in centrosomes and primary cilia, a sensory organelle present in most mammalian cells. This finding resulted in the classification of NPHP as a ciliopathy. If extrarenal symptoms are present in addition to NPHP, these disorders are defined as NPHP-related ciliopathies (NPHP-RC) and can involve the retina (e.g., with Senior-Løken syndrome), CNS (central nervous system) (e.g., with Joubert syndrome), liver (e.g., Boichis and Arima syndromes), or bone (e.g., Mainzer-Saldino and Sensenbrenner syndromes). This review focuses on the pathological findings and the recent genetic advances in NPHP and NPHP-RC. Different mechanisms and signaling pathways are involved in NPHP ranging from planar cell polarity, sonic hedgehog signaling (Shh), DNA damage response pathway, Hippo, mTOR, and cAMP signaling. A number of therapeutic interventions appear to be promising, ranging from vasopressin receptor 2 antagonists such as tolvaptan, cyclin-dependent kinase inhibitors such as roscovitine, Hh agonists such as purmorphamine, and mTOR inhibitors such as rapamycin. [ABSTRACT FROM AUTHOR]

Cowden syndrome (CS) is a rare autosomal dominant genodermatosis caused by a heterozygous germline mutation in the PTEN gene, found in nearly 80% of cases. It is characterized by multiple benign hamartomas which manifest across various organs. This condition is further distinguished by its association with macrocephaly, facial trichilemmomas, acral keratoses, papillomatous papules, and a heightened susceptibility to certain malignant neoplasms, particularly affecting the thyroid, endometrium, and the breast (OMIM no. 58350). In this report, we detail the case of an Indian patient presenting with macrocephaly and multiple blackish pigmented areas on the face, alongside several small papules on the dorsum of the hands, and the presence of gastric and duodenal polyps, among other symptoms. Genetic analysis through Sanger sequencing of the PTEN gene revealed a heterozygous nonsense pathogenic variant (ENST00000371953.8: c.388C > T, p.Arg130Ter), thereby confirming a CS diagnosis. The report encompasses a comprehensive review of the existing literature, emphasizing the significance of genetic evaluation and discussing the intricacies of managing patients diagnosed with CS. [ABSTRACT FROM AUTHOR]

Serving as the cell's sensory antennae, primary cilia are linked to numerous human genetic diseases when they malfunction. DZIP1L, identified as one of the genetic causes of human autosomal recessive polycystic kidney disease (ARPKD), is an evolutionarily conserved ciliary basal body protein. Although it has been reported that DZIP1L is involved in the ciliary entry of PKD proteins, the underlying mechanism remains elusive. Here, an uncharacterized role of DZIP1L is reported in modulating the architecture and function of transition fibers (TFs), striking ciliary base structures essential for selective cilia gating. Using C. elegans as a model, C01G5.7 (hereafter termed DZIP‐1) is identified as the sole homolog of DZIP1L, which specifically localizes to TFs. While DZIP‐1 or ANKR‐26 (the ortholog of ANKRD26) deficiency shows subtle impact on TFs, co‐depletion of DZIP‐1 and ANKR‐26 disrupts TF assembly and cilia gating for soluble and membrane proteins, including the ortholog of ADPKD protein polycystin‐2. Notably, the synergistic role for DZIP1L and ANKRD26 in the formation and function of TFs is highly conserved in mammalian cilia. Hence, the findings illuminate an evolutionarily conserved role of DZIP1L in TFs architecture and function, highlighting TFs as a vital part of the ciliary gate implicated in ciliopathies ARPKD. [ABSTRACT FROM AUTHOR]

Background: Autosomal recessive polycystic kidney disease (ARPKD) is a rare inherited cystic disease characterized by bilateral renal cyst formation and congenital liver fibrosis. Cardiovascular disorders such as noncompaction of ventricular myocardium (NVM) have not been reported with ARPKD. Case presentation: A 5-month-old girl was examined after presenting with a fever and turbid urine for one day and was diagnosed as urinary tract infection. Urinary ultrasound showed multiple round, small cysts varying in size in both kidneys. Genetic testing revealed two heterozygous mutations and one exon deletion in the polycystic kidney and hepatic disease 1 gene, indicating a diagnosis of ARPKD. During hospitalization, she was found to have chronic heart failure after respiratory tract infection, with an ejection fraction of 29% and fraction shortening of 13%. When the patient was 15 months old, it was found that she had prominent trabeculations and deep intertrabecular recesses with the appearance of blood flow from the ventricular cavity into the intertrabecular recesses by echocardiography. The noncompaction myocardium was 0.716 cm and compaction myocardium was 0.221 cm (N/C = 3.27), indicating a diagnosis of NVM. Liver and kidney function remained normal during four-year follow-up. Conclusions: This is the first report of NVM in a patient with ARPKD. It is unsure if the coexistence of NVM and ARPKD is a coincidence or they are different manifestations of ciliary dysfunction in the heart and kidneys. [ABSTRACT FROM AUTHOR]

Humans are predisposed to gout because they lack uricase that converts uric acid to allantoin. Rodents have uricase, resulting in low basal serum uric acid. A uricase inhibitor raises serum uric acid in rodents. There were two aims of the study in polycystic kidney disease (PKD): 1) to determine whether increasing serum uric acid with the uricase inhibitor, oxonic acid, resulted in faster cyst growth and 2) to determine whether treatment with the xanthine oxidase inhibitor, oxypurinol, reduced the cyst growth caused by oxonic acid. Orthologous models of human PKD were used: PCK rats, a polycystic kidney and hepatic disease 1 (Pkhd1) gene model of autosomal recessive PKD (ARPKD) and Pkd1RC/RC mice, a hypomorphic Pkd1 gene model. In PCK rats and Pkd1RC/RC mice, oxonic acid resulted in a significant increase in serum uric acid, kidney weight, and cyst index. Mechanisms of increased cyst growth that were investigated were proinflammatory cytokines, the inflammasome, and crystal deposition in the kidney. Oxonic acid resulted in an increase in proinflammatory cytokines in the serum and kidney in Pkd1RC/RC mice. Oxonic acid did not cause activation of the inflammasome or uric acid crystal deposition in the kidney. In Pkd1RC/RC male and female mice analyzed together, oxypurinol decreased the oxonic acid-induced increase in cyst index. In summary, increasing serum uric acid by inhibiting uricase with oxonic acid results in an increase in kidney weight and cyst index in PCK rats and Pkd1RC/RC mice. The effect is independent of inflammasome activation or crystal deposition in the kidney. NEW & NOTEWORTHY: This is the first reported study of uric acid measurements and xanthine oxidase inhibition in polycystic kidney disease (PKD) rodents. Raising serum uric acid with a uricase inhibitor resulted in increased kidney weight and cyst index in Pkd1RC/RC mice and PCK rats, elevated levels of proinflammatory cytokines in the serum and kidney in Pkd1RC/RC mice, and no uric acid crystal deposition or activation of the caspase-1 inflammasome in the kidney. [ABSTRACT FROM AUTHOR]

Renal cell carcinoma (RCC) is the most common solid lesion within the kidney and accounts for most kidney malignancies. The primary tumor size primarily determines the risk of metastasis in RCC. Literature rarely describes metastasis in tumors less than 2 cm; in fact, around 1/3 of RCC reported cases had metastatic disease at the time of diagnosis. RCC tends to metastasize to the lung in half of the patients, to the bones or the liver in 1/3 of patients, and the brain in 5% of all cases. RCC can metastasize to almost every organ in the human body. However, their metastases to the ovaries are incredibly uncommon. In this report, we describe a female presented with the smallest RCC (1cm) that metastasized to the ovary in a patient with previously undiagnosed autosomal dominant polycystic kidney disease (ADPKD). This case report aimed to raise physicians’ awareness of the possibility of metastasis in RCC regardless of tumor size and that metastatic RCC could be the first presentation of patients with ADPKD. [ABSTRACT FROM AUTHOR]

The article presents diagnostic cases from July to December 2023. Topics include the identification and characteristics of mediastinal lymphoma in an 8-year-old Cambridge mare, the diagnosis and surgical treatment of osteomyelitis in an 11-year-old Gypsy Cob stallion, and the confirmation of Rhodococcus equi infection in a 6-week-old filly from Waikato.

Polycystic liver disease (PLD) is a rare condition observed in three genetic diseases, including autosomal dominant polycystic liver disease (ADPLD), autosomal dominant polycystic kidney disease (ADPKD), and autosomal recessive polycystic kidney disease (ARPKD). PLD usually does not impair liver function, and advanced PLD becomes symptomatic when the enlarged liver compresses adjacent organs or increases intra-abdominal pressure. Currently, the diagnosis of PLD is mainly based on imaging, and genetic testing is not required except for complex cases. Besides, genetic testing may help predict patients' prognosis, classify patients for genetic intervention, and conduct early treatment. Although the underlying genetic causes and mechanisms are not fully understood, previous studies refer to primary ciliopathy or impaired ciliogenesis as the main culprit. Primarily, PLD occurs due to defective ciliogenesis and ineffective endoplasmic reticulum quality control. Specifically, loss of function mutations of genes that are directly involved in ciliogenesis, such as Pkd1, Pkd2, Pkhd1, and Dzip1l, can lead to both hepatic and renal cystogenesis in ADPKD and ARPKD. In addition, loss of function mutations of genes that are involved in endoplasmic reticulum quality control and protein folding, trafficking, and maturation, such as PRKCSH, Sec63, ALG8, ALG9, GANAB, and SEC61B, can impair the production and function of polycystin1 (PC1) and polycystin 2 (PC2) or facilitate their degradation and indirectly promote isolated hepatic cystogenesis or concurrent hepatic and renal cystogenesis. Recently, it was shown that mutations of LRP5, which impairs canonical Wnt signaling, can lead to hepatic cystogenesis. PLD is currently treated by somatostatin analogs, percutaneous intervention, surgical fenestration, resection, and liver transplantation. In addition, based on the underlying molecular mechanisms and signaling pathways, several investigational treatments have been used in preclinical studies, some of which have shown promising results. This review discusses the clinical manifestation, complications, prevalence, genetic basis, and treatment of PLD and explains the investigational methods of treatment and future research direction, which can be beneficial for researchers and clinicians interested in PLD. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease is a renal development anomaly characterized by cystic transformation in renal parenchyma. ARPKD is more common in children. We present the case of a premature newborn, female, 36-37 weeks gestation, small for gestational age (SGA) originating from a completely unmonitored pregnancy, diagnosed upon admission to the clinic with unilateral multicystic dysplastic kidney. The condition complicated by a urinary tract infection with E. coli. This newborn displayed no clinical symptoms, was carefully monitored during hospitalization, and received antibiotic treatment. Antenatal ultrasound screening can aid in the early diagnosis of congenital anomalies and determining the appropriate course of action. [ABSTRACT FROM AUTHOR]

Copyright of Pamukkale Medical Journal is the property of Pamukkale Journal of Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This document is a set of posttest questions from the journal FP Essentials. The questions cover various topics related to renal and urinary conditions, such as glomerulonephritis, nephrotic syndrome, renal cell carcinoma, and urinary tract infections. The questions provide multiple-choice options and aim to test the reader's knowledge on these topics. The document does not provide any additional information or explanations beyond the questions themselves. [Extracted from the article]

Tay-Sachs disease (TSD) and its severe form Sandhoff disease (SD) are autosomal recessive lysosomal storage metabolic disorders, which often result into excessive GM2 ganglioside accumulation predominantly in lysosomes of nerve cells. Although patients with these diseases appear normal at birth, the progressive accumulation of undegraded GM2 gangliosides in neurons leads to early death accompanied by manifestation of motor difficulties and gradual loss of behavioral skills. Unfortunately, there is still no effective treatment available for TSD/SD. The present study highlights the importance of cinnamic acid (CA), a naturally occurring aromatic fatty acid present in a number of plants, in inhibiting the disease process in a transgenic mouse model of SD. Oral administration of CA significantly attenuated glial activation and inflammation and reduced the accumulation of GM2 gangliosides/glycoconjugates in the cerebral cortex of Sandhoff mice. Besides, oral CA also improved behavioral performance and increased the survival of Sandhoff mice. While assessing the mechanism, we found that oral administration of CA increased the level of peroxisome proliferator-activated receptor α (PPARα) in the brain of Sandhoff mice and that oral CA remained unable to reduce glycoconjugates, improve behavior and increase survival in Sandhoff mice lacking PPARα. Our results indicate a beneficial function of CA that utilizes a PPARα-dependent mechanism to halt the progression of SD and thereby increase the longevity of Sandhoff mice. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease (ARPKD) is often associated with hepatobiliary disease in the form of hepatic fibrosis and/or Caroli disease. Combined liver–kidney transplantation (CLKT) is a transplant modality of choice in children with both end-stage renal disease (ESRD) and severe hepatic disease. However, there is no consensus on whether children with ARPKD-associated ESRD without severe hepatic disease can be treated with isolated kidney transplantation (KT) without the need for CLKT. We retrospectively studied the efficacy of isolated KT in children with ARPKD without severe hepatic disease, and followed the course of hepatic disease post KT. This is a single-center study of three children with ARPKD and ESRD who underwent isolated KT. None of them had severe hepatic disease at the time of KT. All children were clinically diagnosed with ARPKD in the immediate postnatal period. All had hepatic fibrosis of varying degrees and two had intrahepatic biliary duct (IHBD) dilatation. None had gastrointestinal (GI) bleed, portal hypertension or cholangitis. Two children had preemptive KT. Pre-transplant unilateral or bilateral native nephrectomy were performed for two children, and one underwent unilateral native nephrectomy at the time of KT. The median creatinine clearance at a median post-KT follow-up of 24 months was 60.3 mL/min/1.73 m2. The two-year graft and patient survival were both 100%. Post KT, all three patients continued to demonstrate evidence of hepatic fibrosis and IHBD on sonogram; however, none of them were either evaluated for or required liver transplantation given normal synthetic liver function and absence of portal hypertension or other severe hepatobiliary disease. There were no adverse events observed such as cholangitis, GI bleed, or multiorgan failure. Hence, an excellent short-term graft and patient survival was demonstrated in this study of children with ARPKD and mild to moderate hepatic disease who received isolated KT. Long-term follow-up and larger studies are important to assess the efficacy of isolated KT in this subset of children with ARPKD. [ABSTRACT FROM AUTHOR]

Combined liver‐kidney transplantation (CLKT) is a surgical procedure that involves transplanting both liver and kidney organs. There are two types of CLKT: simultaneous liver‐kidney transplantation (smLKT) and sequential LKT (sqLKT). CLKT accounts for a small percentage of liver transplantations (LTs), particularly in pediatric cases. Nevertheless, the procedure has demonstrated excellent outcomes, with high survival rates and lower rejection rates. The main indications for CLKT in pediatric patients differ somewhat from that in adults, in which end‐stage kidney disease after LT is the major indication. In children, congenital diseases are common reason for performing CLKT; the examples of such diseases include autosomal recessive polycystic kidney disease with congenital hepatic fibrosis which equally affects both organs, and primary hyperoxaluria type 1, a primary liver disease leading kidney failure. The decision between smLKT or sqLKT depends on the dominant organ failure, the specific pathophysiology, and available organ sources. However, there remain significant surgical and societal challenges surrounding CLKT. Innovations in pharmacology and genetic engineering have decreased the necessity for CLKT in early‐diagnosed cases without portal hypertension or kidney replacement therapy. Nonetheless, these advancements are not universally accessible. Therefore, decision‐making algorithms should be crafted, considering region‐specific organ allocation systems and prevailing medical environments. [ABSTRACT FROM AUTHOR]

Background/Aims: The PCK rat model of polycystic kidney disease is characterized by the progressive development of renal medullary cysts. Here, we evaluated the suitability of high resolution ultrasonography (HRU) to assess the kidney and cyst volume in PCK rats, testing three different ultrasound image analysis methods, and correlating them with kidneys weights and histological examinations. Methods: After inducing anesthesia, PCK rats (n=18) were subjected to HRU to visualize the kidneys, to perform numeric and volumetric measurements of the kidney and any cysts observed, and to generate 3-dimensional images of the cysts within the kidney parenchyma. Results: HRU provided superior information in comparison to microscopic analysis of stained kidney sections. HRU-based kidney volumes correlated strongly with kidney weights (R2=0.809; P<0.0001). Conclusion: HRU represents a useful diagnostic tool for kidney and cyst volume measurements in PCK rats. Sequential HRU examinations may be useful to study the effect of drugs on cyst growth without the need to euthanize experimental animals. [ABSTRACT FROM AUTHOR]

Renal cystic diseases (RCDs) can arise from utero to early adulthood and present with a variety of symptoms including renal, hepatic, and cardiovascular manifestations. It is well known that common RCDs such as autosomal polycystic kidney disease and autosomal recessive kidney disease are linked to genes such as PKD1 and PKHD1, respectively. However, it is important to investigate the genetic pathophysiology of how these gene mutations lead to clinical symptoms and include some of the less-studied RCDs, such as autosomal dominant tubulointerstitial kidney disease, multicystic dysplastic kidney, Zellweger syndrome, calyceal diverticula, and more. We plan to take a thorough look into the genetic involvement and clinical sequalae of a number of RCDs with the goal of helping to guide diagnosis, counseling, and treatment. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease is an early onset inherited hepatorenal disorder affecting around 1 in 20,000 births with no approved specific therapies. The disease is almost always caused by variations in the polycystic kidney and hepatic disease 1 gene, which encodes fibrocystin (FC), a very large, single‐pass transmembrane glycoprotein found in primary cilia, urine and urinary exosomes. By comparison to proteins involved in autosomal dominant PKD, our structural and molecular understanding of FC has lagged far behind such that there are no published experimentally determined structures of any part of the protein. Bioinformatics analyses predict that the ectodomain contains a long chain of immunoglobulin‐like plexin‐transcription factor domains, a protective antigen 14 domain, a tandem G8‐TMEM2 homology region and a sperm protein, enterokinase and agrin domain. Here we review current knowledge on the molecular function of the protein from a structural perspective. [ABSTRACT FROM AUTHOR]

Introduction: The PKHD1 (Polycystic Kidney and Hepatic Disease 1) gene is essential for producing fibrocystin or polyductin, which is crucial in various cellular functions. Mutations in PKHD1 have been found to be involved in the development and progression of colorectal cancer (CRC). Along with APC, TP53, and KRAS, PKHD1 is one of the most frequently mutated genes in CRC. PKHD1 expression is governed by the Wnt/PCP pathway, often dysregulated in CRC. Targeting this pathway, crucial for CRC progression, could unveil potential therapeutic strategies for colon cancer treatment. Methods: This study examined an in-house dataset of 3702 colon cancer samples, analyzing mutation landscapes, clinical features, tumor mutational burden (TMB), microsatellite instability (MSI), and chromosomal instability (CIN) score. For the survival analysis of PKHD1 patients, survival data of 436 colon adenocarcinoma samples were obtained from TCGA dataset. Additionally, 433 samples from TCGA with RNA-seq data were used for the assessment of immune cell infiltration and gene set enrichment analysis. Results: Polycystic Kidney and Hepatic Disease 1 mutation was detected in 424 colon cancer patients from our in-house cohort and was associated with increased TMB, higher MSI, and lower CIN score. Importantly, within the TCGA dataset, PKHD1 mutations were identified as an independent prognostic factor, not merely correlated with established prognostic biomarkers, and were associated with poorer overall survival outcomes. In terms of immune response, these mutations correlated with increased enrichment scores for 12 immune cell types, including B cell plasma, macrophages, and naive CD4+ T cells. Additionally, interferon alpha and interferon-gamma gene sets were significantly down-regulated in patients with PKHD1 mutations (FDA q-value<0.1). Conclusions: Overall, these findings suggest that PKHD1 may be a potential biomarker for the prognosis of colon cancer and provide some insight for personalized immunotherapy. [ABSTRACT FROM AUTHOR]

Thurston syndrome ( oral ‑ facial ‑ digital syndromes [OFDS] Type V) is characterized by median cleft lip, postaxial polydactyly of hands and feet, and other oral manifestations. It is one of the OFDS described earlier in the literature. It is commonly seen in individuals of Indian origin and has autosomal recessive inheritance. This article presents two Indian female siblings with median upper lip cleft associated with postaxial hexadactyly of both hands. Rarely have such cases been reported by any author. Majority of the previously reported cases are males. This is the first case report of female siblings with Thurston syndrome. [ABSTRACT FROM AUTHOR]

Autosomal recessive polycystic kidney disease (ARPKD; MIM#263200) is a severe, hereditary, hepato-renal fibrocystic disorder that leads to early childhood morbidity and mortality. Typical forms of ARPKD are caused by pathogenic variants in the PKHD1 gene, which encodes the fibrocystin/polyductin (FPC) protein. MYC overexpression has been proposed as a driver of renal cystogenesis, but little is known about MYC expression in recessive PKD. In the current study, we provide the first evidence that MYC is overexpressed in kidneys from ARPKD patients and confirm that MYC is upregulated in cystic kidneys from cpk mutant mice. In contrast, renal MYC expression levels were not altered in several Pkhd1 mutant mice that lack a significant cystic kidney phenotype. We leveraged previous observations that the carboxy-terminus of mouse FPC (FPCCTD) is proteolytically cleaved through Notch-like processing, translocates to the nucleus, and binds to double stranded DNA, to examine whether the FPC-CTD plays a role in regulating MYC/Myc transcription. Using immunofluorescence, reporter gene assays, and ChIP, we demonstrate that both human and mouse FPC-CTD can localize to the nucleus, bind to the MYC/Myc P1 promoter, and activate MYC/Myc expression. Interestingly, we observed species-specific differences in FPC-CTD intracellular trafficking. Furthermore, our informatic analyses revealed limited sequence identity of FPC-CTD across vertebrate phyla and database queries identified temporal differences in PKHD1/Pkhd1 and CYS1/Cys1 expression patterns in mouse and human kidneys. Given that cystin, the Cys1 gene product, is a negative regulator of Myc transcription, these temporal differences in gene expression could contribute to the relative renoprotection from cystogenesis in Pkhd1-deficient mice. Taken together, our findings provide new mechanistic insights into differential mFPC-CTD and hFPCCTD regulation of MYC expression in renal epithelial cells, which may illuminate the basis for the phenotypic disparities between human patients with PKHD1 pathogenic variants and Pkhd1-mutant mice. [ABSTRACT FROM AUTHOR]

Homozygous deletion of NPHP1 can lead to isolated nephronophthisis (NPHP) and syndromic disorders. However, the phenotype of scalp tumor and hydroureteronephrosis in NPHP patients with homozygous deletion of NPHP1 has not been reported. Clinical data, laboratory results, and genetic testing of 4 NPHP patients were collected. Examination of their eyes, heart, and urinary tract and of their hepatobiliary, skeletal, and central nervous systems was evaluated. Isolated NPHP was observed in 1 case, and syndromic disorders were observed in the other 3 patients. Their syndromic disorders showed NPHP combined with central nervous system defects, eye involvement, scalp tumor, arachnoid cyst, or hydroureteronephrosis. Large homozygous deletions covering the whole NPHP1 gene locus were identified in all 4 patients. We report a novel phenotype of scalp tumor and hydroureteronephrosis in NPHP patients with homozygous deletion of NPHP1, paving an avenue for further research on NPHP1 -associated deformity in the skin and the urinary system. [ABSTRACT FROM AUTHOR]

Objective: Chromosomal microarray (CMA) is primarily used for the diagnosis of chromosomal deletions and duplications that have a direct phenotype based solely on that copy number variation (CNV) without other genetic changes. However, CNVs that contain a gene associated with a recessive disorder confer risk for that disorder should a second pathogenic variant be present in the other copy of the gene. The study aimed to propose a protocol to be considered for follow up testing after the detection of CNV containing an autosomal recessive gene on prenatal sample via chromosomal microarray. Methods: We present 5 cases involving prenatal diagnosis where CMA identified changes in an autosomal recessive gene conferring carrier status and discuss management of this finding. Results: Algorithm of selecting different diagnostic genetic testing after the detection of CNV containing an autosomal recessive gene on prenatal sample via chromosomal microarray has been created to help practitioners involved in this process. Conclusion: We recommend that CNV’s involving autosomal recessive genes identified by CMA be treated as any other carrier status. The parents should be encouraged to pursue genetic testing to determine their carrier status of the autosomal recessive conditions and/or additional prenatal diagnostic test on the fetus. [ABSTRACT FROM AUTHOR]

The article focuses on a case of a patient presenting to the emergency department with symptoms such as diffuse abdominal pain, nausea, vomiting, and increased urinary frequency, leading to a diagnosis of diabetes mellitus. Topics include the patient's clinical manifestations, laboratory data, and the subsequent management of diabetes with insulin therapy.

Introduction: Nephronophthisis (NPHP) is a tubulointerstitial kidney disorder with an autosomal recessive inheritance pattern. Its genetic heterogeneity contributes to phenotype variability. The most frequent etiology of juvenile nephronophthisis is a mutation in the nephronophthisis type 1 (NPHP1) gene. This study aimed to evaluate the genotype-phenotype correlation in NPHP1 gene mutation. Methods: A multicenter retrospective study was performed over 20 years from 1998 to 2018 to describe the clinical, biological, and radiological features associated with the large deletion NPHP1 gene in 32 patients. Results: The incidence of NPHP1 was 1.6/204041. Eighty-one percent of our patients were born out of consanguineous marriages. The mean age at diagnosis was 14 ± 7 years. The patients were divided into three groups: isolated nephronophthisis (72%), syndromic nephronophthisis (19%), and patients without recognizable syndrome (9%). Intrafamilial and geographical variability was observed in syndrome diagnoses and in age at the onset of CKD stage 5. Genotype frequency varied between 50% and 100% in genealogical data. Juvenile (47%), adolescent (37%), and adult (13%) clinical forms have been distinguished by the onset of CKD stage 5. The five-year survival rate of renal transplantation was 80%. Conclusion: Given the broad clinical spectrum of NPHP1 associated with the large deletion of the NPHP1 gene, no genotype-phenotype correlation could be established. [ABSTRACT FROM AUTHOR]

Background: Caroli's disease is characterized by non-obstructive dilatation of intrahepatic biliary radicals with formation of calculi followed by recurrent episodes of cholangitis. It is a rare congenital malformation and often remains silent, diagnosed accidentally. But if kept unattended, and without any early intervention, it may lead to fatal residual complications. Hence, its early recognition is of utmost importance to prevent recurrent cholangitis, hepatic abscess, liver cirrhosis and cholangiocarcinoma. Hence, we feel that this case must be reported so as to increase awareness among physicians regarding this entity. Case presentation: We hereby report a case of 10-year-old boy who reported with complaints of recurrent episodes of fever, breathing difficulty and multiple episodes of epigastric abdominal pain with apparently healthy siblings. His routine investigation, laboratory parameters were within normal limits. Ultrasonography abdomen showed liver with normal echo-texture with varying sized multiple thin walled cysts involving both the lobes, right more than left with saccular dilatation of 2nd and 3rd order intra-hepatic biliary radicals without calcification without any colour flow on Doppler evaluation. The common hepatic and common bile ducts were normal in calibre and lumen. Magnetic resonance imaging abdomen had similar findings and upper GI endoscopy was also normal. He was finally diagnosed to be a case of Caroli's disease and was managed with broad spectrum antibiotics, ursodeoxycholic acid, multivitamins, and calcium supplements. He made an uneventful recovery thereafter. Parents were counselled about the risk of cholangitis and cholangiocarcinoma and was referred to tertiary care centre for genetic counselling and for future need of liver transplantation. Conclusion: Age presentation of Caroli's disease varies. Majority present during adolescence and early adulthood. This often poses a diagnostic challenge owing its rare entity and silent presentation. A strong index of suspicion and prompt diagnosis is warranted to prevent its fatal residual complications. [ABSTRACT FROM AUTHOR]

Purpose: Report on the diagnosis of prenatally detected fetal kidneys with bilateral polycystic appearance in a single center between 1999 and 2020 with special focus on renal morphology and biometry, amniotic fluid and extrarenal findings and proposal for an diagnostic algorithm. Methods: Retrospective observational study including pregnancies with prenatally detected kidneys with bilateral polycystic appearance (n = 98). Cases and outcomes were compared according to prenatal findings with special focus on renal morphology, amount of amniotic fluid, and presence of extrarenal abnormalities. Results: Most frequent diagnoses were autosomal recessive polycystic kidney disease (ARPKD, 53.1%), Meckel–Gruber syndrome (MKS, 17.3%) and autosomal dominant polycystic kidney disease (ADPKD, 8.2%). Other diagnoses included: Joubert-, Jeune-, McKusick–Kaufman- and Bardet–Biedl syndrome, overgrowth syndromes, Mainzer–Saldino syndrome and renal tubular dysgenesis. Renal abnormalities most frequently observed were hyperechogenic parenchyma, kidney enlargement, changes of corticomedullary differentiation and cystic changes of various degree. Oligo- and anhydramnios were mainly seen in ARPKD, RTD and second-trimester MKS. Extrarenal findings included skeletal (35.7%) and cardiac (34.7%) abnormalities as well as abnormalities of the central nervous system (27.6%). Conclusion: Gestational age at manifestation, kidney size, visibility of cysts, echogenicity, amniotic fluid volume, and the presence of associated extrarenal malformations allow to differentiate between the most frequent underlying diseases presenting with bilateral polycystic kidneys on prenatal ultrasound by following a diagnostic algorithm. [ABSTRACT FROM AUTHOR]

A rare congenital hepatobiliary disorder called Caroli's disease is characterized by multifocal segmental dilatation of intrahepatic bile ducts that can affect the entire liver or only specific areas of it. Coexisting conditions with Caroli's disease include autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD). ADPKD results in the development of cysts, which are tiny fluid-filled sacs, in the kidneys. Caroli's disease is considered a rare disorder, affecting a small number of individuals worldwide. The symptoms of Caroli's disease can vary from person to person and it also may overlap with other liver and biliary disorders. As a result, it may be challenging to diagnose and manage the condition due to limited awareness and expertise. Increased awareness, research, and specialized medical care are crucial in improving outcomes for individuals affected by this rare disorder. This study involves the case of a 60- year-old woman presented with abdominal pain, fever, weight loss, and jaundice. Her imaging test endoscopic retrograde cholangiopancreatography (ERCP) signifies Caroli's disease with pancreatic duct (PD) calculi and management involves supportive care with antibiotics. Antibiotics were prescribed to prevent or treat infections such as cholangitis and nutritional supplement was recommended in managing Caroli's disease. The patient underwent pancreatic stent placement and was discharged with regular follow-up. So, this case highlights the clinical and diagnostic aspects to improve disease understanding and the progression of Caroli's illness along with ADPKD. [ABSTRACT FROM AUTHOR]

Autosomal-recessive polycystic kidney disease (ARPKD; MIM #263200) is a severe, hereditary, hepato-renal fibrocystic disorder that causes early childhood morbidity and mortality. Mutations in the polycystic kidney and hepatic disease 1 (PKHD1) gene, which encodes the protein fibrocystin/polyductin complex (FPC), cause all typical forms of ARPKD. Several mouse lines carrying diverse, genetically engineered disruptions in the orthologous Pkhd1 gene have been generated, but none expresses the classic ARPKD renal phenotype. In the current study, we characterized a spontaneous mouse Pkhd1 mutation that is transmitted as a recessive trait and causes cysticliver (cyli), similar to the hepato-biliary disease in ARPKD, but which is exacerbated by age, sex, and parity. We mapped the mutation to Chromosome 1 and determined that an insertion/deletion mutation causes a frameshift within Pkhd1 exon 48, which is predicted to result in a premature termination codon (UGA). Pkhd1cyli/cyli (cyli) mice exhibit a severe liver pathology but lack renal disease. Further analysis revealed that several alternatively spliced Pkhd1 mRNA, all containing exon 48, were expressed in cyli kidneys, but in lower abundance than in wild-type kidneys, suggesting that these transcripts escaped from nonsense-mediated decay (NMD). We identified an AAAAAT motif in exon 48 upstream of the cyli mutation which could enable ribosomal frameshifting, thus potentially allowing production of sufficient amounts of FPC for renoprotection. This mechanism, expressed in a species-specific fashion, may help explain the disparities in the renal phenotype observed between Pkhd1 mutant mice and patients with PKHD1-related disease. Key messages: The Pkhd1cyli/cyli mouse expresses cystic liver disease, but no kidney phenotype. Pkhd1 mRNA expression is decreased in cyli liver and kidneys compared to wild-type. Ribosomal frameshifting may be responsible for Pkhd1 mRNA escape from NMD. Pkhd1 mRNA escape from NMD could contribute to the absent kidney phenotype. [ABSTRACT FROM AUTHOR]

Metformin (MET) has the potential to activate p‐AMPK and block mTORC1‐induced proliferation of tubular cells in PKD kidneys. The aim of this study was to determine the effects of MET on cyst growth, kidney function, AMPK and mTOR signaling, and lactate levels in male PCK rats, a Pkhd1 gene mutation model of human autosomal recessive polycystic kidney disease (ARPKD). MET 300 mg/kg/day IP from days 28 to 84 of age resulted in a mean serum metformin level that was 10 times the upper limit of therapeutic, no effect on cyst indices, nephrotoxicity, and increased serum lactate. MET 150 mg/kg resulted in a therapeutic serum metformin level but had no effect on kidney weight, cyst indices, kidney function, or mTOR and autophagy proteins. In summary, a standard dose of MET was ineffective in reducing PKD, did not activate p‐AMPK or suppress mTOR and the higher dose resulted in increased lactate levels and nephrotoxicity. In conclusion, the study dampens enthusiasm for human studies of MET in PKD. Doubling the metformin dose resulted in a 10‐fold increase in mean blood levels and toxicity suggesting that the dosage range between therapeutic and toxic is narrow. [ABSTRACT FROM AUTHOR]